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  • Quantification of bovine leukemia virus proviral DNA using a low-cost real-time polymerase chain reaction
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-11
    M.I. Petersen, I. Alvarez, K.G. Trono, J.P. Jaworski

    The detection of bovine leukemia virus (BLV) proviral DNA is an important tool to address whether an animal is infected with BLV. Compared with serological assays, real-time PCR accounts for greater sensitivity and can serve as a confirmatory test for the clarification of inconclusive or discordant serological test results. However, the high cost related to real-time PCR assays has limited their systematic inclusion in BLV surveillance and eradication programs. The aim of the present study was to validate a low-cost quantitative real-time PCR. Interestingly, by using SYBR Green detection dye, we were able to reduce the cost of a single reaction by a factor of 5 compared with most common assays based on the use of fluorogenic probes (i.e., TaqMan technology). This approach allowed a highly sensitive and specific detection and quantification of BLV proviral DNA from purified peripheral blood leukocytes and a milk matrix. Due to its simplicity and low cost, our in-house BLV SYBR quantitative real-time PCR might be used either as a screening or as a confirmatory test in BLV control programs.

    更新日期:2018-04-12
  • Effects of treatment of preweaning dairy calves with recombinant bovine somatotropin on immune responses and somatotropic axis
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-11
    A.L. Belli, R.B. Reis, A. Veronese, R. Moreira, K. Flanagan, J. Driver, C.D. Nelson, J.A. Clapper, M.A. Ballou, K.C. Jeong, R.C. Chebel

    Weaning may be associated with negative energy balance and body weight loss when calves are still immunologically immature, predisposing them to infectious diseases. The aim of the present experiment was to investigate the effects of treatment of preweaning dairy calves with recombinant bovine somatotropin (rbST) on the somatotropic axis, selected immune parameters, and hematology of calves around weaning. Thirty-six Holstein female calves were randomly assigned to receive 1.5 to 1.8 mg of rbST (Posilac, Elanco Animal Health, Greenfield, IN) per kilogram of body weight or to receive injections of saline (saline solution 0.9%, Valley Vet Supply, Marysville, KS) every 7 d from 21 to 63 d of life. Calves were fed milk replacer ad libitum from birth to 38 d of age (d −11), when progressive weaning started, and calves were weaned at 49 d of age (d 0). Calves were weighed at birth and weekly from 21 to 63 d of age, when wither height also was measured. Calves were vaccinated with 0.5 mg of ovalbumin on study d −28 and −7. Blood samples were collected on d −28, −25, −21, −11, 0, 3, 7, and 14. Polymorphonuclear leukocytes were isolated and challenged ex vivo with Escherichia coli to determine phagocytosis and oxidative burst capacity. Additionally, expression of cluster of differentiation (CD)62L and CD18 by granulocyte, lymphocyte, and CD14+ monocyte were determined. Blood samples were also used to determine hematological parameters and concentrations of growth hormone, insulin-like growth factor-1, insulin, glucose, fatty acids, β-hydroxybutyrate, haptoglobin, and anti-ovalbumin IgG. Calves treated with rbST had greater concentrations of growth hormone and insulin-like growth factor-1 from d −25 to 14 than control calves, whereas insulin, fatty acid, and β-hydroxybutyrate concentrations did not differ. On d −11, glucose concentration was greater for rbST-treated calves. Treatment did not affect polymorphonuclear lymphocyte phagocytosis and oxidative burst, but intensity of expression of CD62L and CD18 by granulocytes tended to be increased by rbST treatment. Treatment did not affect the concentration of anti-ovalbumin IgG in serum. Haptoglobin concentration was reduced in rbST treated calves on d 3 and we noted a tendency for hematocrit to be lower in rbST-treated calves. Treatment did not affect body weight, wither height, and average daily gain, despite the fact that rbST-treated calves had lower daily milk replacer intake. The relatively minor improvements in immune responses resulting from rbST treatment of weaning calves may not be sufficient to reduce the incidence of infectious diseases.

    更新日期:2018-04-12
  • In vitro bioassessment of the immunomodulatory activity of Saccharomyces cerevisiae components using bovine macrophages and Mycobacterium avium ssp. paratuberculosis
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-11
    Z. Li, H. Kang, Q. You, F. Ossa, P. Mead, M. Quinton, N.A. Karrow

    The yeast Saccharomyces cerevisiae and its components are used for the prevention and treatment of enteric disease in different species; therefore, they may also be useful for preventing Johne's disease, a chronic inflammatory bowel disease of ruminants caused by Mycobacterium avium ssp. paratuberculosis (MAP). The objective of this study was to identify potential immunomodulatory S. cerevisiae components using a bovine macrophage cell line (BOMAC). The BOMAC phagocytic activity, reactive oxygen species production, and immune-related gene (IL6, IL10, IL12p40, IL13, IL23), transforming growth factor β, ARG1, CASP1, and inducible nitric oxide synthase expression were investigated when BOMAC were cocultured with cell wall components from 4 different strains (A, B, C, and D) and 2 forms of dead yeast from strain A. The BOMAC phagocytosis of mCherry-labeled MAP was concentration-dependently attenuated when BOMAC were cocultured with yeast components for 6 h. Each yeast derivative also induced a concentration-dependent increase in BOMAC reactive oxygen species production after a 6-h exposure. In addition, BOMAC mRNA expression of the immune-related genes was investigated after 6 and 24 h of exposure to yeast components. All yeast components were found to regulate the immunomodulatory genes of BOMAC; however, the response varied among components and over time. The in vitro bioassessment studies reported here suggest that dead yeast and its cell wall components may be useful for modulating macrophage function before or during MAP infection.

    更新日期:2018-04-12
  • Associations between bone and energy metabolism in cows fed diets differing in level of dietary cation-anion difference and supplemented with cholecalciferol or calcidiol
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-11
    R.M. Rodney, N.P. Martinez, P. Celi, E. Block, P.C. Thomson, G. Wijffels, D.R. Fraser, J.E.P. Santos, I.J. Lean

    Bone-derived hormones play an important role in metabolism. This study examined the hypothesis that interactions between bone and energy metabolism, particularly those involving osteocalcin, are present in dairy cattle and have feedback mechanisms over time. Associations between metabolites in blood were examined in 32 Holstein cows blocked by parity and milk yield and randomly allocated to diets containing either 0.27 mg/kg dry matter (DM) calcidiol or cholecalciferol for an anticipated intake of 3 mg/d (120,000 IU/d) at 11 kg of DM, and positive (+130 mEq/kg DM) or negative (−130 mEq/kg DM) dietary cation-anion difference (DCAD) from 252 d of gestation to calving. Blood was sampled every 3 d, from 9 d prepartum to 30 d postpartum, and plasma concentrations of vitamin D3, 25-hydroxyvitamin D3, adiponectin, C-telopeptide of type 1 collagen (CTX1), glucose, insulin-like growth factor 1 (IGF1), insulin, undercarboxylated osteocalcin (uOC), and carboxylated osteocalcin (cOC) were determined. Feeding calcidiol compared with cholecalciferol increased plasma concentrations of 25-hydroxyvitamin D3 pre- (264.2 ± 8.0 vs. 61.3 ± 8.0 ng/mL) and postpartum (170.8 ± 6.2 vs. 51.3 ± 6.2 ng/mL) but decreased concentrations of vitamin D3 pre- (1.2 ± 0.6 vs. 14.5 ± 0.6 ng/mL) and postpartum (1.9 ± 0.4 vs. 3.2 ± 0.6 ng/mL). Prepartum, cows fed the negative DCAD diet had reduced concentrations of vitamin D3 and glucose compared with cows fed a positive DCAD. The combination of negative DCAD and cholecalciferol reduced IGF1 concentrations prepartum. The DCAD treatment had no effect on postpartum concentrations of metabolites. Nulliparous cows had increased concentrations of OC, CTX1, IGF1, glucose, and insulin compared with parous cows. Time series analysis identified associations between metabolites on the same day and over 3-d lags up to ±9 d that suggest feedback between 25-hydroxyvitamin D3 and vitamin D3 in the negative lags, indicating that 25-hydroxyvitamin D3 may exert feedback on vitamin D3 but not vice versa. We found evidence of a feedback mechanism between vitamin D3 and IGF1, with positive effect size (ES) on the same day and 3 d later, and negative ES 9 d later, that was more evident in cholecalciferol-fed cows. This suggests an important role of IGF1 in integrating bone metabolism with energy and protein metabolic pathways. Evidence of feedback was found between uOC and particularly cOC with IGF1, with positive ES on the same day but negative ES 6 d before and 6 d after. An association between uOC or cOC and IGF1 has not been previously identified in cattle and suggests that both uOC and cOC may have marked biological activity. Associations between OC and insulin identified in mice were not observed herein, although associations between OC and glucose were similar to those between IGF1 and glucose, supporting associations between glucose, OC, and IGF1. We provide further statistical evidence of crosstalk between vitamin D compounds, bone hormones, and energy metabolism in cattle. In particular, associations between uOC or cOC and IGF1 may provide links between prepartum diets and observations of prolonged increases in milk production and allow better control of peripartum metabolism.

    更新日期:2018-04-12
  • Effects of feeding milk replacer at 2 rates with pelleted, low-starch or texturized, high-starch starters on calf performance and digestion
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-11
    J.D. Quigley, T.M. Hill, T.S. Dennis, F.X. Suarez-Mena, R.L. Schlotterbeck

    Milk replacer (MR) feeding programs have traditionally fed at less than ad libitum amounts to promote calf starter (CS) intake and allow early weaning. More recently, increased amounts of MR preweaning have been shown to increase preweaning ADG, although postweaning growth may be reduced. Several studies suggest that limited postweaning digestion of nutrients in CS may contribute to postweaning growth impairment. It is not clear whether CS formulation might also contribute to differences in postweaning nutrient digestion when calves are fed different MR programs. A 56-d feeding and digestion trial was conducted to compare growth and digestion in 2- to 3-d-old male Holstein calves (n = 48; initially 41.9 kg of body weight) fed a moderate (MRM) or high (MRH) MR program and either a pelleted CS containing 9.9% starch or a texturized CS containing 41.3% starch. Programs were 0.66 kg of dry matter (DM)/d of MR to d 46, then 0.33 kg/d to d 49 (MRM) and 0.85 kg of DM/d to d 5, then 1.07 kg/d to d 42, then 0.53 kg/d to d 49 (MRH). The MR contained 25% crude protein and 18.6% fat and was reconstituted to 13 (MRM) or 15% (MRH) solids. Calves were also assigned randomly to receive a pelleted CS (9.9% starch, 36.9% NDF) or a textured CS (41.3% starch, 13.3% NDF) and water for ad libitum intake for 56 d. During d 31 to 35 and 52 to 56, fecal samples were collected from 5 calves per treatment for estimates of digestibility. Selected nutrients and chromic oxide (d 31–35) or acid-insoluble ash (d 52–56) were analyzed in feed and feces to estimate digestibility. Data were analyzed as a completely randomized design. Repeated measures analysis was performed when data were measured by week. Calves fed MRH gained more body weight (but not hip width) and were more efficient to weaning compared with calves fed MRM, although fecal scores and days treated with medications were greater. We found no effect of CS on animal performance, although calves fed textured CS had higher fecal scores. Digestibilities of nutrients were affected by treatment and time of sampling (5 or 8 wk). At 5 wk, digestion of DM, organic matter, crude protein, and fat were lower and digestion of acid detergent fiber, neutral detergent fiber, and starch were higher in calves fed MRM and reflected greater CS intake. Also, digestion of DM, organic matter, acid detergent fiber, starch, crude protein, and fat were greater in calves fed textured CS at 5 wk. By 8 wk, when CS was the only source of nutrients, digestion of DM, organic matter, acid detergent fiber, and neutral detergent fiber were greater in calves fed MRM and digestion of DM and organic matter were greater, and acid detergent fiber and neutral detergent fiber digestion were lower in calves fed textured CS. Formulation of CS as well as amount of MR offered to young calves influenced animal performance and digestion in this study.

    更新日期:2018-04-12
  • Interaction between the physical forms of starter and forage source on growth performance and blood metabolites of Holstein dairy calves
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-11
    H. Omidi-Mirzaei, A. Azarfar, A. Kiani, M. Mirzaei, M.H. Ghaffari

    The objective of this study was to investigate the effects of the physical forms of starter and forage sources on feed intake, growth performance, rumen pH, and blood metabolites of dairy calves. Forty male Holstein calves (41.3 ± 3.5 kg of body weight) were used (n = 10 calves per treatment) in a 2 × 2 factorial arrangement of treatments with the factors being physical forms of starter (coarse mash and texturized) and forage source [alfalfa hay (AH) and wheat straw (WS)]. Individually housed calves were randomly assigned to 1 of the 4 dietary treatments, including (1) coarsely mashed (CM; coarse ground grains combined with a mash supplement) starter feed with AH (CM-AH), (2) coarsely mashed starter feed with WS (CM-WS), (3) texturized feed starter (TF; includes steam-flaked corn, steam-rolled barley combined with a pelleted supplement) with AH (TF-AH), and (4) TF with WS (TF-WS). Both starters had the same ingredients and nutrient compositions but differed in their physical forms. Calves were weaned on d 56 and remained in the study until d 70. All calves had free access to drinking water and the starter feeding at all times. No interaction was detected between the physical forms of starter feeds and forage source concerning starter intake, dry matter intake, metabolizable energy (ME) intake, average daily gain (ADG)/ME intake, ADG, and feed efficiency (FE). The preweaning and overall starter feed intake, dry matter intake, and ME intake were greater for calves fed TF starter diets than those fed CM starter diets. The ADG/ME intake was greater for calves fed TF starter diets than that fed CM starter. The FE was greater for calves fed TF starter diets compared with those fed CM starter during the preweaning, postweaning, and overall periods. The WS improved FE during the postweaning period compared with AH. The physical form of starter, forage source, and their interaction did not affect plasma glucose, triglycerides, and very low-density lipoprotein concentrations. Ruminal pH was greater for calves fed TF starter diets than those fed CM starter on d 30 of life. An interaction was observed between the physical forms of starter diets and forage source for β-hydroxybutyrate on d 28. These results showed that when starter diets contained similar ingredients and nutrient contents, processing calf starters to reduce the number of fine particles can improve the growth performance in dairy calves. Furthermore, the provision of WS improved FE and ADG of calves during the postweaning period.

    更新日期:2018-04-12
  • Laboratory evaluation of a novel rapid tube test system for differentiation of mastitis-causing pathogen groups
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-11
    S. Leimbach, V. Krömker

    Because clinical mastitis, one of the most common diseases in dairy cows, is routinely treated with antimicrobial substances, it offers a high potential for future reduction of antimicrobial usage. In fact, intramammary antibiotic administration is not advisable in cases of clinical mastitis caused by coliform bacteria, yeasts, or protothecae or in cases with no detectable mastitis pathogen. To avoid unnecessary treatments with antimicrobials for the benefit of animal health and public welfare, the rapid identification of the mastitis-causing pathogens becomes necessary. Therefore, 4 different incubation time schemes for a newly developed tube test system (MastDecide, Quidee GmbH, Homberg, Germany) were analyzed in terms of sensitivity, specificity, negative and positive predictive values, and apparent and true prevalence compared with the conventional microbiological investigation results for 251 clinical mastitis milk samples from 11 dairy farms located in northern Germany. An aliquot (100 µL) of a quarter foremilk sample was taken in both cases. The evaluation of the tube test result after 14 h of incubation at 37°C resulted in sensitivity values of 83.6, 72.2, and 70.7% and specificity values of 94.1, 83.3, and 90.8% for gram-positive cocci, coliform bacteria, and no growth or further pathogens, respectively. Moreover, for the present pathogen distribution, the overall tube test sensitivity was highest after 14 h of incubation (sensitivity = 80.9%; specificity = 70.7%). The described tube test system has the potential to provide a new option for an evidence-based mastitis therapy, with the aim of reducing the future usage of antimicrobials in dairy cows and a larger goal of decreasing antimicrobial resistance. However, a subsequent on-farm test validation should be performed before implementation in an evidence-based mastitis therapy concept can be recommended.

    更新日期:2018-04-12
  • Selected reaction monitoring mass spectrometry of mastitis milk reveals pathogen-specific regulation of bovine host response proteins
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-11
    Ulrike Kusebauch, Lorenzo E. Hernández-Castellano, Stine L. Bislev, Robert L. Moritz, Christine M. Røntved, Emøke Bendixen

    Mastitis is a major challenge to bovine health. The detection of sensitive markers for mastitis in dairy herds is of great demand. Suitable biomarkers should be measurable in milk and should report pathogen-specific changes at an early stage to support earlier diagnosis and more efficient treatment. However, the identification of sensitive biomarkers in milk has remained a challenge, in part due to their relatively low concentration in milk. In the present study, we used a selected reaction monitoring (SRM) mass spectrometry approach, which allowed the absolute quantitation of 13 host response proteins in milk for the first time. These proteins were measured over a 54-h period upon an in vivo challenge with cell wall components from either gram-negative (lipopolysaccharide from Escherichia coli; LPS) or gram-positive bacteria (peptidoglycan from Staphylococcus aureus; PGN). Whereas our data clearly demonstrate that all challenged animals have consistent upregulation of innate immune response proteins after both LPS and PGN challenge, the data also reveal clearly that LPS challenge unleashes faster and shows a more intense host response compared with PGN challenge. Biomarker candidates that may distinguish between gram-negative and gram-positive bacteria include α-2 macroglobulin, α-1 antitrypsin, haptoglobin, serum amyloid A3, cluster of differentiation 14, calgranulin B, cathepsin C, vanin-1, galectin 1, galectin 3, and IL-8. Our approach can support further studies of large cohorts of animals with natural occurring mastitis, to validate the relevance of these suggested biomarkers in dairy production.

    更新日期:2018-04-12
  • An evaluation of the effectiveness of a chemical additive based on sodium benzoate, potassium sorbate, and sodium nitrite on the fermentation and aerobic stability of corn silage
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-11
    Limin Kung Jr., Megan L. Smith, Erica Benjamim da Silva, Michelle C. Windle, Thiago C. da Silva, Stephanie A. Polukis

    We evaluated the effectiveness of an additive comprising sodium benzoate, potassium sorbate, and sodium nitrite (SSL) as active ingredients for its ability to improve the aerobic stability of corn silages made in North America. In experiment 1, treatment with SSL (1.5 and 2.0 L/t) on whole-plant corn (WPC) was compared with treatment with an additive containing buffered propionic acid and citric acid (BPA; 2 L/t) on corn harvested at 32 and 38% DM and ensiled for 120 d. Silage treated with BPA was higher in ammonia-N and propionic acid relative to other treatments. Treatments with all of the additives had numerically, but not statistically, fewer yeasts compared with untreated silage. Both application rates of SSL resulted in lower concentrations of ethanol compared with untreated and BPA silages. Treatment with BPA improved the aerobic stability of silages compared with untreated silage, but the effect from SSL was markedly greater. In experiment 2, WPC was untreated or treated with 2 or 3 L of SSL/t or a microbial inoculant containing Enterococcus faecium M74, Lactobacillus plantarum CH6072, and Lactobacillus buchneri LN1819 (final total lactic acid bacteria application rate of 150,000 cfu/g of fresh forage). Silages were air stressed for 24 h at 28 and 42 d of storage and ensiled for 49 d before opening. Inoculation had no effect on acid end products, ethanol, number of yeasts, or aerobic stability compared with other treatments. Treatment with SSL decreased the amount of ethanol, had no effect on number of yeasts, and improved aerobic stability in a dose-dependent manner compared with other treatments. In experiment 3, WPC was untreated or treated with 2 L of SSL/t and ensiled for 5, 15, and 30 d. Treatment with SSL resulted in silage with fewer yeasts and lower concentrations of ethanol after all times of ensiling compared with untreated silage. In addition, SSL improved aerobic stability after each period of ensiling, but the effect was more at 15 and 30 d compared with 5 d of storage. Treating WPC with SSL can improve the aerobic stability of corn silage made in North America, and the effect can be observed as soon as 5 d after ensiling.

    更新日期:2018-04-12
  • Feeding reduced-fat dried distillers grains with solubles to lactating Holstein dairy cows does not alter milk composition or cause late blowing in cheese
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-11
    E.D. Testroet, D.C. Beitz, M.R. O'Neil, A.L. Mueller, H.A. Ramirez-Ramirez, S. Clark

    Feeding dried distillers grains with solubles (DDGS) to lactating dairy cows has been implicated as a cause of late blowing defects in the production of Swiss-style cheeses. Our objectives were (1) to test the effect of feeding reduced-fat DDGS (RF-DDGS; ∼6% fat) to lactating dairy cows on the composition of milk and on the suitability of the milk for production of baby Swiss cheese and (2) to evaluate the effect of diet on cow lactation performance. Lactating Holstein dairy cows were fed both dietary treatments in a 2 × 2 crossover design. Cows were housed in a 48-cow freestall pen equipped with individual feeding gates to record feed intake. The control diet was a corn, corn silage, and alfalfa hay diet supplemented with mechanically expelled soybean meal. The experimental diet was the same base ration, but 20% (dry matter basis) RF-DDGS were included in place of the expelled soybean meal. The RF-DDGS diet was additionally supplemented with rumen-protected lysine; diets were formulated to be isoenergetic and isonitrogenous. Cows were allowed ad libitum access to feed and water, fed twice daily, and milked 3 times daily. For cheese production, milk was collected and pooled 6 times for each dietary treatment. There was no treatment effect on milk yield (35.66 and 35.39 kg/d), milk fat production (1.27 and 1.25 kg/d), milk fat percentage (3.65 and 3.61%), milk protein production (1.05 and 1.08 kg/d), lactose percentage (4.62 and 4.64%), milk total solids (12.19 and 12.28%), and somatic cell count (232.57 and 287.22 × 103 cells/mL) for control and RF-DDGS, respectively. However, dry matter intake was increased by treatment, which implied a reduction in feed efficiency. Milk protein percentage also increased (3.01 and 3.11%), whereas milk urea nitrogen decreased (14.18 and 12.99 mg/dL), indicating that protein utilization may be more efficient when cows are fed RF-DDGS. No differences in cheese were observed by a trained panel except cheese appearance; control cheese eyes were significantly, but not practically, larger than the RF-DDGS cheese. These results indicate that RF-DDGS can be effectively used in the rations of lactating Holstein cows with no deleterious effects on milk production and composition and metrics of the physiology of the cow (i.e., blood glucose and nonesterified fatty acids); however, feeding RF-DDGS increased dry matter intake, which decreased feed efficiency. Finally, feeding RF-DDGS did not negatively influence quality and suitability of milk for production of baby Swiss cheese.

    更新日期:2018-04-12
  • Influence of adipocyte size and adipose depot on the number of adipose tissue macrophages and the expression of adipokines in dairy cows at the end of pregnancy
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    E. Depreester, J. De Koster, M. Van Poucke, M. Hostens, W. Van den Broeck, L. Peelman, G.A. Contreras, G. Opsomer

    The aim of this study was to determine the number of adipose tissue macrophages (ATM) and the mRNA expression of adipokines [adiponectin (ADIPOQ), leptin (LEP), interleukin 6 (IL6), tumor necrosis factor (TNF), and interleukin 10 (IL10)] in different adipose depots from cows with a variable body condition score (BCS) at the end of the dry period. We hypothesized that the number of ATM and the expression of these adipokines depend on adipocyte size and the anatomical location of the adipose depot. Subcutaneous, omental, mesenteric, perirenal, and intrapelvic adipose tissue samples were taken immediately after euthanasia of 10 Holstein Friesian dairy cows (upcoming parity 2 to 5, age 3.9 ± 1.4 yr; mean ± standard deviation) at the end of pregnancy (actual days of pregnancy at the moment of euthanasia: 269 ± 5 d). During the dry period, all animals received similar diets to meet but not exceed requirements. Five animals were considered to have a normal BCS (2.5–3.5) and 5 animals were considered to be over-conditioned (BCS = 3.75–5). Body weight of the animals at the moment of euthanasia was 717 ± 77 kg. Expression of the different genes was determined by reverse transcription quantitative real-time PCR. Adipocyte size was determined by measuring the area of 100 adipocytes on histological sections. Average adipocyte area was 10,475 ± 1,019, 8,500 ± 780, 10,383 ± 1,227, 11,466 ± 1,039, and 11,087 ± 1,632 µm2 for the subcutaneous, mesenteric, omental, intrapelvic, and perirenal adipose depot, respectively. Immunohistochemistry using anti-bovine CD172a antibodies was performed to determine the proportion of ATM (the number of CD172a-positive cells per 100 adipocytes, given as a percentage). Expression of LEP, IL6, and TNF was positively associated with adipocyte size, whereas no association could be detected between ADIPOQ and IL10 with the size of the adipocytes. The omental adipose depot was especially infiltrated with ATM (1.92 ± 0.55, 1.10 ± 0.33, and 8.28 ± 2.24% for the subcutaneous, mesenteric, and omental adipose depot, respectively). The proportion of ATM was positively associated with the size of the adipocytes in the omental and mesenteric adipose depot. Expression of ADIPOQ, LEP, IL6, TNF, and IL10 differed among depots, which suggests differences in inflammatory characteristics depending on the anatomical location of depots. In conclusion, the results of the present study confirm the adipose tissue as a potential source of inflammatory mediators and demonstrate ATM infiltration, especially in the omental adipose depot.

    更新日期:2018-04-06
  • A selective medium for the enumeration and differentiation of Lactobacillus delbrueckii ssp. bulgaricus
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    Nwadiuto O. Nwamaioha, Salam A. Ibrahim

    Modified reinforced clostridial medium (mRCM) was developed and evaluated for the differential enumeration of Lactobacillus delbrueckii ssp. bulgaricus. Lactobacillus bulgaricus, an important species of lactic acid bacteria with health benefits, is used in the production of yogurt and other fermented foods. Our results showed that supplementing reinforced clostridial medium with 0.025% CaCl2, 0.01% uracil, and 0.2% Tween 80 (mRCM) significantly enhanced the growth rate of L. bulgaricus RR and ATCC 11842 strains as measured by the optical densities of these strains after 12 h of incubation at 42°C. The bacterial populations (plate count) of the RR and ATCC 11842 strains were 0.76 and 0.77 log cfu/g higher in mRCM than in de Man, Rogosa, and Sharpe and reinforced clostridial medium media, respectively. Conversely, the population counts for other bacterial species (Bifidobacterium, Lactobacillus rhamnosus, and Lactobacillus reuteri) were significantly inhibited in the mRCM medium. The addition of aniline blue dye to mRCM (mRCM-blue) improved the selectivity of L. bulgaricus in mixed lactic bacterial cultures compared with de Man, Rogosa, and Sharpe medium and lactic agar with regard to colony appearance and morphology. The mRCM-blue performed better than the conventional medium in culturing, enumerating, and differentiating L. bulgaricus. Therefore, mRCM-blue could be used as a selective medium to enhance the growth and differentiation of L. bulgaricus in order to meet the increasing demand for this beneficial species of bacteria.

    更新日期:2018-04-06
  • Continuous 11-week feeding of reduced-fat distillers grains with and without monensin reduces lactation performance of dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    D.L. Morris, S.H. Kim, P.J. Kononoff, C. Lee

    This study investigated the effects of continuous feeding of high inclusion of reduced-fat corn distillers grains with solubles with and without monensin on dry matter intake (DMI), production, milk fatty acid profile, and plasma AA profile in lactating cows. The experiment was conducted for 12 wk (1-wk covariate, 2-wk diet adaptation, and 9-wk experimental period of data collection) with 36 Holstein cows in a randomized complete block design. Cows were blocked by parity, days in milk, and milk yield and assigned to the following diets: (1) control (CON), (2) CON with reduced-fat corn distillers grains with solubles included at 28.8% (dry matter basis) replacing soybean meal, soyhulls, and supplemental fat (DG), and (3) DG with monensin (Rumensin; Elanco Animal Health, Greenfield, IN) supplemented at a rate of 20 mg/kg of DM offered (DGMon). Orthogonal contrasts were used to compare CON versus DG and DGMon and to compare DG versus DGMon. Milk yield was not affected (40.3 vs. 40.8 kg/d) by DG and DGMon compared with CON. However, for DG and DGMon compared with CON, decreased DMI (24.9 vs. 26.4 kg/d), milk fat yield (1.12 vs. 1.55 kg/d), milk protein yield (1.24 vs. 1.32 kg/d), and energy-corrected milk yield (37.7 vs. 43.5 kg/d) were observed. Feeding DGMon compared with DG did not affect DMI (24.4 vs. 25.4 kg/d) and milk yield (39.2 vs. 41.3 kg/d) but decreased milk fat yield (1.08 vs. 1.23 kg/d), milk protein yield (1.20 vs. 1.28 kg/d), and energy-corrected milk yield (36.0 vs. 39.4 kg/d). Interactions between treatment and week for DMI, milk fat yield, and energy-corrected milk indicate that production responses to DG and DGMon versus CON were decreased over the experimental period. Cows fed DG and DGMon had increased milk fat concentration of trans-10,cis-12 18:2, trans-10 18:1, and long-chain (>16C) and polyunsaturated fatty acids and decreased short-chain (<16C) and odd- and branched-chain fatty acids compared with CON. No difference was observed between DG and DGMon in milk fatty acid profile. In the current study, feeding a high-DG diet did not sustain DMI and production, and supplementing monensin to a high-DG diet further decreased DMI and production.

    更新日期:2018-04-06
  • Robustness and sensitivity of a blueprint for on-farm estimation of dairy cow energy balance
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    Vivi M. Thorup, Mizeck G.G. Chagunda, Amelie Fischer, Martin R. Weisbjerg, Nicolas C. Friggens

    Excessive negative energy balance (EB) has been associated with decreased reproductive performance and increased risk of lameness and metabolic diseases. On-farm, automated EB estimates for individual cows would enable dairy farmers to detect excessive negative EB early and act to minimize its extent and duration by altering feeding. Previously, we have shown that EB can be estimated from frequent measurements of body weight (BW) and body condition score (BCS) changes, referred to as EBbody. In this study, we investigated the robustness and sensitivity of the EBbody method to assess its genericity and on-farm applicability. We used 5 data sets with BW of lactating cows (name of data set in parenthesis): 65 Holstein cows in a French feeding trial (INRA); 6 Holstein cows in a British feeding trial (Friggens); 31 Holstein cows and 17 Jersey cows in a Danish feeding trial (DCRC); 140 Holstein cows in a British feeding trial (Scotland's Rural College, SRUC); and 1,592 Holstein cows on 9 Danish farms with milking robots (automatic milking system). We used the INRA and Friggens data sets to develop a dynamic formula to correct BW for increasing residual gut-fill (RGF) during early lactation. With the DCRC data, we tested the effect of smoothing parameters and weighing frequency on EBbody. Also, 2 robustness tests were performed using the SRUC data to test the effect of diet change on BW and the automatic milking system data to test the effect of farm on BW variation. Finally, we combined the results into a blueprint describing different ways to calculate EBbody depending on the purpose and on the availability of BCS. The dynamic RGF adjustment resulted in a lower empty BW during early lactation than that obtained with the previously used constant RGF. The double-exponential smoothing method used to correct for meal-related gut-fill was robust to choice of smoothing parameters. Cows should be weighed at least once every 4 d during early lactation to capture the duration of negative EBbody. Our EBbody method proved robust to diet changes. Finally, although cow BW varied significantly between farms, the quantile regression smoothing of BW did not bias the estimation of weight differences between herds. In conclusion, these results validate the applicability of the EBbody method to estimate EB across a range of farm conditions, and we provided a blueprint that enables the estimation of EBbody for individual cows on-farm using only frequent BW, in combination with BCS when available.

    更新日期:2018-04-06
  • Short communication: Temporal changes in the skin morphology of dairy cows during the periparturient period
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    Banri Suzuki, Toshie Sugiyama, Chikako Yoshida, Toshihiko Nakao

    Management of dairy cow productivity requires monitoring of their nutritional status by visual observation. It has been suggested that changes in hair coat appearance are among the indicators of nutritional state in dairy cows. Temporal changes in the skin morphology in cows, however, have not been reported. In this study, we examined the changes in the skin of dairy cows that occur during the peripartum period. Seven pluriparous cows were used. Skin samples were collected at 28 d before the due date and 28 d and 56 d after calving for morphological examination. Hair follicle width was 108.8 ± 5.9 µm (±SD) in the dry period, 95.5 ± 5.5 µm at 28 d after calving, and 104.2 ± 5.3 µm at 56 d postpartum. The percentages of anagen hair follicles during these 3 periods were 41.4 ± 3.4, 18.5 ± 3.4, and 32.3 ± 3.3%, respectively. The corresponding sebaceous gland sizes were 8,362.0 ± 707.6, 7,800.0 ± 831.4, and 9,186.8 ± 962.6 µm2, respectively. Hair follicle width was positively correlated with percentage of anagen hair follicles. The thickness of epidermal and proliferation rate of epidermal cell were also correlated. However, the hair follicle width, sebaceous gland size and cell proliferation rate, and thickness and proliferation rate of epidermal cells did not show any marked changes.

    更新日期:2018-04-06
  • Exopolysaccharide from Lactobacillus plantarum LRCC5310 offers protection against rotavirus-induced diarrhea and regulates inflammatory response
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    Kiyoung Kim, Gyeonghweon Lee, Hien Dang Thanh, Jong-Hwa Kim, Maytiya Konkit, Seokmin Yoon, Miri Park, Siyoung Yang, Eunsup Park, Wonyong Kim

    We aimed to determine the effects of Lactobacillus strains against rotaviral infections. Rotaviruses are the major causative agent of acute gastroenteritis in infants and children worldwide. However, to date, no specific antiviral drugs for the treatment of rotavirus infection have been developed. We identified 263 Lactobacillus strains from 35 samples of the traditional Korean fermented vegetable food, kimchi. Among them, Lactobacillus plantarum LRCC5310, more specifically the exopolysaccharides produced by these cells, were shown to have an antiviral effect against human rotavirus Wa strain in vitro. In vivo, the oral administration of exopolysaccharides for 2 d before and 5 d after mouse infection with the murine rotavirus epidemic diarrhea of infant mice strain led to a decrease in the duration of diarrhea and viral shedding and prevented the destruction of enteric epithelium integrity in the infected mice. We demonstrated here that the exopolysaccharides extracted from L. plantarum LRCC5310 can be used for the effective control of rotavirus infection.

    更新日期:2018-04-06
  • Yeast culture increased plasma niacin concentration, evaporative heat loss, and feed efficiency of dairy cows in a hot environment
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    Julia D.L. Dias, Rayana B. Silva, Tatiane Fernandes, Eugenio F. Barbosa, Larissa E.C. Graças, Rafael C. Araujo, Renata A.N. Pereira, Marcos N. Pereira

    The supplementation of dairy cows with yeast culture may increase diet digestibility, plasma niacin concentration, heat dissipation, and lactation performance. Our objective was to evaluate the response of Holstein cows in late lactation (234 ± 131 d in milk) to dead yeast culture (YC, 15 g/d, Factor SC, GRASP, Saccharomyces cerevisiae) during Brazilian summer (temperature-humidity index >68 for 92.2% of the time). Thirty-two cows were individually fed a standard total mixed ration for 14 d and control (CTL) or YC treatments for 35 d, in a covariate adjusted complete randomized block design. Response was evaluated in wk 5 or as repeated measures over time. Cows were milked 3 times per day and treatments (YC or placebo) were orally dosed to each cow before each milking. Plasma niacin was 1.50 for CTL and 1.66 µg/mL for YC. The YC reduced rectal temperature, respiration rate, and skin temperature, whereas it tended to increase sweating rate. The proportion of cows with rectal temperature ≥39.2°C on CTL and YC was, respectively, 8 and 0% at 0730 h, 52 and 25% at 1500 h, and 35 and 26% at 2200 h. Plasma glucose was increased by YC. The total-tract apparent digestibility of nutrients, plasma urea N concentration, molar proportion of ruminal VFA, and urinary allantoin excretion were not affected by YC. Cows fed YC were less selective against feed particles >19 mm in the morning, in the afternoon were more selective against long feed particles and in favor of particles <8 mm, and refused short particles at night. Milk yield was not different (30.5 kg/d for CTL and 30.2 kg/d for YC). Feeding YC reduced dry matter intake (20.3 vs. 19.4 kg/d) and the digestible organic matter intake (15.6 vs. 13.9 kg/d). The inclusion of YC increased the ratios of milk to dry matter intake (1.50 vs. 1.64) and energy-corrected milk to dry matter intake (1.81 vs. 1.98). The covariate adjusted body weight (648 kg) and body condition score (3.0) did not differ. Milk solids yields and concentrations, linear somatic cell count, and milk urea N were also similar. The supplementation of YC increased plasma niacin concentration, body heat loss, and feed efficiency of late lactation dairy cows by reducing intake at similar milk yield.

    更新日期:2018-04-06
  • Jugular arginine infusion relieves lipopolysaccharide-triggered inflammatory stress and improves immunity status of lactating dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    F.F. Zhao, T.Y. Wu, H.R. Wang, L.Y. Ding, Gulzar Ahmed, H.W. Li, W. Tian, Y.Z. Shen

    The objective of this study was to evaluate the effects of jugular l-Arg infusion on performance and immune function during lipopolysaccharide (LPS)-induced inflammation of lactating dairy cows. Eight Holstein cows (multiparous, 608.8 ± 31.5 kg) at mid-lactation were randomly assigned to 5-d jugular infusions of control (saline), Arg (3 g/h), LPS (0.033 μg/kg per h), and LPS + Arg (0.033 μg/kg per h of LPS and 3 g/h of Arg) in a replicated 4 × 4 Latin square design with 4 infusion periods separated by 10-d noninfusion periods. Jugular solutions of saline, Arg, LPS, and LPS + Arg were continuously infused using peristaltic pumps for approximately 6 h/d during infusion periods. Milk yield was measured on each day of the infusion period. Milk samples were obtained on the last 2 d of each infusion period, and blood samples were obtained on the last day of each infusion period before infusion (0 h) and at 3 and 6 h. We found that the jugular LPS infusion significantly increased serum concentrations of IL-1β, IL-6, tumor necrosis factor, inducible nitric oxide synthase, and lipopolysaccharide binding protein, whereas Arg attenuated the increase in IL-6 and inducible nitric oxide synthase levels and tended to decrease the lipopolysaccharide binding protein level. Arginine alleviated the decrease in dry matter intake and milk fat yield and the increase of somatic cell count induced by LPS. Total casein in milk was decreased during the LPS-induced inflammation period, and jugular Arg infusion significantly increased the content of total casein. In contrast, lactalbumin in milk increased during the LPS-induced inflammation period, whereas jugular Arg infusion significantly decreased the content of lactalbumin. The concentrations of plasma Gly, Thr, Ile, Leu, Arg, Phe, and total free AA were significantly decreased by LPS treatment, but Arg attenuated this tendency. These results indicated that jugular Arg infusion (18 g/d) has protective effects on relieving inflammatory stress and improving immunity status triggered by LPS. In conclusion, Arg could attenuate inflammatory stress and improve milk performance of lactating dairy cows. This protective effect may be due to the ability of Arg to suppress LPS effects and improve immunity status.

    更新日期:2018-04-06
  • An observational cohort study on persistency of internal teat sealant residues in milk after calving in dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    Fidèle Kabera, Simon Dufour, Greg Keefe, Jean-Philippe Roy

    Our objectives were to evaluate the prevalence of quarters with an observable internal teat sealant (ITS) plug at first milking following calving and investigate persistency of ITS residues in milk after calving. An observational cohort study was carried out on 557 quarters of 156 cows treated with ITS in 6 farms in Quebec, Canada. The presence of an ITS plug at first milking and ITS residues in milk at each milking were observed by producers. The effects of various factors on the odds of observing an ITS plug and persistency of ITS residues in milk were studied using generalized logistic mixed and generalized negative binomial mixed models, respectively. Milk samples were taken on the day before dry-off and on 2 occasions after calving for bacterial identification to detect intramammary infection (IMI) using bacteriological culture followed by MALDI-TOF identification. The association between the absence of an ITS plug and the presence of new IMI was assessed using a mixed logistic regression model. Internal teat sealant plugs after calving were more often observed in rear quarters and in quarters receiving ITS alone at drying-off versus antimicrobial and ITS. We observed an average (standard deviation) persistency of 4.0 d (2.3 d). When an ITS plug was still present at first milking (83% of quarters), the elimination of ITS residues in milk after calving was significantly longer (4.5 d, on average) compared with 1.2 d when an ITS plug was absent. In cows with an ITS plug at calving, we observed a higher number of days of excretion in older cows. When a plug could not be observed, rear quarters, older cows, and cows with a long dry period duration excreted ITS residues for a significantly longer period. The lack of a significant association between the absence of a plug and the odds of new IMI at calving suggests that despite the loss of the plug, cows were still protected against new IMI. Although we were able to highlight some statistically significant risk factors explaining persistency of ITS residues following calving, observed differences were often relatively small and, perhaps, not clinically relevant. In conclusion, an ITS plug was present until first milking after calving for 83% quarters, quarters without an ITS plug at first milking appeared to have been protected from new IMI, and ITS residues could be observed in milk up to 12 d in milk.

    更新日期:2018-04-06
  • A canonical discriminant analysis to study the association between milk fatty acids of ruminal origin and milk fat depression in dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    G. Conte, C. Dimauro, A. Serra, N.P.P. Macciotta, M. Mele

    Although milk fat depression (MFD) has been observed and described since the beginning of the last century, all the molecular and biochemical mechanisms involved are still not completely understood. Some fatty acids (FA) originating during rumen biohydrogenation have been proposed as causative elements of MFD. However, contradictory results were obtained when studying the effect of single FA on MFD. An alternative could be the simultaneous evaluation of the effect of many FA using a multivariate approach. The aim of this study was to evaluate the relationship between individual milk FA of ruminal origin and MFD using canonical discriminant analysis, a multivariate technique able to distinguish 2 or more groups on the basis of a pool of variables. In a commercial dairy herd, a diet containing 26% starch on a DM basis induced an unintentional MFD syndrome in 14 cows out of 40. Milk yielded by these 14 animals showed a fat content lower than 50% of the ordinary value, whereas milk production and protein content were normal. The remaining 26 cows secreted typical milk fat content and therefore were considered the control group, even though they ate the same diet. The stepwise discriminant analysis selected 14 milk FA of ruminal origin most able to distinguish the 2 groups. This restricted pool of FA was used, as variables, in a run of the canonical discriminant analysis that was able to significantly discriminate between the 2 groups. Out of the 14 FA, 5 conjugated linoleic acid isomers (C18:2 trans-10,trans-12, C18:2 trans-8,trans-10, C18:2 trans-11,cis-13, C18:2 cis-9,cis-11, C18:2 cis-10,cis-12) and C15:0 iso were more related to the control group, whereas C18:2 trans-10,cis-12, C16:1 trans-6–7, C16:1 trans-9, C18:1 trans-6–8, C18:1 trans-9, C18:1 trans-10, C18:1 cis-11, and C18:3n-3 were positively associated with the MFD group, allowing a complete discrimination. On the basis of these results, we can conclude that (1) the shift of ruminal biohydrogenation from C18:1 trans-11 to C18:1 trans-10 seemed to be strongly associated with MFD; (2) at the same time, other C18:1 trans isomers showed a similar association; (3) on the contrary, conjugated linoleic acid isomers other than C18:2 trans-10,cis-12 seemed to be associated with a normal fat secretion. Results confirmed that MFD is the consequence of a combined effect of the outflow of many ruminal FA, which collectively affect mammary fat synthesis. Because the animals of the 2 groups were fed the same diet, these results suggested that factors other than diet are involved in the MFD syndrome. Feeding behavior (i.e., ability to select dietary ingredients in a total mixed ration), rumen environment and the composition of ruminal bacteria are additional factors able to modify the products of rumen biohydrogenation. Results of the present work confirmed that the multivariate approach can be a useful tool to evaluate a metabolic pathway that involves several parameters, providing interesting suggestions about the role of some FA involved in MFD. However, results about the MFD syndrome obtained in the present research require a deep molecular investigation to be confirmed.

    更新日期:2018-04-06
  • On-farm deaths of dairy cows are associated with features of freestall barns
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    K. Sarjokari, M. Hovinen, L. Seppä-Lassila, M. Norring, T. Hurme, O.A.T. Peltoniemi, T. Soveri, P.J. Rajala-Schultz

    On-farm death (OFD) of a dairy cow is always a financial loss for a farmer, and potentially a welfare issue that has to be addressed within the dairy industry. The aim of this study was to explore the associations between OFD of dairy cows, housing, and herd management in freestall barns. To achieve the goal, we followed 10,837 cows calving in 2011 in 82 herds. Data were gathered with observations and a structured interview during farm visits and from a national dairy herd improvement database. The hazard of OFD was modeled with a shared frailty survival model, with SAS 9.3 PHREG procedure (SAS Institute Inc., Cary, NC). The study population was 58% Ayrshire and 42% Holstein cows. The median herd size and mean milk yield in the study herds were 116 cows and 9,151 kg of milk per cow per year. The overall probability of OFD was 6.0%; 1.8% of the cows died unassisted and 4.2% were euthanized. Variation in OFD percentage between individual herds was large, from 0 to 16%, accounting for 0 to 58% of all removals in the herds. Keeping close-up dry cows in an own group was associated with higher hazard of OFD [hazard ratio (HR) = 1.37] compared with keeping them in the same pen with far-off dry cows. Higher hazard on OFD was observed when barns had only one kind of calving pens; single (HR = 2.09) or group pens (HR = 1.72), compared with having both of those types. The hazard of OFD was lower if the whole herd was housed in barns or pens that had only 1 type of feed barrier at the feed bunk, namely post-and-rail (HR = 0.51) or a type with barriers between the cow's heads (HR = 0.49), compared with having 2 types. Lower OFD hazard was observed with wider than 340 cm of walking alley next to the feeding table (HR = 0.75), and with housing a whole herd in pens with only 1 type of walking alley surface, specifically slatted (HR = 0.53) or solid (HR = 0.48), compared with having both types. The hazard of OFD was higher with stalls wider than 120 cm (HR = 1.38) compared with narrower stalls. The hazard of OFD was also associated with breed, parity, and calving season. This study identified many factors that contribute to the incidence of OFD of dairy cows. The solutions for reducing on-farm mortality include housing, management, and breeding choices that are most probably herd specific.

    更新日期:2018-04-06
  • Invited review: Current perspectives on eating and rumination activity in dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    K.A. Beauchemin

    Many early studies laid the foundation for our understanding of the mechanics of chewing, the physiological role of chewing for the cow, and how chewing behavior is affected by dietary characteristics. However, the dairy cow has changed significantly over the past decades, as have the types of diets fed and the production systems used. The plethora of literature published in recent years provides new insights on eating and ruminating activity of dairy cows. Lactating dairy cows spend about 4.5 h/d eating (range: 2.4–8.5 h/d) and 7 h/d ruminating (range: 2.5–10.5 h/d), with a maximum total chewing time of 16 h/d. Chewing time is affected by many factors, most importantly whether access to feed is restricted, intake of neutral detergent fiber from forages, and mean particle size of the diet. Feed restriction and long particles (≥19 mm) have a greater effect on eating time, whereas intake of forage neutral detergent fiber and medium particles (4–19 mm) affects rumination time. It is well entrenched in the literature that promoting chewing increases salivary secretion of dairy cows, which helps reduce the risk of acidosis. However, the net effect of a change in chewing time on rumen buffing is likely rather small; therefore, acidosis prevention strategies need to be broad. Damage to plant tissues during mastication creates sites that provide access to fungi, adhesion of bacteria, and formation of biofilms that progressively degrade carbohydrates. Rumination and eating are the main ways in which feed is reduced in particle size. Contractions of the rumen increase during eating and ruminating activity and help move small particles to the escapable pool and into the omasum. Use of recently developed low-cost sensors that monitor chewing activity of dairy cows in commercial facilities can provide information that is helpful in management decisions, especially when combined with other criteria. Although accuracy and precision can be somewhat variable depending on sensor and conditions of use, relative changes in cow behavior, such as a marked decrease in rumination time of a cow or sustained low rumination time compared with a contemporary group of cows, can be used to help detect estrus, parturition, and some illnesses. This review provides a comprehensive understanding of the dietary, animal, and management factors that affect eating and ruminating behavior in dairy cows and presents an overview of the physiological importance of chewing with emphasis on recent developments and practical implications for feeding and managing the modern housed dairy cow.

    更新日期:2018-04-06
  • Performance of human observers and an automatic 3-dimensional computer-vision-based locomotion scoring method to detect lameness and hoof lesions in dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    Andrés Schlageter-Tello, Tom Van Hertem, Eddie A.M. Bokkers, Stefano Viazzi, Claudia Bahr, Kees Lokhorst

    The objective of this study was to determine if a 3-dimensional computer vision automatic locomotion scoring (3D-ALS) method was able to outperform human observers for classifying cows as lame or nonlame and for detecting cows affected and nonaffected by specific type(s) of hoof lesion. Data collection was carried out in 2 experimental sessions (5 mo apart). In every session all cows were assessed for (1) locomotion by 2 observers (Obs1 and Obs2) and by a 3D-ALS; and (2) identification of different types of hoof lesions during hoof trimming (i.e., skin and horn lesions and combinations of skin/horn lesions and skin/hyperplasia). Performances of observers and 3D-ALS for classifying cows as lame or nonlame and for detecting cows affected or nonaffected by types of lesion were estimated using the percentage of agreement (PA), kappa coefficient (κ), sensitivity (SEN), and specificity (SPE). Observers and 3D-ALS showed similar SENlame values for classifying lame cows as lame (SENlame comparison Obs1-Obs2 = 74.2%; comparison observers-3D-ALS = 73.9–71.8%). Specificity values for classifying nonlame cows as nonlame were lower for 3D-ALS when compared with observers (SPEnonlame comparison Obs1-Obs2 = 88.5%; comparison observers-3D-ALS = 65.3–67.8%). Accordingly, overall performance of 3D-ALS for classifying cows as lame and nonlame was lower than observers (Obs1-Obs2 comparison PAlame/nonlame = 84.2% and κlame/nonlame = 0.63; observers-3D-ALS comparisons PAlame/nonlame = 67.7–69.2% and κlame/nonlame = 0.33–0.36). Similarly, observers and 3D-ALS had comparable and moderate SENlesion values for detecting horn (SENlesion Obs1 = 68.6%; Obs2 = 71.4%; 3D-ALS = 75.0%) and combinations of skin/horn lesions (SENlesion Obs1 = 51.1%; Obs2 = 64.5%; 3D-ALS = 53.3%). The SPEnonlesion values for detecting cows without lesions when classified as nonlame were lower for 3D-ALS than for observers (SPEnonlesion Obs1 = 83.9%; Obs2 = 80.2%; 3D-ALS = 60.2%). This was translated into a poor overall performance of 3D-ALS for detecting cows affected and nonaffected by horn lesions (PAlesion/nonlesion Obs1 = 80.6%; Obs2 = 78.3%; 3D-ALS = 63.5% and κlesion/nonlesion Obs1 = 0.48; Obs2 = 0.44; 3D-ALS = 0.25) and skin/horn lesions (PAlesion/nonlesion Obs1 = 75.1%; Obs2 = 75.9%; 3D-ALS = 58.6% and κlesion/nonlesion Obs1 = 0.35; Obs2 = 0.42; 3D-ALS = 0.10), when compared with observers. Performance of observers and 3D-ALS for detecting skin lesions was poor (SENlesion for Obs1, Obs2, and 3D-ALS <40%). Comparable SENlame and SENlesion values for observers and 3D-ALS are explained by an overestimation of lameness by 3D-ALS when compared with observers. Thus, comparable SENlame and SENlesion were reached at the expense high number of false positives and low SPEnonlame and SPEnonlesion. Considering that observers and 3D-ALS showed similar performance for classifying cows as lame and for detecting horn and combinations of skin/horn lesions, the 3D-ALS could be a useful tool for supporting dairy farmers in their hoof health management.

    更新日期:2018-04-06
  • Effects of rumen-undegradable protein on intake, performance, and mammary gland development in prepubertal and pubertal dairy heifers
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    A.L. Silva, E. Detmann, J. Dijkstra, A.M. Pedroso, L.H.P. Silva, A.F. Machado, F.C. Sousa, G.B. dos Santos, M.I. Marcondes

    The objective of this study was to evaluate the influence of different amounts of rumen-undegradable protein (RUP) on intake, N balance, performance, mammary gland development, carcass traits, and hormonal status of Holstein heifers at different physiological stages (PS). Sixteen prepubertal (PRE) heifers (initial BW = 106 ± 7.6 kg; age = 4.3 ± 0.46 mo) and 16 pubertal (PUB) heifers (initial BW = 224 ± 7.9 kg; age = 12.6 ± 0.45 mo) were used in an experiment over a period of 84 d. Four diets with increasing RUP contents (38, 44, 51, and 57% of dietary crude protein) and heifers at 2 PS (PRE or PUB) were used in a 4 × 2 factorial arrangement of treatments in a completely randomized design. Throughout the experiment, 2 digestibility trials were performed over 5 consecutive days (starting at d 36 and 78) involving feed and ort sampling and spot collections of feces and urine. At d 0 and 83, body ultrasound images were obtained for real-time carcass trait evaluation. The mammary gland was ultrasonically scanned at d 0 and every 3 wk during the experiment. Blood samples were taken at d 0 and 84 to determine serum concentrations of progesterone, estrogen, insulin-like growth factor I (IGF-I), and insulin. No interaction between PS and the level of RUP was found for any trait. Apparent digestibility of dry matter, organic matter, and neutral detergent fiber corrected for ash and protein was not affected by RUP level but was lower for PRE compared with PUB heifers. Sorting against neutral detergent fiber corrected for ash and protein (tendency only) and for crude protein was greater for PUB than PRE heifers. Pubertal heifers had greater average daily gain (905 vs. 505 g/d) and N retention (25.9 vs. 12.5 g/d) than PRE heifers. In addition, average daily gain and N retention were greatest at 51% RUP of dietary protein. Mammary ultrasonography indicated no effects of RUP amounts on mammary gland composition, whereas PRE heifers had greater pixel values than PUB, indicating higher contents of fat rather than protein in the mammary glands of PRE heifers. Serum progesterone and IGF-I concentration was affected only by PS, and PRE heifers had greater values of progesterone and IGF-I concentrations than PUB heifers. Serum insulin concentration was unaffected by PS but tended to be higher at 51% of RUP. In conclusion, an RUP level of 51% increases body weight, average daily gain, feed efficiency, and N retention in heifers regardless of the PS. In addition, PRE heifers have a lower sorting ability and reduced intake, total-tract digestibility, and N retention. They also have higher amounts of fat in their mammary glands, even at moderate growth rates.

    更新日期:2018-04-06
  • Effect of milk centrifugation and incorporation of high-heat-treated centrifugate on the composition, texture, and ripening characteristics of Maasdam cheese
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    Prabin Lamichhane, Alan L. Kelly, Jeremiah J. Sheehan

    This study investigated the effect of centrifugation (9,000 × g, 50°C, flow rate = 1,000 L/h), as well as the incorporation of high-heat-treated (HHT) centrifugate into cheese milk on the composition, texture, and ripening characteristics of Maasdam cheese. Neither centrifugation nor incorporation of HHT centrifugate into cheese milk had a pronounced effect on the compositional parameters of any experimental cheeses, except for moisture and moisture in nonfat substance (MNFS) levels. Incorporation of HHT centrifugate at a rate of 6 to 10% of the total milk weight into centrifuged milk increased the level of denatured whey protein in the cheese milk and also increased the level of MNFS in the resultant cheese compared with cheeses made from centrifuged milk and control cheeses; moreover, cheese made from centrifuged milk had ∼3% higher moisture content on average than control cheeses. Centrifugation of cheese milk reduced the somatic cell count by ∼95% relative to the somatic cell count in raw milk. Neither centrifugation nor incorporation of HHT centrifugate into cheese milk had a significant effect on age-related changes in pH, lactate content, and levels of primary and secondary proteolysis. However, the value for hardness was significantly lower for cheeses made from milk containing HHT centrifugate than for other experimental cheese types. Overall, centrifugation appeared to have little effect on composition, texture, and ripening characteristics of Maasdam cheese. However, care should be taken when incorporating HHT centrifugate into cheese milk, because such practices can influence the level of moisture, MNFS, and texture (particularly hardness) of resultant cheeses. Such differences may have the potential to influence subsequent eye development characteristic, although no definitive trends were observed in the present study and further research on this is recommended.

    更新日期:2018-04-06
  • Technical note: A simple rumen collection device for calves: An adaptation of a manual rumen drenching system
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    R.N. Klopp, M.J. Oconitrillo, A. Sackett, T.M. Hill, R.L. Schlotterbeck, G.J. Lascano

    A limited amount of research is available related to the rumen microbiota of calves, yet there has been a recent spike of interest in determining the diversity and development of calf rumen microbial populations. To study the microbial populations of a calf's rumen, a sample of the rumen fluid is needed. One way to take a rumen fluid sample from a calf is by fistulating the animal. This method requires surgery and can be very stressful on a young animal that is trying to adapt to a new environment and has a depressed immune system. Another method that can be used instead of fistulation surgery is a rumen pump. This method requires a tube to be inserted into the rumen through the calf's esophagus. Once inside the rumen, fluid can be pumped out and collected in a few minutes. This method is quick, inexpensive, and does not cause significant stress on the animal. This technical note presents the materials and methodology used to convert a drenching system into a rumen pump and its respective utilization in 2 experiments using dairy bull calves.

    更新日期:2018-04-06
  • Use of on-farm emergency slaughter for dairy cows in British Columbia
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-04-05
    Katherine E. Koralesky, David Fraser

    On-farm emergency slaughter (OFES), whereby inspection, stunning, and bleeding occur on the farm before the carcass is transported to a slaughterhouse, is permitted in some jurisdictions as a means to avoid inhumane transportation while salvaging meat from injured animals. However, OFES is controversial and its use for dairy cows has been little studied. Inspection documents for 812 dairy cows were examined to identify how OFES was used for dairy cows in British Columbia, Canada, over 16.5 mo. Producers used OFES for dairy cows aged 1 to 13 yr (median of 4 yr). Leg, hip, nerve, spinal, foot, and hind-end injuries or conditions (in that order) were the most common reasons for OFES, and some cases may have been a consequence of calving. Foot conditions were disproportionately common among cows 5 yr and older, and hind-end conditions were disproportionately common among cows 6 yr and older. Producers used OFES promptly after traumatic injury (within 1 d) for some cows, but OFES was delayed for others, sometimes until cows had been nonambulatory for 2 to 6 d. In some cases, OFES was used for nontraumatic chronic conditions, such as lameness and hind-end weakness, rather than traumatic injuries such as fractures and dislocated hips. Use of OFES appears to conform to the purpose of the program when used promptly after traumatic injuries, but clear guidelines are needed to avoid inappropriate use and delays that may prolong animal suffering.

    更新日期:2018-04-06
  • Effects of spray-dried plasma protein product on early-lactation dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    C. Lee, A.W. Tebbe, J.M. Campbell, W.P. Weiss

    Spray-dried plasma protein (SDP) compared with blood meal (BM) may contain various functional and active components that may benefit animal health. The objective of this experiment was to investigate the effects of feeding SDP or BM on production and blood profile in dairy cows during the transition and early-lactation periods. Seventy-two Holstein cows at 14 d before calving were used in a randomized block design. During the prepartum period, cows were fed a typical late-gestation diet containing BM (100 g/cow per day; 100BM, n = 24) or SDP (100 g/cow per day; 100SDP; n = 48). After calving, cows that were fed BM prepartum were fed a typical lactation diet formulated to provide 100 g/d of BM (100BM). Half the cows that were fed 100SDP prepartum were fed a lactation diet formulated to provide 100 g/d of SDP (100SDP; n = 24), and half were fed a diet formulated to provide 400 g/d of SDP (400SDP; n = 24) on a dry matter basis where SDP replaced BM (100SDP) or BM and soybean products (400SDP). All diets were balanced for crude protein concentration and metabolizable protein supply assuming BM and SDP were equal in rumen-degradable protein and rumen-undegradable protein. All data were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC) as a randomized block design where contrasts were made for 100BM versus 100SDP for prepartum variables and 100BM versus 100SDP and 100SDP versus 400SDP for postpartum variables. Prepartum supplementation of SDP had no effect on plasma fatty acids and β-hydroxybutyrate (2 d before calving). Plasma fatty acids (255 ± 29 µEq/mL) and β-hydroxybutyrate (675 ± 70 µmol/L) at 8 and 14 d of lactation were not affected by SDP in the diet. Feeding SDP at 100 g/d compared with 100BM increased or tended to increase milk fat, protein, and lactose contents for 16 wk after parturition. Providing SDP at 400 g/d in the diet increased milk yield (42 vs. 39 kg/d), energy-corrected milk (44 vs. 41 kg/d), energy-corrected milk per kilogram of dry matter intake, and yields of milk fat (1.60 vs. 1.48 kg/d), protein (1.21 vs. 1.16 kg/d), and lactose compared with 100SDP. Body weight losses tended to be lower for 100SDP compared with 100BM without a difference between 100SDP and 400SDP. Plasma histidine concentration (d 14 of lactation) was lower for SDP compared with 100BM. In addition, plasma 1-methyl-l-histidine tended to be lower as inclusion rate of SDP increased. In conclusion, SDP at 400 g/d increased milk and milk component yields without an increase in feed intake. Studies evaluating effects of functional and active compounds in SDP on gut microbiome, gut health, and immune functions may be needed to determine mode of action.

    更新日期:2018-03-29
  • Interaction of 5-hydroxy-l-tryptophan and negative dietary cation-anion difference on calcium homeostasis in multiparous peripartum dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    C.J. Slater, E.L. Endres, S.R. Weaver, A.A. Cheng, M.R. Lauber, S.F. Endres, E. Olstad, A. DeBruin, P.M. Crump, E. Block, L.L. Hernandez

    Hypocalcemia affects almost 50% of all dairy cows. Our laboratory has previously demonstrated that infusions of the serotonin precursor 5-hydroxy-l-tryptophan (5-HTP) increase circulating calcium concentrations in the Holstein transition cow. It is unknown whether feeding a negative DCAD diet alters the relationship between 5-HTP and hypocalcemia. The main objective of this study was to determine whether feeding a negative dietary cation-anion difference (−DCAD) diet before calving in conjunction with 5-HTP treatment could further diminish the magnitude of hypocalcemia at the time of calving. We used a randomized complete block design with a 2 × 2 factorial arrangement. Thirty-one multiparous Holstein cows were fed either a positive (+13 mEq/100 g) or negative (−13 mEq/100 g) DCAD diet 21 d before parturition and were intravenously infused daily with saline or 5-HTP (1 mg/kg) starting 7 d before the estimated date of parturition. Cows were blocked by parity and were randomly assigned to 1 of 4 treatment groups: positive DCAD plus saline, positive DCAD plus 5-HTP, negative DCAD plus saline, and negative DCAD plus 5-HTP, resulting in n = 8 per group. Total calcium (tCa), ionized calcium (iCa), and feed intake were recorded. The iCa was elevated prepartum in the −DCAD/5-HTP group compared with the other treatment groups as well as on d 0 and 1 postpartum. Although differences in tCa were not significant across the pre- or postpartum periods, tCa was numerically higher on d 0 and significantly higher on d 1 in −DCAD/5-HTP cows compared with all other groups. Prepartum the −DCAD/5-HTP treatment group ate less than the other treatment groups; however, postpartum dry matter intake differences were not significant. These findings demonstrate that feeding a −DCAD diet in conjunction with 5-HTP prepartum can increase postpartum circulating iCa concentrations and therefore diminish the magnitude of hypocalcemia at the time of parturition.

    更新日期:2018-03-29
  • Use of a culture-independent on-farm algorithm to guide the use of selective dry-cow antibiotic therapy
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    A.K. Vasquez, D.V. Nydam, C. Foditsch, M. Wieland, R. Lynch, S. Eicker, P.D. Virkler

    An algorithm using only computer-based records to guide selective dry-cow therapy was evaluated at a New York State dairy farm via a randomized field trial. DairyComp 305 (Valley Ag Software, Tulare, CA) and Dairy Herd Improvement Association test-day data were used to identify cows as low risk (cows that might not benefit from dry-cow antibiotics) or high risk (cows that will likely benefit). Low-risk cows were those that had all of the following: somatic cell count (SCC) ≤200,000 cells/mL at last test, an average SCC ≤200,000 cells/mL over the last 3 tests, no signs of clinical mastitis at dry-off, and no more than 1 clinical mastitis event in the current lactation. Low-risk cows were randomly assigned to receive intramammary antibiotics and external teat sealant (ABXTS) or external teat sealant only (TS) at dry-off. Using pre-dry-off and postcalving quarter-level culture results, low-risk quarters were assessed for microbiological cure risk and new infection risk. Groups were also assessed for differences in first-test milk yield and linear scores, individual milk weights for the first 30 d, and culling and mastitis events before 30 d in milk. A total of 304 cows and 1,040 quarters in the ABXTS group and 307 cows and 1,058 quarters in the TS group were enrolled. Among cows to be dried, the proportion of cows that met low-risk criteria was 64% (n = 611/953). Of cultures eligible for bacteriological cure analysis (n = 171), 93% of ABXTS cured, whereas 88% of TS cured. Of the non-cures, 95% were contributed by the minor pathogens coagulase-negative staphylococci (n = 19/20). These organisms also accounted for 57.5% of new infections (n = 77/134). We found no statistical differences between treatment groups for new infection risk (TS = 7.3% quarters experiencing new infections; ABXTS = 5.5%), milk production (ABXTS = 40.5 kg; TS = 41.2 kg), linear scores (ABXTS = 2.5; TS = 2.7), culling events (ABXTS, n = 18; TS, n = 15), or clinical mastitis events (ABXTS, n = 9; TS, n = 5). Results suggest that the algorithm used decreased dry-cow antibiotic use by approximately 60% without adversely affecting production or health outcomes.

    更新日期:2018-03-29
  • Quantitative polymerase chain reaction coupled with sodium dodecyl sulfate and propidium monoazide for detection of viable Staphylococcus aureus in milk
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    Lei Dong, Huimin Liu, Lu Meng, Mengru Xing, Jiaqi Wang, Cheng Wang, He Chen, Nan Zheng

    Conventional quantitative PCR (qPCR) are unable to differentiate DNA of viable Staphylococcus aureus cells from dead ones. The aim of this study was to use sodium dodecyl sulfate (SDS) and propidium monoazide (PMA) coupled with lysostaphin to detect viable Staph. aureus. The cell suspensions were treated with SDS and PMA before DNA extraction. The SDS is an anionic surfactant, which can increase the permeability of dead cells to PMA without compromising the viability of live cells. The lysostaphin was applied to improve the effectiveness of DNA extraction. The reliability and specificity of this method were further determined by the detection of Staph. aureus in spiked milk. The results showed that there were significant differences between the SDS-PMA-qPCR and qPCR when a final concentration of 200 μg/mL of lysostaphin was added in DNA extraction. The viable Staph. aureus could be effectively detected when SDS and PMA concentrations were 100 µg/mL and 40 μM, respectively. Compared with conventional qPCR, the SDS-PMA-qPCR assay coupled with lysostaphin was more specific and sensitive. Therefore, this method could accurately detect the number of viable Staph. aureus cells.

    更新日期:2018-03-29
  • Essential oil and monensin affect ruminal fermentation and the protozoal population in continuous culture
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    D. Ye, S.K.R. Karnati, B. Wagner, J.L. Firkins, M.L. Eastridge, J.M. Aldrich

    The interaction of monensin and essential oil was hypothesized to suppress protozoa and methane production while maintaining normal rumen function. The objective of this study was to determine the effects of feeding monensin (MON) and CinnaGar (CIN, a commercial blend of cinnamaldehyde and garlic oil) on ruminal fermentation characteristics. Continuous culture fermentors (n = 4) were maintained in 4 experimental periods in a 4 × 4 Latin square design. Four dietary treatments were arranged in a 2 × 2 factorial: (1) control diet, 37 g/d of dry matter (40 g/d at ∼92.5% dry matter) of a 50:50 forage:concentrate diet containing no additive; (2) MON at 11 g/909 kg of dry matter; (3) CIN at 0.0043% of dry matter; and (4) a combination of MON and CIN at the levels in (2) and (3). Treatment had no effects on protozoal populations, concentration of NH3N, total N flow of effluent, production of total volatile fatty acids, or flows of conjugated linoleic acid and total C18 fatty acids. The MON decreased acetate:propionate ratio and biohydrogenation of both total C18 and 18:1 cis-9 but increased protozoal generation time, concentration of peptide, and flow of 18:1 trans-11. The MON tended to decrease protozoal counts in effluent and flow of 18:0 but tended to increase propionate production. The CIN decreased true organic matter digestibility and protozoal N flow of effluent but increased nonammonia, nonmicrobial N flow. The CIN tended to decrease protozoal counts, microbial N flow, and neutral detergent fiber digestibility but tended to increase biohydrogenation of total C18, 18:2, and 18:3. The CIN tended to increase isovalerate production. The MON and CIN tended to interact for increased methane production and bacterial N flow. A second experiment was conducted to determine the effects of MON and CIN on protozoal nitrogen and cell volume in vitro. Four treatments included (1) control (feed only), (2) feed + 0.0043% dry matter CIN, (3) feed + 2.82 μM MON, and (4) feed + CIN + MON at the same levels as in (2) and (3). With no interactions, MON addition decreased percentage of protozoa that were motile and tended to decrease cell volume at 6 h. The CIN did not affect cell count or other indicators of motility or volume at either 3 or 6 h. Under the conditions of our study, we did not detect an additive response for MON and CIN to decrease protozoal counts or methane production. A 3-dimensional method is suggested to better estimate protozoal cell volume.

    更新日期:2018-03-29
  • Responses of dairy cows with divergent residual feed intake as calves to metabolic challenges during midlactation and the nonlactating period
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    K. DiGiacomo, E. Norris, F.R. Dunshea, B.J. Hayes, L.C. Marett, W.J. Wales, B.J. Leury

    Residual feed intake (RFI) is defined as the difference between the actual and expected feed intake required to support animal maintenance and growth. Thus, a cow with a low RFI can obtain nutrients for maintenance and growth from a reduced amount of feed compared with a cow with a high RFI. Variation in RFI is underpinned by a combination of factors, including genetics, metabolism, thermoregulation and body composition; hypothalamic-pituitary-adrenal (HPA) axis responsiveness is also a possible contributor. Responses to 3 metabolic challenges were measured in lactating and nonlactating dairy cattle. Sixteen Holstein Friesian cows with phenotypic RFI measurements that were obtained during the growth period (188–220 d old) were grouped as either low-calfhood RFI (n = 8) or high-calfhood RFI (n = 8). An ACTH (2 µg/kg of body weight), insulin (0.12 U/kg), and epinephrine (a low dose of 0.1 µg/kg and a high dose of 1.6 µg/kg of epinephrine) challenge were each conducted during both midlactation (122 ± 23.4 d in milk) and the nonlactating period (dry period; approximately 38 d after cessation of milking). Cows were housed in metabolism stalls for the challenges and were fed a diet of alfalfa cubes ad libitum for at least 10 d before the experiment (lactating cows also were offered a total of 6 kg of dry matter/d of crushed wheat grain plus minerals fed as 3 kg of dry matter at each milking) and were fasted for 12 h before the challenges. The efficiency of conversion of feed into milk (the ratio of feed consumed to milk produced over the 7 d before the experiment) during midlactation was better (lower) in low-calfhood RFI cows, although dry matter intake did not differ between RFI groups. Low-calfhood RFI cows exhibited a lower plasma cortisol response to the ACTH challenge than high-calfhood RFI cows, particularly in midlactation (−15%). The low-calfhood RFI cows had a greater plasma insulin-like growth factor-1 response to the insulin challenge and plasma fatty acid response to epinephrine compared with the high-calfhood RFI cows. These data suggest that high-calfhood RFI cows exhibit a more responsive HPA axis. As divergence in RFI measured during growth is retained (although reduced) during lactation, it is possible that energy is used to respond to HPA axis activation at the expense of production in high-calfhood RFI dairy cattle during lactation and contributes to a decrease in overall feed use efficiency.

    更新日期:2018-03-29
  • Effect of human chorionic gonadotrophin administration 2 days after insemination on progesterone concentration and pregnancy per artificial insemination in lactating dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    J.M. Sánchez, F. Randi, C. Passaro, D.J. Mathew, S.T. Butler, P. Lonergan

    The aim of this study was to examine the effect of a single administration of human chorionic gonadotrophin (hCG) during the establishment of the corpus luteum (CL) on progesterone (P4) concentration and pregnancy per artificial insemination (P/AI) in lactating dairy cows. Postpartum spring-calving lactating dairy cows (n = 800; mean ± SD days in milk and parity were 78.5 ± 16.7 and 2.3 ± 0.8, respectively) on 3 farms were enrolled on the study. All cows underwent the same fixed-time AI (FTAI) protocol involving a 7-d progesterone-releasing intravaginal device with gonadotrophin-releasing hormone (GnRH) administration at device insertion, prostaglandin at device removal followed by GnRH 56 h later, and AI 16 h after the second GnRH injection. Cows were blocked on days postpartum, body condition score, and parity and randomly assigned to receive either 3,000 IU of hCG 2 d after FTAI or no further treatment (control). Blood samples were collected on d 7 and 14 postestrus by coccygeal venipuncture on a subset of 204 cows to measure serum P4 concentration, and pregnancy was diagnosed by ultrasonography approximately 30 and 70 d after FTAI. Administration of hCG caused an increase in circulating P4 concentrations compared with the control treatment on d 7 (+22.2%) and d 14 (+25.7%). The P/AI at 30 d after FTAI was affected by treatment, farm, body condition score, and calving to service interval. Overall, administration of hCG decreased P/AI (46.3% vs. 55.1% for the control). Among cows that did not become pregnant following AI, a greater proportion of control cows exhibited a short repeat interval (≤17 d) compared with cows treated with hCG (8.6% vs. 2.8%, respectively). In addition, the percentages of cows pregnant at d 21 (59.6% vs. 52.0%) and d 42 (78.3% vs. 71.9%) were greater in control than in hCG-treated cows. The overall incidence of embryo loss was 10.7% and was not affected by treatment. There was a tendency for an interaction between treatment and CL status at synchronization protocol initiation for both P4 concentration and P/AI. In conclusion, administration of hCG 2 d after FTAI increased circulating P4 concentrations. Unexpectedly, cows treated with hCG had lower fertility; however, this negative effect on fertility was manifested primarily in cows lacking a CL at the onset of the synchronization protocol.

    更新日期:2018-03-29
  • Technical note: High-throughput method for antifungal activity screening in a cheese-mimicking model
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    Lucille Garnier, Marcia Leyva Salas, Nicolas Pinon, Norman Wiernasz, Audrey Pawtowski, Emmanuel Coton, Jérôme Mounier, Florence Valence

    In this study, we developed a high-throughput antifungal activity screening method using a cheese-mimicking matrix distributed in 24-well plates. This method allowed rapid screening of a large variety of antifungal agent candidates: bacterial fermented ingredients, bacterial isolates, and preservatives. Using the proposed method, we characterized the antifungal activity of 44 lactic acid bacteria (LAB) fermented milk-based ingredients and 23 LAB isolates used as protective cultures against 4 fungal targets (Mucor racemosus, Penicillium commune, Galactomyces geotrichum, and Yarrowia lipolytica). We also used this method to determine the minimum inhibitory concentration of a preservative, natamycin, against 9 fungal targets. The results underlined the strain-dependency of LAB antifungal activity, the strong effect of fermentation substrate on this activity, and the effect of the screening medium on natamycin minimum inhibitory concentration. Our method could achieved a screening rate of 1,600 assays per week and can be implemented to evaluate antifungal activity of microorganisms, fermentation products, or purified compounds compatible with dairy technology.

    更新日期:2018-03-29
  • Short communication: Pair housing dairy calves in modified calf hutches
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    L. Whalin, D.M. Weary, M.A.G. von Keyserlingk

    The objective of this study was to test if body weight (BW) and starter intake increased and reaction to novelty decreased for preweaning Holstein heifer calves pair housed in modified hutches (n = 8 pairs) versus individually housed in a single hutch (n = 14 calves). Calves were alternately assigned to housing treatment at d 5 of age. Cross sucking was recorded in 5-min scans for 30 min after milk feeding once per week over 14 wk. Calf health and BW were measured weekly from birth until approximately 88 d. When calves were 60 d old they underwent a food neophobia test where they were exposed to a novel feed for the first time. Cross sucking was observed only 5 times (in 4 different pairs) over the entire milk-feeding period. Pair-housed calves ate more starter than individually housed calves [0.89 (0.72–1.08) vs. 0.48 (0.42–0.56) kg/d; median and confidence interval], these calves also consumed 2.6 times more novel feed in the neophobia test (150 ± 27 vs. 58 ± 20 g/30 min). We observed no effect of treatment on BW. We concluded that social housing in modified hutches promotes solid feed intake and decreases fearfulness in dairy calves.

    更新日期:2018-03-29
  • Prediction accuracy of direct and indirect approaches, and their relationships with prediction ability of calibration models
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    T.K. Belay, B.S. Dagnachew, S.A. Boison, T. Ådnøy

    Milk infrared spectra are routinely used for phenotyping traits of interest through links developed between the traits and spectra. Predicted individual traits are then used in genetic analyses for estimated breeding value (EBV) or for phenotypic predictions using a single-trait mixed model; this approach is referred to as indirect prediction (IP). An alternative approach [direct prediction (DP)] is a direct genetic analysis of (a reduced dimension of) the spectra using a multitrait model to predict multivariate EBV of the spectral components and, ultimately, also to predict the univariate EBV or phenotype for the traits of interest. We simulated 3 traits under different genetic (low: 0.10 to high: 0.90) and residual (zero to high: ±0.90) correlation scenarios between the 3 traits and assumed the first trait is a linear combination of the other 2 traits. The aim was to compare the IP and DP approaches for predictions of EBV and phenotypes under the different correlation scenarios. We also evaluated relationships between performances of the 2 approaches and the accuracy of calibration equations. Moreover, the effect of using different regression coefficients estimated from simulated phenotypes (βp), true breeding values (βg), and residuals (βr) on performance of the 2 approaches were evaluated. The simulated data contained 2,100 parents (100 sires and 2,000 cows) and 8,000 offspring (4 offspring per cow). Of the 8,000 observations, 2,000 were randomly selected and used to develop links between the first and the other 2 traits using partial least square (PLS) regression analysis. The different PLS regression coefficients, such as βp, βg, and βr, were used in subsequent predictions following the IP and DP approaches. We used BLUP analyses for the remaining 6,000 observations using the true (co)variance components that had been used for the simulation. Accuracy of prediction (of EBV and phenotype) was calculated as a correlation between predicted and true values from the simulations. The results showed that accuracies of EBV prediction were higher in the DP than in the IP approach. The reverse was true for accuracy of phenotypic prediction when using βp but not when using βg and βr, where accuracy of phenotypic prediction in the DP was slightly higher than in the IP approach. Within the DP approach, accuracies of EBV when using βg were higher than when using βp only at the low genetic correlation scenario. However, we found no differences in EBV prediction accuracy between the βp and βg in the IP approach. Accuracy of the calibration models increased with an increase in genetic and residual correlations between the traits. Performance of both approaches increased with an increase in accuracy of the calibration models. In conclusion, the DP approach is a good strategy for EBV prediction but not for phenotypic prediction, where the classical PLS regression-based equations or the IP approach provided better results.

    更新日期:2018-03-29
  • Effects of fat supplementation to diets high in nonforage fiber on production responses of midlactation dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    C.M. Ylioja, C. Abney-Schulte, R. Stock, B.J. Bradford

    The effects of dietary nonforage fiber sources on production responses of lactating dairy cattle have been well described, but interactions with other components of the diet have been less thoroughly explored. We investigated the effects of adding 2 commonly fed fat sources to a ration featuring high levels of nonforage fiber supplied by a corn milling by-product. Midlactation Holstein cows were blocked by parity, stratified by days in milk, and randomly assigned to 1 of 6 pens (12 cows/pen). Pens were randomly assigned to treatment sequences in a 3 × 3 Latin square design, where the treatments consisted of prilled saturated fat (SAT; Energy Booster 100, Milk Specialties Co., Dundee, IL), calcium salts of long-chain fatty acids (UNS; Megalac, Church and Dwight Co. Inc., Princeton, NJ), or no added dietary fat (control), with fat sources included to provide 1.2% added fat (dry matter basis). Treatment periods were 21 d; milk and feed samples were collected and milk yield and feed intake were recorded for the last 4 d of each period. Results were analyzed with mixed models with pen as the experimental unit, and orthogonal contrasts were employed to evaluate the overall effect of added fat and the effect of fat source. Dry matter intake and milk yield tended to increase with added fat. Protein content decreased with fat supplementation, to a greater degree for UNS than for SAT, but protein yield was not affected. Fat content, fat yield, and energy-corrected milk yield were not affected by treatment. Conversion of feed to milk tended to increase for UNS compared with SAT. Fat supplementation to diets high in nonforage fiber had effects that were similar to those reported for more traditional lactation diets, except for the dry matter intake response.

    更新日期:2018-03-29
  • Intravenous lipid infusion affects dry matter intake, methane yield, and rumen bacteria structure in late-lactating Holstein cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    Ole Lamp, Henry Reyer, Winfried Otten, Gerd Nürnberg, Michael Derno, Klaus Wimmers, Cornelia C. Metges, Björn Kuhla

    Increasing the dietary fat content of ruminant diets decreases methane (CH4) production. This effect is caused by the toxic properties of fatty acids on rumen microbial populations, coating of feed particles diminishing the accessibility for microbes, and a reduction in dry matter intake (DMI). The latter effect is caused by postabsorptive long-chain fatty acids eliciting anorexic signaling; however, whether circulating long-chain fatty acids affect rumen CH4 production alike is unknown. To approach this question, 5 rumen-cannulated Holstein cows in late lactation received 2 jugular catheters and were kept in respiration chambers to measure CH4 production and DMI for 48 h. In a crossover design, cows were intravenously infused with a 20% lipid emulsion (LIPO) or 0.9% NaCl (CON). The LIPO cows received 2.1 kg of triglycerides/d [0.152 ± 0.007 g of triglycerides/(kg of BW × h)−1] consisting of 12.1% palmitic acid, 4.2% stearic acid, 31.1% oleic acid, and 52.7% linoleic acid. Blood and rumen fluid samples were taken hourly during the day. Results showed that LIPO compared with CON infusion increased plasma triglyceride as well as free fatty acid and serotonin concentrations but reduced the proportion of de novo synthesized milk fatty acids (sum of C6 to C16). Daily CH4 production and DMI were lower, whereas daily CH4 yield (CH4/DMI) was greater in LIPO than CON cows, although CH4 yield decreased from d 1 to d 2 by 2 to 14% in LIPO-infused cows only. This effect was associated with a higher (acetate + butyrate)/propionate ratio, tending lower propionate concentrations between 24 and 34 h of infusion, reduced relative abundances of genera belonging to Succinivibrio, Ruminococcaceae, and Ruminiclostridium, and greater relative Bacteroidetes genus abundances in the rumen.

    更新日期:2018-03-29
  • Low colostrum yield in Jersey cattle and potential risk factors
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    K. Gavin, H. Neibergs, A. Hoffman, J.N. Kiser, M.A. Cornmesser, S. Amirpour Haredasht, B. Martínez-López, J.R. Wenz, D.A. Moore

    Consumption of an adequate volume of high-quality colostrum is vital to a dairy calf's ability to survive and become a productive herd member. However, some dairy herds have reported a deficiency of colostrum production, which ranges from a low volume to no colostrum produced, by cows during fall and winter. Little information regarding this phenomenon exists. The purpose of this study was to characterize the syndrome and identify potential risk factors for low colostrum yield. A 2,500-cow Jersey dairy farm was enrolled in a prospective cohort study in May 2016, to evaluate possible effects of photoperiod, temperature, and cow factors on colostrum production. Dairy personnel were trained to collect, weigh, and evaluate colostrum quality. Information on parity, previous lactation length, previous 305-d mature equivalent milk production, and dry period length were collected through the farm's dairy management software. Weather and photoperiod data were also collected. Over the year of enrollment, 2,988 eligible cows calved and had colostrum weights recorded and 38% were primiparous (n = 1,143), 25% were in their second lactation (n = 752), and 37% were in their third or greater lactation (n = 1,093). The overall average colostrum yield was 6.6 kg/cow in June 2016, 2.5 kg/cow in December 2016, and 4.8 kg/cow in May 2017. Multiparous cows had a larger decline in colostrum production between June and December (6.6 to 1.3 kg/cow) compared with primiparous animals (6.5 to 4.2 kg/cow). Overall, average colostrum production decreased by 0.17 kg/cow per week during this time, 0.22 kg for multiparous cows and 0.08 kg for primiparous cows. A logistic regression model was constructed for all cows to evaluate effects of cow factors on low colostrum production (<2.7 kg at first milking). Dry period length, calf sex, singleton or twin, age at freshening, month of calving and previous lactation length were significantly associated with the probability of low colostrum yield (<2.7 kg at first milking). A cross-correlation function analysis between the time series for colostrum yield and photoperiod revealed a high correlation at the time of calving and 1 mo prior, particularly for multiparous cows. A pedigree analysis showed that extreme colostrum yield (low vs. high) followed some sire lines. Low colostrum production in this herd could have an economic effect on the dairy and calf health and appears to have a strong seasonal and, potentially, a genetic component.

    更新日期:2018-03-29
  • Comparison of adhesion characteristics of common dairy sporeformers and their spores on unmodified and modified stainless steel contact surfaces
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    Shivali Jindal, Sanjeev Anand

    The attachment of aerobic spore-forming bacteria and their spores to the surfaces of dairy processing equipment leads to biofilm formation. Although sporeformers may differ in the degree of attachment, various surface modifications are being studied in order to develop a surface that is least vulnerable to attachment. This study was conducted to compare the extent of adhesion of spores and vegetative cells of the thermotolerant sporeformer Bacillus licheniformis and the high-heat-resistant sporeformers Geobacillus stearothermophilus and Bacillus sporothermodurans on both native and modified stainless steel surfaces. We studied the effect of contact surface and cell surface properties (including surface energy, surface hydrophobicity, cell surface hydrophobicity, and zeta potential) on the adhesion tendency of both types of sporeformers and their spores. Attachment to native and modified (Ni-P-polytetrafluoroethylene, Ni-P-PTFE) stainless steel surfaces was determined by allowing interaction between the respective contact surface and vegetative cells or spores for 1 h at ambient temperature. The hydrophobicity of vegetative cells and spores of aerobic spore-forming bacteria was determined using the hexadecane assay, and zeta potential was determined using the Zeta sizer Nano series instrument (Malvern Panalytical, Malvern, UK). The results indicated a higher adhesion tendency of spores over vegetative cells for both thermotolerant and high-heat-resistant sporeformers. On comparing the sporeformers, B. sporothermodurans demonstrated the highest adhesion tendency followed by G. stearothermophilus; B. licheniformis exhibited minimal attachment on both surfaces. The tendency to adhere varied with cell surface properties, decreasing with lower cell surface hydrophobicity and higher cell surface charge. On the other hand, modifying contact surface properties for higher surface hydrophobicity and lower surface energy decreased attachment.

    更新日期:2018-03-29
  • Effects of methionine plus cysteine inclusion on performance and body composition of liquid-fed crossbred calves fed a commercial milk replacer and no starter feed
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    J.C.C. Chagas, M.A. Ferreira, A.P. Faciola, F.S. Machado, M.M. Campos, M.R. Entjes, J.L. Donzele, M.I. Marcondes

    This experiment aimed to evaluate the effects of supplying 4 different inclusion levels of Met + Cys to crossbred liquid-fed calves on animal performance and body composition. Thirty-six Holstein-Gyr male calves were separated into 2 age groups: 16 calves, slaughtered at an age of 30 d, representing the physiological phase from 8 to 30 d, and 20 calves, slaughtered at an age of 60 d, representing the physiological phase from 30 to 60 d. At 8 d of age, the animals were randomly distributed among the experimental treatments: 4 Met + Cys inclusion levels (Met + Cys: 8.0, 8.7, 9.4, and 10.2 g/d), provided by an AA supplement added to 1.0 kg (as fed) of commercial milk replacer containing soy protein concentrate and wheat protein isolate reconstituted at 13.8% (dry matter basis). The diet was supplied without allowing leftovers and no starter feed was provided. The experimental diets were supplied without allowing orts, so that the dry matter, crude protein, and ether extract intakes were the same for all animals, independent of Met + Cys level. Total weight gain, average daily gain, gain composition, and body composition were evaluated for both age groups separately. Digestibility of organic matter, crude protein, and ether extract was lower for 8 to 30 d than for 30 to 60 d. The effect of Met + Cys levels on the digestibility of nutrients was not observed; there also was no significant interaction between physiological phase and Met + Cys levels. For the 8 to 30 d group, no responses in performance were observed according to the different Met + Cys levels, which indicates that 8.0 g/d of Met + Cys met the requirements for this physiological phase. The 30 to 60 d group responded positively to higher Met + Cys inclusion in the diet. In conclusion, an optimal Met + Cys dietary level to ensure best performance and protein gain ranges from 8.41 to 9.81 g/d.

    更新日期:2018-03-29
  • Short communication: Chemical-sensory and volatile compound characterization of ricotta forte, a traditional fermented whey cheese
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    M. Faccia, A. Trani, G. Natrella, G. Gambacorta

    Ricotta forte is a traditional whey cheese, obtained through natural fermentation of fresh ricotta, that is getting increasing attention by food traders. In view of possible initiatives for its valorization, the chemical and sensory characteristics were investigated. Samples were obtained from 14 different manufacturer, and were subjected to chemical, biochemical, volatile organic compound, and sensory analyses. All samples presented low pH with high moisture (62–66%) and fat content (57–60% on dry matter). From a biochemical point of view, the electrophoretic patterns evidenced that β-lactoglobulin was the main protein present at all sample ages. Only intermediate levels of proteolysis (20.69% ripening index) took place during aging, whereas the main biochemical event in this dairy product was lipolysis (2.10 mEq/g of acid degree value). Accordingly, free fatty acids dominated the volatile organic compound profile and strongly influenced the sensory characteristics with flavor described as rancid, pungent, acrid, and smelly feet: all associated with short-chain fatty acids such as acetic, propionic, butyric, and caproic. Finally, the sample age did not influence chemical composition, whereas it had significant effect on lipolysis and flavor intensity.

    更新日期:2018-03-29
  • Characteristics of quinolone-resistant Escherichia coli isolated from bovine mastitis in China
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    Feng Yang, Shidong Zhang, Xiaofei Shang, Ling Wang, Hongsheng Li, Xurong Wang

    Escherichia coli is the leading causative agent of bovine mastitis worldwide. Quinolone-resistant E. coli is becoming a potential threat to veterinary and public health. The aim of this study was to investigate the characteristics of quinolone-resistant E. coli isolated from bovine mastitis cases in China. Antimicrobial susceptibility of the isolates against 15 antimicrobial agents was determined by disc diffusion method. Phylogenetic grouping was detected by PCR. Extended-spectrum β-lactamase-producing isolates were determined by double-disc synergy test. In addition, the plasmid-mediated quinolone resistance (PMQR) and β-lactamase-encoding genes, as well as mutations of quinolone resistance-determining regions in GyrA, GyrB, ParC, and ParE, were measured by PCR and DNA sequencing. Overall, 75 (22.9%) out of 328 E. coli isolates were confirmed as ciprofloxacin-resistant from 2,954 mastitic milk samples. Phylogenetic group analysis showed that the majority of these strains belonged to phylogenetic group A (57.3%) and group B1 (24.0%). All the resistant isolates were identified as multidrug resistant, showing high resistance to cephalosporins and non-β-lactams. Forty-nine (65.3%) of the quinolone-resistant isolates were positive for PMQR genes; aac-(6')-Ib-cr was the most common PMQR determinant detected in 33 (44.0%) isolates. Eighteen (24.0%), 4 (5.3%), 3 (4.0%), and 1 (1.3%) of the quinolone-resistant isolates were harboring oqxA/B, qepA4, qnrS, and qnrB2, respectively. Additionally, 55 (73.3%) of the quinolone-resistant E. coli isolates were found to be extended-spectrum β-lactamase producers. The preponderant β-lactamase-encoding gene, blaTEM, was detected in 44 (58.7%) isolates; blaCTX-M, blaCMY, and blaSHV were found in 35 (46.7%), 22 (29.3%), and 2 (2.7%) isolates, respectively. Moreover, the most frequently identified substitutions were S83L/D87N or S83L in GyrA, detected in all of the quinolone-resistant isolates. Meanwhile, 74 (98.7%), 33 (44.0%), and 6 (8.0%) of the isolates were carrying substitutions S80I in ParC, S458A in ParE, and S492N in GyrB, respectively. All 58 (77.3%) isolates with a high level of ciprofloxacin resistance (>32 µg/mL) carried single or double mutations in GyrA combined with single mutation in ParC. To the best of our knowledge, this is the first report on the high occurrence of PMQR determinants and quinolone-determining resistant regions mutations in quinolone-resistant E. coli isolated from bovine mastitis in China.

    更新日期:2018-03-29
  • The effect of using cow genomic information on accuracy and bias of genomic breeding values in a simulated Holstein dairy cattle population
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    E. Dehnavi, S. Ansari Mahyari, F.S. Schenkel, M. Sargolzaei

    Using cow data in the training population is attractive as a way to mitigate bias due to highly selected training bulls and to implement genomic selection for countries with no or limited proven bull data. However, one potential issue with cow data is a bias due to the preferential treatment. The objectives of this study were to (1) investigate the effect of including cow genotype and phenotype data into the training population on accuracy and bias of genomic predictions and (2) assess the effect of preferential treatment for different proportions of elite cows. First, a 4-pathway Holstein dairy cattle population was simulated for 2 traits with low (0.05) and moderate (0.3) heritability. Then different numbers of cows (0, 2,500, 5,000, 10,000, 15,000, or 20,000) were randomly selected and added to the training group composed of different numbers of top bulls (0, 2,500, 5,000, 10,000, or 15,000). Reliability levels of de-regressed estimated breeding values for training cows and bulls were 30 and 75% for traits with low heritability and were 60 and 90% for traits with moderate heritability, respectively. Preferential treatment was simulated by introducing upward bias equal to 35% of phenotypic variance to 5, 10, and 20% of elite bull dams in each scenario. Two different validation data sets were considered: (1) all animals in the last generation of both elite and commercial tiers (n = 42,000) and (2) only animals in the last generation of the elite tier (n = 12,000). Adding cow data into the training population led to an increase in accuracy (r) and decrease in bias of genomic predictions in all considered scenarios without preferential treatment. The gain in r was higher for the low heritable trait (from 0.004 to 0.166 r points) compared with the moderate heritable trait (from 0.004 to 0.116 r points). The gain in accuracy in scenarios with a lower number of training bulls was relatively higher (from 0.093 to 0.166 r points) than with a higher number of training bulls (from 0.004 to 0.09 r points). In this study, as expected, the bull-only reference population resulted in higher accuracy compared with the cow-only reference population of the same size. However, the cow reference population might be an option for countries with a small-scale progeny testing scheme or for minor breeds in large counties, and for traits measured only on a small fraction of the population. The inclusion of preferential treatment to 5 to 20% of the elite cows led to an adverse effect on both accuracy and bias of predictions. When preferential treatment was present, random selection of cows did not reduce the effect of preferential treatment.

    更新日期:2018-03-29
  • Nuclear factor-like factor 2-antioxidant activation through the action of ataxia telangiectasia-mutated serine/threonine kinase is essential to counteract oxidative stress in bovine mammary epithelial cells
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    Y.F. Ma, Z.H. Wu, M. Gao, J.J. Loor

    Nuclear factor (erythroid-derived 2)-like factor 2 (NFE2L2, formerly Nrf2) is a transcription factor that binds to the antioxidant response element (ARE) in the upstream promoter region of various antioxidant-responsive genes. Hence, at least in nonruminants, the NFE2L2-ARE signaling pathway plays an important role in the cellular antioxidant defense system. Whether oxidative stress in bovine mammary epithelial cells alters NFE2L2 or the NFE2L2-ARE pathway is unclear. Therefore, the objective of this study was to examine the response in NFE2L2- and NFE2L2-ARE-related components in bovine mammary epithelial cells (BMEC) under oxidative stress. An in silico analysis to identify potential phosphorylation sites on NFE2L2 and the protein kinases was performed with Netphos 3.1 (http://www.cbs.dtu.dk/services/NetPhos/) and Scansite (http://scansite.mit.edu) software. Isolated BMEC were exposed to H2O2 (600 μM) for 6 h to induce oxidative stress. In silico analysis revealed ataxia telangiectasia-mutated (ATM) serine/threonine kinase as a key kinase responsible for the phosphorylation of NFE2L2. Thus, after the 6 h incubation with H2O2, BMEC were transiently transfected with ATM-small interfering RNA (siRNA) 1, 2, or 3. Compared with the control, transfection with ATM-siRNA3 resulted in proliferation rates that were 60.7 and 36.2% lower with or without H2O2. In addition, production of reactive oxygen species and malondialdehyde increased markedly, but activities of superoxide dismutase, glutathione peroxidase, catalase, and glutathione-S-transferase decreased markedly in transfected cells without or with H2O2 compared with the control. Transfected cells had markedly lower protein and mRNA expression of NFE2L2 without or with H2O2 compared with the control. In addition, fluorescent activity of the ARE in transfected BMEC indicated that NFE2L2-driven transcriptional activation decreased under oxidative stress. Overall, results indicate that ATM is a physiologically relevant NFE2L2 kinase. Furthermore, inhibition of ATM activity can cause marked alterations in oxidative stress leading to cell death as a result of diminished capacity of BMEC to cope with H2O2-induced cytotoxicity. The relevance of this kinase in vivo merits further study.

    更新日期:2018-03-29
  • Symposium review: Amino acid uptake by the mammary glands: Where does the control lie?
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-28
    John P. Cant, Julie J.M. Kim, Scott R.L. Cieslar, John Doelman

    Milk protein yield responses to changes in the profile of essential amino acids absorbed by the gastrointestinal tract or circulating in blood plasma do not follow the classic limiting amino acid response, in part because of an ability of the mammary glands to modify their blood flow rate and net clearance of amino acids out of plasma. The hypothesis that mammary blood flow is locally regulated to maintain ATP balance accounts for observed changes in flow due to postruminal glucose, insulin, and essential amino acid (EAA) infusions. An additional hypothesis that net mammary uptakes of metabolites from blood are affected by perturbations in their respective arterial concentrations and the rate of mammary blood flow also appears to hold for the energy metabolites glucose, acetate, β-hydroxybutyrate, and fatty acids. However, net EAA uptakes by the mammary glands are poorly predicted by models considering arterial concentrations and blood flow rates only. Evidence points to intramammary protein synthesis and secretion as the determinant of net EAA uptake. The intracellular signaling network anchored by the mechanistic target of rapamycin complex 1 stands as an excellent candidate to explain nutritional effects on milk protein synthesis because it integrates information on physiological and nutritional state to affect protein synthesis and cell metabolism, growth, proliferation, and differentiation in many cell types. In mammary cells in vitro and in vivo, the mechanistic target of rapamycin complex 1, integrated stress response, and glycogen synthase kinase-3 networks that contribute to regulation of initiation of mRNA translation are responsive to acute changes in nutrient supply and EAA profile. However, after several days of postruminal infusion of balanced and imbalanced EAA profiles, these signaling networks do not appear to continue to account for changes in milk protein yields. Gene expression evidence suggests that regulation of components of the unfolded protein response that control biogenesis of the endoplasmic reticulum and differentiation of a secretory phenotype may contribute to effects of nutrition on milk protein yield. Connections between early signaling events and their long-term consequences should be sought.

    更新日期:2018-03-29
  • Comparison of effects of routine topical treatments in the milking parlor on digital dermatitis lesions
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    C. Jacobs, K. Orsel, S. Mason, W. Barkema

    Digital dermatitis (DD), an infectious bacterial disease affecting the feet of dairy cattle, can cause lameness and decrease milk production, fertility, and animal welfare. Current DD treatment typically involves routine hoof trimming and topical antibiotics. Several nonantibiotic commercial topical products are used for controlling DD lesions; however, there is limited or no evidence regarding their effectiveness. The objectives of this study were to evaluate 2 commercially available topical applications on their ability to (1) clinically cure active DD lesions to nonactive lesions and (2) prevent recurrence of active DD lesions. Ten farms were visited weekly. In the milking parlor, the hind feet of lactating cattle were cleaned and scored (M-stage scoring system). Cattle with DD lesions at the first visit were randomly allocated to 1 of 4 treatment groups: positive control (tetracycline solution), HealMax (AgroChem Inc., Saratoga Springs, NY), HoofSol (Diamond Hoof Care Ltd., Intracare BV, Veghel, the Netherlands), and a negative control (saline). All products were applied to lesions using a spray bottle. Tetracycline, HealMax, and HoofSol had a higher probability of clinical cure for active lesions compared with saline 1 wk after the first treatment (wk 1), with 69, 52, and 79% clinical cure of active lesions, respectively, compared with 34% with saline. At wk 7, the probability of clinical cure for active lesions was 10, 33, 31, and 45% of lesions treated weekly with saline, tetracycline, HealMax, and HoofSol, respectively (no difference among treatments). The substantial clinical cure with saline highlighted the potential importance of cleaning feet. In wk 1, treatment with saline, tetracycline, HealMax, and HoofSol resulted in a probability of recurrence of active DD lesions of 9, 11, 11, and 8%, respectively, with no product being superior to saline. After 7 wk, the probability of recurrence of active lesions was 5, 7, 6, and 6% for saline, tetracycline, HealMax, and HoofSol respectively, with no difference among groups in wk 7. These results provide alternatives to antibiotics for treatment of DD lesions and highlight the potential importance of cleaning feet in the milking parlor.

    更新日期:2018-03-22
  • Differing genetic trend estimates from traditional and genomic evaluations of genotyped animals as evidence of preselection bias in US Holsteins
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    Y. Masuda, P.M. VanRaden, I. Misztal, T.J. Lawlor

    The objective of this study was to compare genetic trends from single-step genomic BLUP (ssGBLUP) and traditional BLUP models for milk production traits of US Holsteins. Phenotypes were 305-d milk, fat, and protein yields from 21,527,040 cows recorded between January 1990 and August 2015. The pedigree file included 29,651,623 animals and was limited to 3 generations back from recorded or genotyped animals. Genotypes for 764,029 animals were used, and analyses were by a 3-trait repeatability model as used in the US official genetic evaluation. Unknown-parent groups were incorporated into the inverse of a relationship matrix (H−1 in ssGBLUP and A−1 in BLUP) with the QP transformation. For ssGBLUP, 18,359 genotyped animals were randomly chosen as core animals to calculate the inverse of the genomic relationship matrix with the APY algorithm. Computations took 6.5 h and 1.4 GB of memory for BLUP, and 13 h and 115 GB of memory for ssGBLUP. For genotyped sires with at least 10 daughters, the average genetic levels for predicted transmitting ability (PTA) and genomic PTA were similar up to 2008, with a higher level for ssGBLUP later (approximately by 36 kg for milk, 2.1 kg for fat, and 1.1 kg for protein for bulls born in 2010). For genotyped cows, the average genetic levels were similar up to 2006, with a higher level for ssGBLUP (approximately by 91 kg for milk, 3.6 kg for fat, and 2.7 kg for protein for cows born in 2012). For all cows, the average levels were slightly higher for ssGBLUP, with much smaller differences than for genotyped cows. Trends for BLUP indicate bias due to genomic preselection for genotyped sires and cows. For official evaluations released in December 2016, traditional PTA had the same trend as multiple-step genomic PTA for both genotyped bulls and cows except for the youngest bulls, who had traditional PTA slightly lower than genomic PTA. For genotyped bulls born in recent years, genetic gain for official traditional and genomic evaluations was similar in contrast to ssGBLUP and BLUP differences. Official PTA for cows were adjusted so that the Mendelian sampling variance was comparable with that for bulls, and those adjustments likely removed bias due to genomic preselection from traditional PTA, especially for genotyped cows. The ssGBLUP method seems to account partially for that bias and is computationally suitable for national evaluations.

    更新日期:2018-03-22
  • Elimination of experimentally induced bovine intramammary infection assessed by multiplex real-time PCR and bacterial culture
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    Heidi Hiitiö, Satu Pyörälä, Suvi Taponen, Päivi Rajala-Schultz, Heli Simojoki

    Diagnosis of bovine intramammary infection (IMI) has traditionally been based on bacterial culture, but currently IMI can also be detected with DNA based methods, such as multiplex real-time PCR. The aim of this study was to describe the elimination of bacteria in experimentally induced IMI on the quarter level, using conventional bacterial culture (BC) and multiplex real-time PCR. Two coagulase-negative staphylococcal species, Staphylococcus epidermidis and Staphylococcus simulans, were experimentally inoculated into 14 healthy quarters of 8 dairy cows during 4 consecutive study periods. Intramammary infections were followed with 20 milk samplings per each quarter. Milk somatic cell count was monitored to evaluate the inflammation process in the quarters. Four quarters cured spontaneously during the study period according to the culture. The PCR detected staphylococcal DNA from these quarters for several days after they were defined as cured in BC. Agreement between BC and PCR results varied from substantial to almost perfect agreement for the first 36 h postchallenge, decreasing to moderate levels toward the end of the sampling period. Based on this study, we recommend collecting possible follow-up samples to assess the bacteriological cure from IMI not until 2 to 3 wk after the onset of mastitis or after the quarter milk somatic cell count has normalized when PCR is used.

    更新日期:2018-03-22
  • Hunter versus CIE color measurement systems for analysis of milk-based beverages
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    Ni Cheng, David M. Barbano, Mary Anne Drake

    The objective of our work was to determine the differences in sensitivity of Hunter and International Commission on Illumination (CIE) methods at 2 different viewer angles (2 and 10 degrees) for measurement of whiteness, red/green, and blue/yellow color of milk-based beverages over a range of composition. Sixty combinations of milk-based beverages were formulated (2 replicates) with a range of fat level from 0.2 to 2%, true protein level from 3 to 5%, and casein as a percent of true protein from 5 to 80% to provide a wide range of milk-based beverage color. In addition, commercial skim, 1 and 2% fat high-temperature, short-time pasteurized fluid milks were analyzed. All beverage formulations were HTST pasteurized and cooled to 4°C before analysis. Color measurement viewer angle (2 versus 10 degree) had very little effect on objective color measures of milk-based beverages with a wide range of composition for either the Hunter or CIE color measurement system. Temperature (4, 20, and 50°C) of color measurement had a large effect on the results of color measurement in both the Hunter and CIE measurement systems. The effect of milk beverage temperature on color measurement results was the largest for skim milk and the least for 2% fat milk. This highlights the need for proper control of beverage serving temperature for sensory panel analysis of milk-based beverages with very low fat content and for control of milk temperature when doing objective color analysis for quality control in manufacture of milk-based beverages. The Hunter system of color measurement was more sensitive to differences in whiteness among milk-based beverages than the CIE system, whereas the CIE system was much more sensitive to differences in yellowness among milk-based beverages. There was little difference between the Hunter and CIE system in sensitivity to green/red color of milk-based beverages. In defining milk-based beverage product specifications for objective color measures for dairy product manufacturers, the viewer angle, color measurement system (CIE vs. Hunter), and sample measurement temperature should be specified along with type of illuminant.

    更新日期:2018-03-22
  • Effects of homolactic bacterial inoculant on the performance of lactating dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    J.L.P. Daniel, O.C.M. Queiroz, K.G. Arriola, R. Daetz, F. Basso, J.J. Romero, A.T. Adesogan

    The objective of this experiment was to determine the effect of applying a homofermentative bacterial inoculant to corn silage on the performance of dairy cows. After harvesting, corn forage was treated with nothing (CON) or with an inoculant containing a mixture of Lactococcus lactis, Lactobacillus plantarum, and Enterococcus faecium at 1.5 × 105 cfu/g of fresh forage (MC; SiloSolve MC, Chr. Hansen A/S, Hørsholm, Denmark). After 186 d of storage in Ag-Bags (A Miller-St. Nazianz Inc., St. Nazianz, WI), silages were fed as part of a total mixed ration containing 55% concentrates, 10% alfalfa hay, and 35% CON or MC corn silage. Sixty early-lactation Holstein dairy cows (30 multiparous and 30 primiparous) housed in a freestall barn with Calan gates (American Calan Inc., Northwood, NH) were assigned to the dietary treatments from 20 to 100 d in milk. Silage inoculated with MC had a more homofermentative pattern evidenced by greater lactic acid concentration (3.83 vs. 4.48% of DM) and lower concentrations of acetic (2.34 vs. 1.68% of DM) and propionic (0.37 vs. 0.10% of DM) acids and ammonia (9.11 vs. 7.82% of N) for CON and MC, respectively. Dry matter intake (23.1 vs. 23.2 kg/d) did not differ among treatments, but the MC silage had greater apparent digestibility of DM (68.8 vs. 70.8%), which led to greater yields of milk (37.7 vs. 38.5 kg/d), fat-corrected milk (37.6 vs. 38.4 kg/d), milk fat (1.30 vs. 1.33 kg/d), and lactose (1.83 vs. 1.92 kg/d) for CON and MC cows, respectively. Milk from cows fed MC silage had higher lactose (4.86 vs. 4.93%), lower protein (2.93 vs. 2.83%), and similar contents of fat (3.47 vs. 3.44%) compared with CON cows. Feed efficiency (fat-corrected milk/dry matter intake) was not affected by treatment (1.69 vs. 1.72 for CON and MC, respectively). Inoculation of corn silage with the homofermentative inoculant increased digestibility of the total mixed ration and increased milk yield by lactating dairy cows.

    更新日期:2018-03-22
  • Metabotypes with elevated protein and lipid catabolism and inflammation precede clinical mastitis in prepartal transition dairy cows
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    F. Zandkarimi, J. Vanegas, X. Fern, C.S. Maier, G. Bobe

    Clinical mastitis (CM), the most prevalent and costly disease in dairy cows, is diagnosed most commonly shortly after calving. Current indicators do not satisfactorily predict CM. This study aimed to develop a robust and comprehensive mass spectrometry-based metabolomic and lipidomic workflow using untargeted ultra-performance liquid chromatography high-resolution mass spectrometry for predictive biomarker detection. Using a nested case-control design, we measured weekly during the prepartal transition period differences in serum metabolites, lipids, inflammation markers, and minerals between clinically healthy Holstein dairy cows diagnosed with mastitis postcalving (CMP; n = 8; CM diagnosis d 1 = 3 cows, d 2 = 2 cows, d 4 = 1 cow; d 25 = 1 cow, and d 43 = 1 cow that had subclinical mastitis since d 3) or not (control; n = 9). The largest fold differences between CMP and control cows during the prepartal transition period were observed for 3′-sialyllactose in serum. Seven metabolites (N-methylethanolamine phosphate, choline, phosphorylcholine, free carnitine, trimethyl lysine, tyrosine, and proline) and 3 metabolite groups (carnitines, AA metabolites, and water-soluble phospholipid metabolites) could correctly classify cows for their future CM status at both 21 and 14 d before calving. Biochemical analysis using lipid and metabolite-specific commercial diagnostic kits supported our mass spectrometry-based omics results and additionally showed elevated inflammatory markers (serum amyloid A and visfatin) in CMP cows. In conclusion, metabolic phenotypes (i.e., metabotype) with elevated protein and lipid metabolism and inflammation may precede CM in prepartal transition dairy cows. The discovered serum metabolites and lipids may assist in predictive diagnostics, prevention strategies, and early treatment intervention against CM, and thereby improve cow health and welfare.

    更新日期:2018-03-22
  • Milk nutrition and childhood epilepsy: An ex vivo study on cytokines and oxidative stress in response to milk protein fractions
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    M. Albenzio, A. Santillo, M.G. Ciliberti, L. Figliola, M. Caroprese, A.N. Polito, G. Messina

    We present a pilot study on the effects of milk protein fractions [αS1-casein (CN), αS2-CN, κ-CN, β-CN, and a mix of α-lactalbumin (α-LA) and β-lactoglobulin (β-LG)] from different animal species (bovine, ovine, and caprine) on pro- and anti-inflammatory cytokines and oxidative status in cultured peripheral blood mononuclear cells from children with generalized epilepsy. Peripheral blood mononuclear cells (PBMC) were obtained by density gradient from blood of 10 children with generalized epilepsy (5 males; mean age 33.6 ± 5.4 mo) and 10 controls (5 males; mean age 35.6 ± 6.8 mo). Children with epilepsy were grouped according to cytokine levels as follows: children with epilepsy having low levels of cytokines not different from those of control children (LL-EC); children with epilepsy having cytokine levels at least 5-fold higher (medium levels) than those of control children (ML-EC); and children with epilepsy having cytokine levels at least 10-fold higher (high levels) than those of control children (HL-EC). The production of tumor necrosis factor-α (TNF-α), IL-10, IL-6, and IL-1β was studied in cultured PBMC incubated with αS1-CN, αS2-CN, κ-CN, β-CN, and a mix of α-LA and β-LG from bovine, caprine, and ovine milks. The levels of reactive oxygen and nitrogen species (ROS/RNS) and catalase activity were assessed in cultured supernatant. In the HL-EC group, β-CN from small ruminant species (ovine and caprine) induced the highest levels of TNF-α, whereas PBMC incubated with αS2-CN from ovine milk and the mix of β-LG and α-LA from all tested milk species had the lowest levels of TNF-α. Within the HL-EC group, production of IL-1β was higher for bovine and ovine αS2-CN fractions and lower for caprine and ovine β-CN and κ-CN. In the HL-EC group, IL-6 was higher in cultured PBMC incubated with αS2-CN from bovine and ovine milk than from caprine milk. The cytokine IL-10 did not differ among milking species. The highest levels of ROS/RNS were found after incubation of PBMC with the β-CN fraction in bovine milk. Catalase activity was higher in PBMC cultured with β-CN isolated from bovine and caprine milk and with αS1-CN from ovine milk.

    更新日期:2018-03-22
  • Bifidobacterium bifidum YIT 10347 fermented milk exerts beneficial effects on gastrointestinal discomfort and symptoms in healthy adults: A double-blind, randomized, placebo-controlled study
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    A. Gomi, K. Yamaji, O. Watanabe, M. Yoshioka, K. Miyazaki, Y. Iwama, Y. Urita

    In a preliminary open-label trial by our group, Bifidobacterium bifidum YIT 10347 (YIT10347) relieved gastric symptoms in patients with functional gastrointestinal disorders. Hence, in this study, we investigated the effects of YIT10347 on gastrointestinal symptoms in healthy adults. In this prospective double-blind, randomized, placebo-controlled trial (UMIN000024654), 100 healthy Japanese adults were randomly assigned to a YIT10347 group or placebo group and consumed 100 mL of YIT10347-fermented milk or placebo fermented milk, respectively, every day for 4 wk. Gastrointestinal symptoms were evaluated by using the modified Frequency Scale for Symptoms of Gastroesophageal Reflux Disease (m-FSSG) and Gastrointestinal Symptom Rating Scale (GSRS) as primary endpoints. Mental symptoms, quality of life, salivary stress markers, and gastric emptying were evaluated as secondary endpoints. Effectiveness and safety were analyzed in a per-protocol set (YIT10347 group, n = 39; placebo group, n = 40) and full analysis set (YIT10347 group, n = 50; placebo group, n = 50), respectively. In the m-FSSG evaluation, the YIT10347 group had a significantly higher relief rate of postprandial discomfort and greater changes in postprandial epigastric pain score from baseline than the placebo group. In the GSRS evaluation, the YIT10347 group had significantly higher relief rates of overall gastrointestinal symptoms, upper gastrointestinal symptoms, flatus, and diarrhea than the placebo group. We detected no significant differences in scores or relief rates of mental symptoms and quality of life, a salivary stress marker, or gastric emptying between the 2 groups. No severe adverse events associated with test beverage consumption were observed in either group. These findings suggest that daily consumption of YIT10347-fermented milk exerts beneficial effects on gastrointestinal discomfort and symptoms such as postprandial discomfort and epigastric pain in healthy adults.

    更新日期:2018-03-22
  • Short communication: The effect of novel antiseptic compounds on umbilical cord healing and incidence of infection in dairy calves
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    A.L. Fordyce, L.L. Timms, K.J. Stalder, H.D. Tyler

    The goal of dipping the umbilical cord after birth in calves is to promote healing of the umbilical stump, prevent infection, and encourage the umbilical tissue to detach from the body. Treatment applied to the umbilical area is an important management step for preventing morbidity and mortality in calves. The objective of this study was to compare the effect of 4 umbilical dips on the healing rate, incidence of infection, and age at umbilical cord detachment using newborn Holstein heifer calves (n = 73). Calves were alternately assigned by birth order to 4 treatment groups: 7% iodine, a dry dip formulated using an antibacterial peptide (nisin) mixed with talc (3.105 g of nisin per 100 g of talcum powder on a weight per weight basis), liquid nisin (64 µg/mL), and 4% chlorhexidine mixed with alcohol in a 50:50 solution. Umbilical cords were dipped 30 min after birth. Before initial dipping, umbilical cord diameter (as an indicator of the rate of cord drying and healing rate) was determined using a digital caliper. The caliper measurements were repeated at 24 ± 1, 48 ± 1, and 72 ± 1 h (±standard deviation) of age and were continued daily until the umbilical cord healed and detached from the animal's body. Diagnosed umbilical infections were documented by veterinary staff based on a combination of clinical symptoms (redness, swelling, purulent discharge, painful response (flinch or kicking) to palpation of the umbilical stump) in addition to a lack of appetite and fever. Data were analyzed using MIXED model procedures with fixed effect of umbilical treatment. No treatment differences were noted between dips on the umbilical cord drying rate or days for umbilical cord to detach. Treatment effects were observed on incidence of umbilical infection (incidence of infection for calves across all treatments was 9.0%).

    更新日期:2018-03-22
  • Nuclear factor erythroid 2-related factor 2 antioxidant response element pathways protect bovine mammary epithelial cells against H2O2-induced oxidative damage in vitro
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    Y.F. Ma, Z.H. Wu, M. Gao, J.J. Loor

    The experiment was conducted to determine the role of nuclear factor (erythroid-derived 2)-like factor 2 (NFE2L2, formerly Nrf2) antioxidant response element (ARE) pathway in protecting bovine mammary epithelial cells (BMEC) against H2O2-induced oxidative stress injury. An NFE2L2 small interfering RNA (siRNA) interference or a pCMV6-XL5-NFE2L2 plasmid fragment was transfected to independently downregulate or upregulate expression of NFE2L2. Isolated BMEC in triplicate were exposed to H2O2 (600 μM) for 6 h to induce oxidative stress before transient transfection with scrambled siRNA, NFE2L2-siRNA, pCMV6-XL5, and pCMV6-XL5-NFE2L2. Cell proliferation, apoptosis and necrosis rates, antioxidant enzyme activities, reactive oxygen species (ROS) and malondialdehyde (MDA) production, protein and mRNA expression of NFE2L2 and downstream target genes, and fluorescence activity of ARE were measured. The results revealed that compared with the control, BMEC transfected with NFE2L2-siRNA3 had proliferation rates that were 9 or 65% lower without or with H2O2, respectively. These cells also had apoptosis and necrosis rates that were 27 and 3.5 times greater with H2O2 compared with the control group, respectively. In contrast, transfected pCMV6-XL5-NFE2L2 had proliferation rates that were 64.3% greater or 17% lower without or with H2O2 compared with the control group, respectively. Apoptosis rates were 1.8 times lower with H2O2 compared with the control. In addition, compared with the control, production of ROS and MDA and activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and glutathione-S-transferase (GST) increased markedly in cells transfected with pCMV6-XL5-NFE2L2 and without H2O2. However, compared with the control, production of ROS and MDA and activity of CAT and GSH-Px increased markedly, whereas activities of SOD and GST decreased in cells transfected with pCMV6-XL5-NFE2L2 and incubated with H2O2. Compared with the control, cells transfected with NFE2L2-siRNA3 with or without H2O2 had lower production of ROS and MDA and activity of SOD, CAT, GSH-Px, and GST. Cells transfected with pCMV6-XL5-NFE2L2 with or without H2O2 had markedly higher protein and mRNA expression of NFE2L2, heme oxygenase-1 (HMOX-1), NADH quinone oxidoreductase 1, glutamate cysteine ligase catalytic subunit, and glutamyl cystine ligase modulatory subunit compared with the control incubations. Cells transfected with NFE2L2-siRNA3 without or with H2O2 had markedly lower protein and mRNA expression of NFE2L2, HMOX-1, NADH quinone oxidoreductase 1, glutamyl cystine ligase modulatory subunit, and glutamate-cysteine ligase catalytic subunit compared with the control incubations. In addition, expression of HMOX-1 was 5.3-fold greater with H2O2 compared with the control. Overall, results indicate that NFE2L2 plays an important role in the NFE2L2-ARE pathway via the control of HMOX-1. The relevant mechanisms in vivo merit further study.

    更新日期:2018-03-22
  • Genome-wide association mapping for type and mammary health traits in French dairy goats identifies a pleiotropic region on chromosome 19 in the Saanen breed
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    Pauline Martin, Isabelle Palhière, Cyrielle Maroteau, Virginie Clément, Ingrid David, Gwenola Tosser Klopp, Rachel Rupp

    Type traits and mammary health traits are important to dairy ruminant breeding because they influence animal health, milking ability, and longevity, as well as the economic sustainability of farms. The availability of the genomic sequence and a single nucleotide polymorphism chip in goats has opened up new fields of investigation to better understand the genes and mechanisms that underlie such complex traits and to be able to select them. Our objective was to perform a genome-wide association study in dairy goats for 11 type traits and somatic cell count (SCC) as proxies for mastitis resistance. A genome-wide association study was implemented using a daughter design composed of 1,941 Alpine and Saanen goats sired by 20 artificial insemination bucks, genotyped with the Illumina GoatSNP50 BeadChip (Illumina Inc., San Diego, CA). This association study was based on both linkage analyses and linkage disequilibrium using QTLmap software (http://dga7.jouy.inra.fr/qtlmap/) interval mapping was performed with the likelihood ratio test using linear regressions. Breeds were analyzed together and separately. The study highlighted 37 chromosome-wide significant quantitative trait loci (QTL) with linkage analyses and 222 genome-wide significant QTL for linkage disequilibrium, for type and SCC traits in dairy goats. Genomic control of those traits was mostly polygenic and breed-specific, suggesting that within-breed selection would be favored for those traits. Noteworthy, Capra hircus autosome (CHI) 19 appeared to be highly enriched in single nucleotide polymorphisms associated with type and SCC, with 2 highly significant regions in the Saanen breed. One region (33–42 Mb) was significantly associated with SCC and includes candidate genes associated with response to intramammary infections (RARA, STAT3, STAT5A, and STAT5B). Another region of the CHI 19 (24.5–27 Mb) exhibited an adverse pleiotropic effect on milk production (milk, fat yield, and protein yield) and udder traits (udder floor position and rear udder attachment) that agreed with the negative genetic correlations that exist between those 2 groups of traits. These QTL were not found in the Alpine breed. In Alpine, the 2 most significant regions were associated with chest depth on CHI 6 (45.8–46.0 Mb) and CHI 8 (80.7–81.1 Mb). These results will be helpful for goat selection in the future and could lead to identification of causal mutations.

    更新日期:2018-03-22
  • Evaluation of alternatives to cautery disbudding of dairy goat kids using physiological measures of immediate and longer-term pain
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    Melissa N. Hempstead, Joseph R. Waas, Mairi Stewart, Vanessa M. Cave, Mhairi A. Sutherland

    We evaluated alternatives to cautery disbudding of goat kids using physiological measures of immediate and longer-term pain. Fifty Saanen doe kids were randomly assigned to 1 of 5 treatments (n = 10/treatment): (1) cautery disbudding (CAUT), (2) caustic paste disbudding (CASP), (3) liquid nitrogen disbudding (CRYO), (4) clove oil injected into the horn bud (CLOV), or (5) sham disbudding (SHAM). Serum cortisol and haptoglobin concentrations were measured from blood samples collected immediately before treatment (baseline) and at 15, 30, 60, and 120 min and then again at 6 and 24 h post-treatment. An infrared thermography camera was used to take images of the horn buds 24 h pre- and 24, 48, and 72 h post-treatment to measure skin temperature. Body weight was measured daily for 1 wk to assess weight change post-treatment. Images of the horn buds were taken at d 1, 2, and 7 and at 6 wk post-treatment to assess tissue damage and wound healing. Mean cortisol concentrations were elevated in CASP kids 1 h post-treatment relative to CAUT kids. Cortisol concentrations of CRYO kids were higher than those of CAUT kids 30 min post-treatment; concentrations for CLOV kids were similar to CAUT kids post-treatment. Mean haptoglobin concentrations were similar across treatments over time; however, CLOV kids had higher concentrations at 24 h post-treatment than all other treatments. Skin temperatures of CASP and CLOV kids were elevated relative to CAUT kids at all time points post-treatment, and all disbudded kids had skin temperatures above those of SHAM kids at 72 h post-treatment. Treatment did not influence weight gain. The CAUT kids had large, open wounds exposing bone; small scabs were still evident 6 wk post-treatment. The CASP kids had red and open, raw wounds that generated large eschars, apparent for up to 6 wk. The CRYO kids had closed, dry wounds initially, but over time lesions appeared that caused open wounds; small scabs were present 6 wk post-treatment. The CLOV kids had closed, dry wounds with blackened skin; healed skin and minimal scabs were present 6 wk post-treatment. Caustic paste and cryosurgical disbudding appeared to cause more pain compared with cautery disbudding; thus, these methods may not provide good alternatives to cautery disbudding. Clove oil appeared to cause a similar pain response as cautery disbudding and smaller wounds with earlier tissue repair; this method shows promise as an alternative to cautery disbudding.

    更新日期:2018-03-22
  • Effects of gamma radiation on microbial, physicochemical, and structural properties of whey protein model system
    J. Dairy Sci. (IF 2.474) Pub Date : 2018-03-21
    X.B. Wang, C.N. Wang, Y.C. Zhang, T.T. Liu, J.P. Lv, X. Shen, M.R. Guo

    Gamma radiation has been used in food processing for many years, though it has certain effects on food components. Whey protein solutions (10%/30%, wt/vol) were treated with gamma radiation at various dosages (10–25 kGy) and evaluated for microbial changes in the solutions and physicochemical and structural changes of whey proteins. Whey protein solutions after gamma radiation showed substantially lower populations of all viable microorganisms than those of controls. The 10% whey protein solution treated at radiation of 20 or 25 kGy remained sterile for up to 4 wk at room temperature. Gamma radiation increased viscosity and turbidity and decreased soluble nitrogen of whey protein solutions compared to nonradiated control samples regardless of radiation dosage. Nonreducing sodium dodecyl sulfate-PAGE suggested that whey proteins under gamma radiation treatment formed aggregates with high molecular weights. Reducing sodium dodecyl sulfate-PAGE showed that disulfide bonds played a role in gamma radiation-induced whey protein cross-linking. Scanning and transmission electron microscopy micrographs exhibited large aggregates of whey proteins after gamma radiation treatment. Results suggested that gamma radiation could be applied to whey protein solution for purposes of reducing microbial counts and cross-linking protein molecules.

    更新日期:2018-03-22
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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