A 2-yr study evaluated the growth and postvaccination immune response of beef calves born from heifers offered no supplementation or pre- and postpartum supplementation of sugarcane molasses + urea with or without methionine hydroxy analog (MHA). On day 0 of each year (57 ± 5 d prepartum), Brangus crossbred beef heifers (n = 36/yr; 20 to 22 mo of age) were stratified by their initial body weight (BW; 396 ± 24.1 kg) and body condition score (BCS; 5.6 ± 0.43) and randomly allocated into 1 of 12 bahiagrass (Paspalum notatum) pastures (3 heifers/pasture). Treatments were randomly assigned to pastures (4 pastures/treatment/yr) and consisted of no supplementation (NOSUP) and supplementation of sugarcane molasses + urea (7.2 kg of DM/heifer/wk) with (MOL+) or without (MOL-) fortification with 105 g/heifer/wk of MHA. Treatments were provided from 57 ± 5 d prepartum until 17 ± 5 d postpartum (day 0 to 74). On day 74, all heifer-calf pairs were combined and managed as a single group until the end of the breeding season (day 237). Calves were early weaned at 89 ± 5 d of age (day 147), limit-fed at 3.5% of BW (DM basis) in drylot until day 201, and vaccinated against respiratory disease pathogens on days 160 and 188. Prepartum BCS on day 44 did not differ (P = 0.26) between MOL+ and MOL- heifers but both groups had greater (P < 0.0001) BCS than NOSUP heifers. Plasma concentrations of l-methionine on day 44 were the greatest (P ≤ 0.04) for MOL+ heifers and did not differ (P = 0.40) between NOSUP vs. MOL- heifers. Calf birth BW did not differ (P = 0.13) among treatments. Calf average daily gain (ADG) from birth to day 201 did not differ (P ≥ 0.17) between MOL+ vs. MOL- calves, but both groups had greater (P ≤ 0.05) ADG from birth to day 201 than NOSUP calves. Calf postvaccination plasma concentrations of glucose, cortisol, and haptoglobin did not differ among treatments (P ≥ 0.13). However, plasma concentrations of IGF-1 on day 167 and the overall positive vaccine seroconversion did not differ (P ≥ 0.18) between MOL- and MOL+ calves, but both were greater (P ≤ 0.04) compared with NOSUP calves. Hence, maternal supplementation of sugarcane molasses + urea increased BCS at calving and offspring BW gain and response to vaccination against respiratory pathogens compared with no maternal supplementation. MHA inclusion into maternal supplements effectively increased maternal plasma l-methionine concentrations but did not enhance maternal BCS at calving and offspring growth and postvaccination immune response.

中文翻译：

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母体补充能量和蛋白质，但不补充蛋氨酸羟基类似物，可以增强受牛影响的牛肉后代的产后生长和对疫苗接种的反应。


一项为期两年的研究评估了未补充甘蔗糖蜜 + 尿素（含或不含蛋氨酸羟基类似物 (MHA)）或产前和产后补充甘蔗糖蜜 + 尿素的小母牛生下的肉牛犊的生长和疫苗接种后免疫反应。每年的第 0 天（产前 57 ± 5 天），Brangus 杂交小母牛（n = 36/年；20 至 22 月龄）根据其初始体重（体重；396 ± 24.1 kg）和身体状况进行分层评分（BCS；5.6 ± 0.43）并随机分配到 12 个 bahiagrass（雀稗）牧场中的 1 个（3 头小母牛/牧场）。处理被随机分配到牧场（4个牧场/处理/年），包括不补充（NOSUP）和补充甘蔗糖蜜+尿素（7.2公斤DM/小母牛/周），有（MOL+）或没有（MOL-）强化含 105 克/小母牛/周的 MHA。从产前 57 ± 5 天到产后 17 ± 5 天（第 0 天至第 74 天）提供治疗。在第 74 天，所有小母牛和小牛对都被合并并作为一个组进行管理，直到繁殖季节结束（第 237 天）。犊牛在 89 ± 5 日龄（第 147 天）早期断奶，在干燥处以体重的 3.5%（DM 基础）进行限制饲喂，直至第 201 天，并在第 160 天和第 188 天接种呼吸道疾病病原体疫苗。 44 MOL+ 和 MOL- 小母牛之间没有差异 (P = 0.26)，但两组的 BCS 均高于 NOSUP 小母牛 (P < 0.0001)。第 44 天，MOL+ 小母牛的 L-蛋氨酸血浆浓度最高 (P ≤ 0.04)，NOSUP 与 MOL- 小母牛之间没有差异 (P = 0.40)。不同处理之间，犊牛出生体重没有差异（P = 0.13）。 MOL+ 与 MOL- 犊牛从出生到第 201 天的平均日增重 (ADG) 没有差异 (P ≥ 0.17)，但两组从出生到第 201 天的 ADG 均高于 NOSUP 犊牛 (P ≤ 0.05)。 犊牛接种后血浆中葡萄糖、皮质醇和结合珠蛋白的浓度在不同处理之间没有差异（P ≥ 0.13）。然而，第 167 天的 IGF-1 血浆浓度和总体阳性疫苗血清转化在 MOL- 和 MOL+ 犊牛之间没有差异 (P ≥ 0.18)，但与 NOSUP 犊牛相比均较高 (P ≤ 0.04)。因此，与母体不补充相比，母体补充甘蔗糖蜜+尿素可增加产犊时的 BCS 和后代体重增加以及对呼吸道病原体疫苗接种的反应。母体补充剂中添加 MHA 可有效增加母体血浆 L-蛋氨酸浓度，但不会增强母体产犊时的 BCS、后代生长以及疫苗接种后的免疫反应。