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Fertility traits of recipient cows raised in the Amazon biome
Livestock Science ( IF 1.8 ) Pub Date : 2020-06-12 , DOI: 10.1016/j.livsci.2020.104147
Jefferson Viana Alves Diniz , Renato Mesquita Peixoto , Laine Oliveira Silva , Marina Marie Bento Nogueira , Rosano Ramos de Freitas , Bárbara Loureiro , Rafael Augusto Satrapa , Eunice Oba

This study aimed to evaluate a correlation between environmental temperature-humidity index (THI), rectal temperature (RT) and plasmatic concentration of cortisol in pregnancy rates of recipient cows in the Amazon biome. Recipient cows (n = 235) were submitted to an estrus synchronization simplified P36 protocol for a Fixed-Time Embryo Transference (FTEF). Rectal temperature of recipient cows and ambient temperature, relative humidity (RH) and dry-bulb temperature ( °C) were recorded on day zero (D0), eight (D8) and 16 (D16) of the protocol. On D16, each recipient received an embryo after the confirmation of a corpus luteum. At this moment, a blood sample was collected and cortisol concentration was evaluated in the sample with radioimmunoassay. On D41 (D33 embryo), pregnancy diagnosis was assessed (PD). The yield rates of recipient cows and pregnancy after the protocol were 66.81% (151/226) and 35.76% (54/151), respectively. Cows that became pregnant presented lower means in RT, plasmatic cortisol and THI parameters (P < 0.05) in comparison to non-pregnant group. The percentage of pregnant cows at Day 41 was higher (P < 0.0001) for cows that had RT ≤ 39.1 °C in all the days analyzed (D0, D8 and D16). Likewise, cows that entered the chute area under a low THI (< 74) had better (P < 0.005) pregnancy rates when compared with cows that were at the chute under a higher THI. This was observed on the three days evaluated throughout the protocol. The correlation coefficient between cortisol, RT and THI was above 59%. In addition, cortisol was lower in the PG cows. In conclusion, THI, RT and cortisol level are directly related to pregnancy success. Furthermore, this study could validate the use of THI as an auxiliary tool to assess thermal comfort and stress, which may reflect in the pregnancy outcome of recipient cows in the Amazon biome.



中文翻译:

亚马逊生物群落中饲养的受牛的生育特征

这项研究旨在评估亚马逊生物群落中受孕牛的怀孕率中环境温度-湿度指数(THI),直肠温度(RT)和血浆皮质醇浓度之间的相关性。收件人奶牛(n = 235)提交给发情同步简化的P36协议以进行固定时间的胚胎移植(FTEF)。在实验方案的第零天(D0),第八天(D8)和第十六天(D16)记录受牛的直肠温度和环境温度,相对湿度(RH)和干球温度(°C)。在第16天,在黄体证实后,每个接受者都接受了胚胎。此时,收集血液样品并通过放射免疫测定法评估样品中的皮质醇浓度。在D41(D33胚胎)上,评估了妊娠诊断(PD)。方案后接受牛和妊娠的产率分别为66.81%(151/226)和35.76%(54/151)。怀孕的母牛的RT,血浆皮质醇和THI参数均值较低(P<0.05)与非妊娠组相比。在分析的所有天中(D0,D8和D16),RT≤39.1°C的母牛在第41天的怀孕母牛所占的百分比更高(P <0.0001)。同样,在低THI(<74)下进入斜道区域的奶牛更好(P与在较高THI下处于溜槽的母牛相比,怀孕率<0.005)。在整个方案中评估的三天内观察到了这一点。皮质醇,RT和THI之间的相关系数高于59%。另外,PG奶牛的皮质醇水平较低。总之,THI,RT和皮质醇水平与妊娠成功直接相关。此外,这项研究可以验证使用THI作为评估热舒适度和压力的辅助工具,这可能反映了亚马逊生物群落中受牛的妊娠结局。

更新日期:2020-06-12
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