Department of Animal Science, Universidade Federal de Viçosa, Peter Henry Rolfs Avenue, Viçosa, Minas Gerais, 36570-900, Brazil.
BMC Vet Res. 2021 Sep 25;17(1):311. doi: 10.1186/s12917-021-03019-0.
Metabolic profile evaluation is a tool widely used in ruminant nutrition as metabolic cues that relate nutrition to physiology. Metabolic and hormonal traits change during pre-partum and lactation according to parity in dairy cows, but studies of beef cows under grazing are scarce. The present study aimed to evaluate how metabolic and hormonal traits change over time, their relationship to performance, and determine if these factors differ according to the parity order of grazing beef cows. Thirty-six pregnant Nellore cows (12 nulliparous, 12 primiparous, and 12 multiparous) were used. The study started at 60 d prepartum until 203 d of lactation.
The initial body weight (BW) and final BW were higher for multiparous cows (P > 0.05). An interaction occurred between parity and day (P < .0001) for body condition score. Nulliparous and primiparous body condition score were reduced from - 60 prepartum to 30 postpartum, then stabilized 60 postpartum (P < 0.05), while multiparous maintained body condition score from - 60 days until 60 days postpartum (P > 0.05). Calf BW, final BW, and average daily gain did not differ between parities (P > 0.05). Effect of day (P < 0.05) was detected for non-esterified fatty acids, triglycerides, total cholesterol, LDL, VLDL, progesterone, and insulin. An interaction was observed between parity and days for glucose, HDL, β-hydroxybutyrate, creatinine and IGF-1 (P < 0.05). Parity affected serum urea nitrogen, total proteins, albumin, and globulins (P < 0.05). Parity and day relative to calving did not impact total T3 and T4 (P > 0.05).
Hormonal and metabolic profile is strongly influenced by the stage of lactation. Time effects (pre-partum and lactation period) were more pronounced in nulliparous since they displayed more unbalanced metabolic and hormonal traits and lowered BCS pre- and postpartum.
代谢谱评估是反刍动物营养中广泛使用的一种工具，它是将营养与生理联系起来的代谢线索。奶牛在产前和泌乳期根据胎次会发生代谢和激素特征的变化，但关于放牧肉牛的研究却很少。本研究旨在评估代谢和激素特征随时间的变化，及其与性能的关系，并确定这些因素是否因放牧肉牛的胎次顺序而不同。36 头怀孕的尼洛牛（12 头初产，12 头经产和 12 头多产）用于本研究。研究从产前 60 天开始，持续到泌乳期 203 天。
初产牛的初始体重（BW）和最终 BW 更高（P>0.05）。体况评分存在胎次和天数的交互作用（P<0.0001）。初产牛和经产牛的体况评分从产前 60 天的-60 降至产后 30 天的-30，然后在产后 60 天稳定（P<0.05），而多产牛从产前 60 天到产后 60 天保持体况评分（P>0.05）。犊牛 BW、最终 BW 和平均日增重在胎次之间没有差异（P>0.05）。非酯化脂肪酸、甘油三酯、总胆固醇、LDL、VLDL、孕酮和胰岛素的天数（P<0.05）有影响。葡萄糖、HDL、β-羟丁酸、肌酐和 IGF-1 的胎次和天数存在交互作用（P<0.05）。血清尿素氮、总蛋白、白蛋白和球蛋白受胎次的影响（P<0.05）。胎次和产犊日期对总 T3 和 T4 没有影响（P>0.05）。
激素和代谢谱受泌乳阶段的强烈影响。初产牛的时间效应（产前和泌乳期）更为明显，因为它们在产前和产后表现出更多代谢和激素特征的不平衡，体况评分更低。
