Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.
Animal. 2021 Feb;15(2):100089. doi: 10.1016/j.animal.2020.100089. Epub 2020 Dec 15.
In general, calf production occurs in less intensive systems. The limitation of nutrients during the gestation phase of beef cows can have negative impacts on the consequent productivity of females. Therefore, this study aimed to evaluate the effects of nutritional levels in the third trimester of pregnancy on the productive performance of beef cows kept in a natural pasture (NP). Eighty-three Charolais × Nelore cows were used, ranging in age from 4 to 12 years, which were divided according to their nutritional levels during the third trimester of pregnancy: NP, cows supplemented with 100% of their energy and protein requirements (SP100) and cows supplemented with 150% of their energy and protein requirements (SP150). The experimental design was completely randomized with three treatments and a varied number of repetitions. The SP100 and SP150 cows presented better body condition at calving (2.92 and 2.99 vs 2.81 points) and at the start of the breeding season (2.90 and 2.95 vs 2.80 points) than did NP cows. The nutritional level of the cows in the third trimester of gestation did not influence the blood metabolite concentrations. The plasma levels of albumin and total proteins were 3.11 and 8.18 g/dl, respectively. Glucose and cholesterol showed values of 74.96 and 166.50 mg/dl. The lowest concentration of blood metabolites was observed in the first postpartum weeks. The SP100 and SP150 cows showed faster follicular growth and, consequently, a higher percentage of females with ovulatory follicles at 21 days postpartum than did NP cows (45.68, 41.11, and 11.00%, respectively). The SP150 cows had a higher pregnancy rate (40.74%), total calf production (295.88 kg/cow), and consequently, offspring sale value. An increased nutritional level in the third trimester of pregnancy improves the postpartum metabolic condition and productive efficiency of beef cows kept on NP.
一般来说，小牛肉生产发生在集约化程度较低的系统中。在肉牛妊娠阶段限制营养可能会对雌性动物随后的生产力产生负面影响。因此，本研究旨在评估妊娠第三个月的营养水平对在天然牧场（NP）中饲养的肉牛生产性能的影响。使用了 83 头夏洛莱牛×尼洛牛，年龄在 4 至 12 岁之间，根据妊娠第三个月的营养水平进行分组：NP，牛只补充 100%的能量和蛋白质需求（SP100）和牛只补充 150%的能量和蛋白质需求（SP150）。实验设计为完全随机，有三个处理和不同数量的重复。SP100 和 SP150 牛在分娩时（2.92 和 2.99 与 2.81 分）和繁殖季节开始时（2.90 和 2.95 与 2.80 分）的体况较好，而 NP 牛则不然。妊娠第三个月牛的营养水平不影响血液代谢物浓度。血浆白蛋白和总蛋白水平分别为 3.11 和 8.18g/dl。血糖和胆固醇分别为 74.96 和 166.50mg/dl。产后第一周血液代谢物浓度最低。SP100 和 SP150 牛的卵泡生长更快，因此产后 21 天有排卵卵泡的母牛比例更高（分别为 45.68%、41.11%和 11.00%）。SP150 牛的妊娠率（40.74%）、总产犊数（295.88kg/牛）和后代销售价值更高。妊娠第三个月增加营养水平可改善 NP 饲养的肉牛产后代谢状况和生产效率。
