da Silva Aline Gomes, Paulino Mário Fonseca, Detmann Edenio, Fernandes Henrique Jorge, da Silva Amorim Lincoln, Ortega Román Enrique Maza, de Carvalho Victor Valério, da Costa Lima Josilaine Aparecida, de Moura Felipe Henrique, Monteiro Mariana Benevides, Bitencourt Jéssika Almeida
Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-000 Brazil.
Present Address: Universidade Federal de Mato Grosso do Sul, Campo Grande, Mato Grosso, do Sul 79074-460 Brazil.
J Anim Sci Biotechnol. 2017 Oct 1;8:78. doi: 10.1186/s40104-017-0209-x. eCollection 2017.
Nutrition is one of the most important factors that affect animal performance, and it therefore also impacts on financial results in beef systems. In this way, finding the best strategy for feeding supplements is of paramount importance. Aiming to evaluate the effect of supplement feeding strategies for beef cows in the last third of gestation, two experiments were conducted. In Experiment 1, 35 pregnant Nellore cows were assigned to a completely randomized design with four treatments: control, which received no supplement; supplementation for the last 30 d of gestation (30-d; 3.0 kg/d); supplementation for the last 60 d of gestation (60-d; 1.5 kg/d); or supplementation for the last 90 d of gestation (90-d; 1.0 kg/d). All supplemented treatments received the same total amount of supplement throughout the experiment: 90 kg (20% of crude protein). A second experiment (Experiment 2) was delineated to evaluate the effects of the amounts offered in Experiment 1 on intake and metabolism. Four multiparous pregnant Nellore cows were assigned to a 4 × 4 Latin square design, with periods of 15 d each.
There was a linear effect of the number of days of supplementation on calving body weight (BW; < 0.05) and a quadratic effect on BW change from parturition to d 31 post-calving ( < 0.05), with cows on the 60-d strategy losing less BW post-calving. No difference was found in offspring birth BW ( > 0.10). A significant linear effect on interval from parturition to conception ( < 0.05) was observed, with the highest calving to conception interval being observed in the 90-d strategy. The level of supplementation did not affect forage intake or neutral detergent fiber digestibility ( > 0.10). Nitrogen excreted through urine tended to increase linearly with the level of supplementation ( < 0.10).
Providing 1.5 kg of supplement during the last 60 d of gestation improves cow performance after calving, reducing the magnitude of BW lost, and reduces the number of days from calving to re-conception in the following breeding season compared to the usually recommended period of supplementation of 90 d pre-partum.
营养是影响动物生产性能的最重要因素之一，因此也会影响肉牛养殖系统的经济效益。因此，找到最佳的补饲策略至关重要。为了评估妊娠后期三分之一阶段肉牛补饲策略的效果，进行了两项试验。在试验1中，35头怀孕的内洛尔母牛被分配到完全随机设计的四种处理中：对照组，不进行补饲；在妊娠最后30天进行补饲（30天组；3.0千克/天）；在妊娠最后60天进行补饲（60天组；1.5千克/天）；或在妊娠最后90天进行补饲（90天组；1.0千克/天）。在整个试验过程中，所有补饲处理组接受的补饲总量相同：90千克（粗蛋白含量为20%）。第二项试验（试验2）旨在评估试验1中提供的补饲量对采食量和代谢的影响。四头经产怀孕的内洛尔母牛被分配到4×4拉丁方设计中，每个阶段为期15天。
补饲天数对产犊体重（BW；P<0.05）有线性影响，对产后第31天的体重变化有二次效应（P<0.05），采用60天补饲策略的母牛产后体重损失较少。后代出生体重没有差异（P>0.10）。观察到从分娩到受孕间隔有显著的线性效应（P<0.05），90天补饲策略的产犊到受孕间隔最长。补饲水平对采食量或中性洗涤纤维消化率没有影响（P>0.10）。通过尿液排出的氮量倾向于随补饲水平呈线性增加（P<0.10）。
与通常建议的产前90天补饲期相比，在妊娠最后60天提供1.5千克补饲可提高母牛产后性能，减少体重损失幅度，并减少下一繁殖季节从产犊到再次受孕的天数。
