Department of Animal Nutrition, University of Veterinary and Animal Sciences, Outfall Road, Lahore 54000, Pakistan.
Department of Livestock Production, University of Veterinary and Animal Sciences, Outfall Road, Lahore 54000, Pakistan.
J Dairy Sci. 2021 Sep;104(9):9886-9901. doi: 10.3168/jds.2021-20218. Epub 2021 Jul 1.
An experiment was conducted to determine the effects of low and high metabolizable protein (MP) diets when fed for ad libitum and controlled intake during the prepartum period on postpartum lactation performance and feeding behavior of dairy cows. Thirty-six multiparous Holstein cows were blocked by parity, expected calving date, and previous lactation milk yield at -21 d relative to expected calving and were randomly assigned to 1 of 4 close-up period dietary treatments providing low MP (LMP) or high MP (HMP) diets with controlled intake (CNI) or ad libitum intake (ALI). The concentrations of MP were 65 and 90 g/kg dry matter for LMP and HMP diets, respectively, whereas intake was controlled to supply 100 and 160% of the NRC (2001) energy requirements for CNI and ALI groups, respectively. The concentration of net energy for lactation (NE) in the treatment diets was 1.50 Mcal/kg. All cows were fed a similar lactation diet after calving (1.50 Mcal/kg of NE and 83.3 g/kg of MP). The HMP diet increased dry matter intake during the first 3 wk and tended to increase dry matter intake over the 9 wk of lactation. Meal size and eating rate increased in the ALI cows during the prepartum period. Meal frequency increased with the HMP diet during the postpartum period. Milk yield increased by 15.2% with the HMP diet over the 9 wk of lactation. The HMP diet increased energy-corrected milk (ECM) yield in CNI versus ALI cows, whereas the LMP diet increased ECM yield in ALI versus CNI cows over the 9 wk of lactation. The increase in ECM yield of LMP-ALI versus LMP-CNI cows was supported by greater body condition loss and serum β-hydroxybutyrate over the 9 wk of lactation. Taken together, these data indicate that prepartum controlled intake of a high protein diet can provide the benefits of both strategies.
进行了一项实验，以确定在产前期间自由采食和控制采食低代谢蛋白（MP）和高代谢蛋白（MP）饮食对奶牛产后泌乳性能和采食行为的影响。36 头经产荷斯坦奶牛按胎次、预计产犊日期和前泌乳期产奶量在预计产犊前-21 天分为 4 组，并随机分配到 4 种接近期日粮处理中的 1 种，提供低 MP（LMP）或高 MP（HMP）饮食，分别采用控制采食（CNI）或自由采食（ALI）。LMP 和 HMP 日粮的 MP 浓度分别为 65 和 90g/kg 干物质，而采食则分别控制在满足 CNI 和 ALI 组 NRC（2001）能量需求的 100%和 160%。处理日粮的泌乳净能（NE）浓度为 1.50Mcal/kg。所有奶牛产后均饲喂相似的泌乳日粮（泌乳净能 1.50Mcal/kg，MP 83.3g/kg）。HMP 日粮增加了产前三周的干物质采食量，并且在泌乳的 9 周内有增加干物质采食量的趋势。产前阶段 ALI 奶牛的采食时间和采食速度增加。产后阶段 HMP 日粮增加了采食频率。HMP 日粮在泌乳的 9 周内使产奶量增加了 15.2%。HMP 日粮增加了 CNI 奶牛的能量校正奶（ECM）产量，而 LMP 日粮在泌乳的 9 周内增加了 ALI 奶牛的 ECM 产量。LMP-ALI 奶牛的 ECM 产量增加得益于泌乳 9 周内更大的体况损失和血清β-羟丁酸。综上所述，这些数据表明，产前控制采食高蛋白日粮可以同时受益于这两种策略。
