Department of Animal Science, Faculty of Agriculture and Natural Resources, Arak University, Arak38156-8-8349, Iran.
Department of Animal Science, College of Agriculture Science and Engineering, University of Tehran, Karaj, Iran.
Br J Nutr. 2020 Jun 14;123(11):1247-1257. doi: 10.1017/S0007114520000586. Epub 2020 Feb 20.
The present study evaluated the interaction effects of n-3 fatty acids (from linseed oil (LSO), 0 v. 2·5, % DM basis) with rumen undegradable:degradable protein (RUP:RDP) ratios (low ratio (LR) 27:73; high ratio (HR) 38:62 based on crude protein %) in dairy calves' starter diet. Forty-eight 3-d-old female Holstein dairy calves (41·5 kg of body weight (BW)) were allocated in a 2 × 2 factorial arrangements in the following treatments (n 12 calves/each): (1) no supplementation of LSO with LR (NLSO-LR); (2) no supplementation of LSO with HR (NLSO-HR); (3) supplementation of LSO with LR (LSO-LR) and (4) supplementation of LSO with HR (LSO-HR). The calves were weaned on day 53 of the experiment and remained in the study until day 73. Intake was not affected by LSO and RUP:RDP ratio. However, average daily gain (ADG) was improved with LSO supplementation. Feeding the HR diet increased ADG compared with the LR diet during the entire period. Final BW was greater in calves fed on the LSO than those fed the NLSO diet. Microbial protein production did not differ among treatments. Calves fed on LSO diets had greater feed efficiency than those which were not fed on LSO diets. The calves supplemented with LSO had greater wither and hip heights compared with the unsupplemented calves. The glucose, cholesterol, HDL and insulin concentrations increased in calves supplemented with LSO. In conclusion, the HR diet improved calves' performance post-weaning; however, LSO could enhance growth performance of dairy calves during the pre-weaning period.
本研究评估了 n-3 脂肪酸（来自亚麻籽油（LSO），0 v. 2·5，％DM 基础）与瘤胃未降解：可降解蛋白（RUP：RDP）比值（低比值（LR）27:73；高比值（HR）38:62 基于粗蛋白%）在奶牛犊牛开食料中的互作效应。48 头 3 日龄雌性荷斯坦奶牛犊牛（41·5 kg 体重（BW））按照 2 × 2 因子安排分配到以下处理（n 12 头/每头）：（1）不补充 LSO 与 LR（NLSO-LR）；（2）不补充 LSO 与 HR（NLSO-HR）；（3）补充 LSO 与 LR（LSO-LR）和（4）补充 LSO 与 HR（LSO-HR）。犊牛在实验的第 53 天断奶，并在研究中一直持续到第 73 天。摄入不受 LSO 和 RUP：RDP 比值的影响。然而，添加 LSO 可提高平均日增重（ADG）。整个时期，高 RUP：RDP 比值的日粮增加 ADG 。饲喂 HR 日粮的犊牛最终体重大于饲喂 LR 日粮的犊牛。饲喂 LSO 日粮的犊牛比不饲喂 LSO 日粮的犊牛微生物蛋白产量更高。饲喂 LSO 日粮的犊牛的饲料效率大于不饲喂 LSO 日粮的犊牛。补充 LSO 的犊牛的肩高和臀高大于未补充 LSO 的犊牛。补充 LSO 的犊牛的血糖、胆固醇、HDL 和胰岛素浓度增加。总之，高 RUP：RDP 比值的日粮改善了犊牛断奶后的性能；然而，LSO 可以提高奶牛犊牛在断奶前的生长性能。
