Chaltasian Agri-Animal Production Co., Varamin, Tehran, Iran.
Department of Eco-Friendly Livestock Science, Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang, Gangwon-do, Korea.
Vet Med Sci. 2023 May;9(3):1338-1348. doi: 10.1002/vms3.1088. Epub 2023 Feb 1.
The interaction effects of duration of stay in fresh-cow diet and supplementation with rumen-protected glucose (RPG) on productivity of dairy cows are largely unknown. We hypothesised that a faster transition from fresh-cow diet (higher forage:concentrate) to lactation-cow diet (lower forage:concentrate), combined with supplementation of fresh-cow diet with RPG will have positive effects on production and health of dairy cows.
To investigate the immediate and long-term effects of length of stay in fresh-cow diet and supplementation with RPG on productive and reproductive performance of high-producing dairy cows.
A total of 264 multiparous Holstein cows (average parity ± standard deviation = 3.2 ± 1.3, ranging from 2 to 6) were used in a 2 × 2 factorially arranged trial. Treatments were the feeding duration of a fresh-cow diet for 14 or 21 days, each combined by daily supplementation of the fresh-cow diet with ground corn grain or RPG product top dressed at 500 g/day/head.
The earlier transition from fresh-cow to lactation diet resulted in greater milk production from 15 through 21 days in milk (DIM; by 2.28 kg/day), and also fat-corrected milk production on 30 and 60 DIM, respectively. Corn grain or RPG supplementation did not affect the average milk production (1 to 21 DIM), as well as milk production and composition on 30 and 60 DIM. Although extent of body condition loss at transition tended to be lesser in cows switching faster to lactation diet, these cows lost more body condition from 30 to 90 DIM. Survival analysis on calving-to-conception interval and time to removal from herd did not find any significant difference across treatments.
The positive effects of earlier transition from fresh-cow to lactation diet were evident by greater milk production from 15 through 21 DIM, and fat-corrected milk production (30 and 60 DIM), at the expense of body condition in high-producing dairy cows. A daily topdress of RPG on fresh-cow diet had no immediate or carryover effects on production of dairy cows.
停留时间在新鲜奶牛日粮和补充瘤胃保护葡萄糖（RPG）对奶牛生产性能的互作效应在很大程度上是未知的。我们假设，从新鲜奶牛日粮（更高的粗饲料：浓缩物）向泌乳奶牛日粮（更低的粗饲料：浓缩物）的更快过渡，结合新鲜奶牛日粮中 RPG 的补充，将对奶牛的生产和健康产生积极影响。
研究停留时间在新鲜奶牛日粮和补充 RPG 对高产奶牛生产性能和繁殖性能的即时和长期影响。
总共使用了 264 头荷斯坦奶牛（平均胎次 ± 标准差=3.2±1.3，范围 2 至 6）进行 2×2 因子试验。处理为新鲜奶牛日粮的喂养时间为 14 或 21 天，每个处理均结合新鲜奶牛日粮每日补充地面玉米谷物或 RPG 产品，顶部涂抹 500g/天/头。
从新鲜奶牛到泌乳奶牛日粮的更早过渡导致在 15 至 21 天泌乳期间的产奶量（DIM）增加 2.28kg/天，以及在 30 和 60 DIM 的脂肪校正奶产量分别增加。玉米谷物或 RPG 补充剂对平均产奶量（1 至 21 DIM）以及 30 和 60 DIM 的产奶量和组成没有影响。尽管在更快过渡到泌乳日粮的奶牛中，体况损失的程度趋于较小，但这些奶牛从 30 到 90 DIM 损失了更多的体况。在产犊至受孕间隔和从畜群中移除的时间的生存分析中，处理之间没有发现任何显著差异。
从新鲜奶牛到泌乳奶牛日粮的更早过渡的积极影响体现在 15 至 21 DIM 的产奶量增加，以及脂肪校正奶产量（30 和 60 DIM）增加，而高产奶牛的体况则受到影响。在新鲜奶牛日粮中每天顶部涂抹 RPG 对奶牛的生产没有即时或后续影响。
