Factors affecting body tissue mobilization in early lactation dairy cows .1. Effect of dietary protein on mobilization of body fat and protein
Factors affecting body tissue mobilization in early lactation dairy cows .1. Effect of dietary protein on mobilization of body fat and protein
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DOI：
10.3168/jds.s0022-0302(97)76016-8
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发表时间：
1997-05-01
影响因子：
3.5
通讯作者：
Erdman, RA
中科院分区：
文献类型：
--
作者：
Komaragiri, MVS;Erdman, RA
选取20头荷斯坦奶牛，分别饲喂含16%和19%粗蛋白质（CP）和6%和9%瘤胃不可降解蛋白质（RUP）（干物质基础）的饲粮，研究增加RUP对组织动员和生产参数的影响。在产后第2、5和12周，使用D2O稀释技术测量奶牛的体成分，在产后第2周至产后第5周期间，身体组织损失最大，在此期间，饲喂两种处理的奶牛平均消耗54 kg体脂肪和21 kg体蛋白质。到产后第12周，奶牛继续动员18公斤的体脂，但体内蛋白质的量没有变化。身体状况评分变化的一个单位相当于大约40公斤的空体脂肪。空体能量在空体脂肪和蛋白质之间的分配表明，每单位的身体能量变化中，93%作为身体脂肪损失或增加，而身体蛋白质仅占7%。在饮食中增加RUP对产后空体蛋白、空体脂肪或空体能量的量没有影响。16%粗蛋白质组产奶量为39.8 kg， 19%粗蛋白质组产奶量为42.4 kg。饲粮中粗蛋白质含量为19%的奶牛产后前6周的干物质采食量和产奶量均低于饲粮中粗蛋白质含量为16%的奶牛。19%粗蛋白质饲粮的乳CP率更高（3.08%比2.89%），乳CP产量更高（1.29比1.15 kg/d）。
Twenty Holstein cows were fed diets that were formulated with 16 or 19% crude protein (CP) that contained, respectively, 6 and 9% ruminally undegradable protein (RUP) (dry matter basis) to study the effect of increased RUP on tissue mobilization and production parameters. Cows were enrolled in the study from -14 to 114 d postpartum Body composition measurements using the D2O dilution technique were made at -2, 5, and 12 wk postpartum Maximum loss of body tissue occurred between wk 2 prepartum and wk 5 postpartum during which time cows fed both treatments mobilized a mean of 54 kg of body fat and 21 kg of body protein. Cows continued to mobilize 18 kg of body fat through wk 12 postpartum, but the amount of body protein was unchanged. One unit of change in body condition score corresponded to about 40 kg of empty body fat. Partitioning of empty body energy between empty body fat and protein indicated that, for each unit of change in body energy, 93% was lost or gained as body fat, and body protein accounted for only 7%. Increasing RUP in the diet had no effect on the postpartum amounts of empty body protein, empty body fat, or empty body energy. Milk production was 39.8 kg for cows fed the 16% CP diet and 42.4 kg for cows fed the 19% CP diet. There was an interaction of treatment by week postpartum Both dry matter intake and milk production were lower during the first 6 wk postpartum but were greater thereafter for cows fed the 19% CP diet than for cows fed the 16% CP diet. Milk CP percentage was higher (3.08% vs. 2.89%), and milk CP yield tended to be greater (1.29 vs. 1.15 kg/d), for cows fed the 19% CP diet.