Fresh cows experience negative protein balance and mobilize body proteinto meet lactational demands. Reducing mobilization by increasingmetabolizable protein (MP) supply or improving the AA profile may improvemilk production later into lactation. Our objective was to determinewhether increasing MP concentrations at the expense of either non-forageor forage NDF (fNDF), or improving the AA profile affected empty body(EB) crude protein (CP) through transition and into early lactation. In arandomized block design, 40 primigravid and 40 multigravid Holsteinswere blocked by calving date and fed a common, prefresh diet (11.5%CP). After calving to 25 d in milk (DIM), cows were fed 1 of 4 diets: 1)deficient in MP (DMP, 17% CP, 24% fNDF), 2) adequate in MP using highinclusion of lignosulfonate-treated soybean meal (AMP, 20% CP, 24%fNDF), 3) adequate in MP using a blend of RUP and rumen- protectedAA (Blend, 20% CP, 24% fNDF), or 4) a similar diet but substitutingforage NDF rather than non-forage NDF with the blend (Blend-fNDF,20% CP, 19% fNDF). Cows were fed a common diet (17% CP) from26 to 50 DIM. At 7 d before anticipated calving, and at 7, 25 and 50DIM, body composition was estimated using the urea dilution method.Mixed models with fixed effects of treatment, day (repeated), parity, theirinteractions, covariate effect of prepartum measurements and random effectsof block nested within parity were used to analyze data. Day bytreatment (P < 0.03) interactions were observed for EB CP. From 7 dbefore calving to 7 DIM, the loss of EB CP was similar (avg. 34 g/d), butfrom 7 to 25 DIM, cows fed AMP (139 g/d) and Blend-fNDF (147 g/d)lost more EB CP compared with Blend (8 g/d). After treatments ended(>25 DIM), gains/losses of EB CP were similar, and the average (2 g/d)was not different from zero (P > 0.15). Final EB CP was similar (avg.81.5 kg) at 50 DIM. Overall, feeding fresh cows a high MP diet froma blend of proteins and AA reduced the loss of EB CP, which may bewhy these cows had higher milk production during the carry-over period.
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机译：新奶牛体验阴性蛋白质平衡并发验身体蛋白质满足泌乳的需求。通过增加降低动员可代谢蛋白质（MP）供应或改善AA型材可以改善后来牛奶生产进入哺乳期。我们的目标是确定是否以非饲料为代价增加MP浓度或饲料NDF（FNDF），或改善影响空体的AA型材（EB）通过过渡和早期哺乳期粗蛋白（CP）。在一个随机块设计，40个Primigravid和40个多重rulaviD holsteins通过犊牛日期被封锁，并喂养常见的提力饮食（11.5％CP）。在牛奶中加入25 d后（暗淡），奶牛喂食4饮食：1）缺乏MP（DMP，17％CP，24％FNDF），2）使用高度适当包含木质素磺酸盐处理的大豆粕（AMP，20％CP，24％FNDF），3）使用RUP和Rumen保护的混合物充足的MPAA（混合，20％CP，24％FNDF）或4）类似的饮食，但取代Forage NDF而不是用混合物（Blend-FNDF）而不是非饲料NDF，20％CP，19％FNDF）。奶牛喂养常见的饮食（17％CP）26到50昏暗。在预期的犊牛之前，7,25和50暗淡，使用尿素稀释方法估计体组成。混合模型具有固定效果的治疗，日（重复），平价，其相互作用，预备测量和随机效应的协变量嵌套在奇偶校验中的块用于分析数据。一天对EB CP观察治疗（P <0.03）相互作用。从7 D.在削减到7次调光之前，EB CP的损失相似（AVG。34 G / D），但从7到25次，奶牛喂amp（139 g / d）和混合 - fndf（147 g / d）与混合物（8 G / D）相比，损失了更多的EB CP。治疗结束后（> 25次暗），EB CP的收益/损失相似，平均值（2 G / D）与零（p> 0.15）不同（p> 0.15）。最终的EB CP类似（AVG。81.5千克）在50℃下。总的来说，喂养新鲜奶牛的高级饮食蛋白质和AA的混合物减少了EB CP的损失，这可能是为什么在随身期间，这些奶牛在牛奶期间具有更高的牛奶生产。
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