低蛋白日粮对中国荷斯坦奶牛泌乳性能与饲养成本的影响OA

To investigate the effects of low-protein diets on lactation performance,milk quality,feed conversion efficiency,and feeding costs in Chinese Holstein dairy cows,this trial selected 60 healthy,lacta-ting Holstein cows in their second parity from the same farm,with an average body weight ranging from(659.21±4.88)kg to(678.33±4.88)kg.The cows were randomly and evenly divided into a control group and an experimental group,which were fed a traditional high-protein total mixed ration and an optimized low-protein total mixed ration,respectively.The results showed no significant differences(P＞0.05)between the two groups in terms of daily milk yield,daily feed intake,or feed conversion efficiency.Similar-ly,no significant differences(P＞0.05)were observed in milk fat percentage,milk protein percentage,fat-to-protein ratio,or milk yield loss.However,the somatic cell count and urea nitrogen concentration in milk were significantly higher in the control group compared to the experimental group(P≤0.05).Compared to the control group,the daily feed cost per cow in the experimental group was significantly reduced by RMB 5.98,and the feed cost per kilogram of milk decreased by 9.90％(P≤0.05).In conclusion,the use of an op-timized low-protein total mixed ration had no significant impact on milk yield or milk quality in Holstein dairy cows but significantly reduced feeding costs.