【摘要】 为进一步明确奶牛生产性能测定(DHI)在规模化奶牛场养殖管理中的作用，对陕西关中地区A、B、C 3个奶牛场2020年12月至2021年11月的DHI数据进行整理统计，分析季节、胎次、泌乳天数以及体细胞数(SCC)等不同因素对奶牛日产奶量和乳成分的影响。统计分析数据表明，冬季的乳脂率与乳蛋白率显著高于春季和夏季；第2～5胎次时奶牛有较高的日产奶量、高峰奶量和305 d奶量；泌乳天数在50～100 d时奶牛的日产奶量最大，泌乳天数大于100 d后，日产奶量逐渐下降；当SCC增加时，奶牛日产奶量、持续力以及305 d奶量逐渐降低，乳脂率和乳蛋白率逐渐升高。相关性分析数据表明，不同季节日产奶量与乳脂率、乳蛋白率均呈显著正相关；不同胎次奶牛日产奶量与乳脂率、乳蛋白率、SCC及尿素氮相关性显著；泌乳天数在50～100 d时，日产奶量与乳脂率、尿素氮呈显著正相关，与乳蛋白率、SCC呈显著负相关，在100～150 d时，日产奶量与乳脂率、乳蛋白率呈显著负相关，与SCC、尿素氮呈显著正相关；不同SCC条件下，奶牛日产奶量与乳脂率、尿素氮含量均显著正相关，当SCC小于25万个/mL时，奶牛日产奶量与乳蛋白率呈显著正相关，当SCC大于25万个/mL时，奶牛日产奶量与乳蛋白率呈显著负相关。结果表明，在陕西关中地区规模化奶牛场饲养管理过程中，应综合考虑季节、胎次、泌乳天数及SCC等因素的影响，因时因地优化饲养管理方案，从而提高奶牛泌乳性能和牛乳品质。更多还原

【Abstract】 In order to further understand the role of Dairy Herd Improvement(DHI) in large-scale development of the dairy farming industry, the DHI data of dairy farms A,B and C in Guanzhong, Shaanxi province from December 2020 to November 2021 were sorted out and analyzed the effects of different factors(seasons, parities, lactation days, and somatic cell count(SCC)) on the daily milk yield and milk composition of cows.Statistical analysis results showed that the milk fat percentage and milk protein percentage of dairy cows were significantly higher in the winter than in spring and summer.Daily milk yield, peak milk yield, and 305 d milk yield were higher in 2-5 parities than in others.Daily milk yield was greatest when cows were in lactation for 50-100 d and gradually decreased after more than 100 d.As the SCC increased, the daily milk yield, sustainability, and 305 d milk yield gradually decreased, whereas the milk fat and milk protein rates gradually increased.Correlation analysis results showed that there were extremely significant positive correlation in the daily milk yield with milk fat percentage and milk protein percentage of dairy cows in different seasons.The milk protein rate, SCC and urea nitrogen were significantly correlated with daily milk yield at different parities.Daily milk yield was positively correlated with milk fat percentage and urea nitrogen, but negatively correlated with milk protein percentage and SCC for 50-100 d of lactation.In lactation for 100-150 d, daily milk yield was significantly negatively correlated with milk fat percentage and milk protein percentage, but significantly positively correlated with SCC and urea nitrogen.The daily milk yield was positively correlated with milk fat percentage and urea nitrogen content under different SCC conditions.There was a significant positive correlation between daily milk yield and milk protein percentage when the SCC was less than 250 000/mL,but the result was opposite when the SCC was more than 250 000/mL.The above results indicated that it is necessary to comprehensively consider the season, parities, lactation days, and SCC in the process of feeding and management of large-scale dairy farms in Guanzhong, Shaanxi province, applying proper feeding management in line with the season and local conditions in the feeding of dairy cows to improve lactation performance and milk quality.更多还原