Zhou Qijun, Geng Zijian, Lian Shuai, Wang Jianfa, Wu Rui
College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinfeng Road, Daqing 163319, China.
China Key Laboratory of Bovine Disease Control in Northeast China, Ministry of Agriculture and Rural Affairs, Daqing 163319, China.
Animals (Basel). 2025 Aug 25;15(17):2495. doi: 10.3390/ani15172495.
The DHI data is crucial for monitoring the udder health of dairy cows during the breeding process. This study aimed to investigate the factors influencing milk production in dairy cows throughout this period. We analyzed DHI data from Holstein dairy cows in the Heilongjiang region, alongside the incidence of mastitis. The findings revealed that high-yielding cows demonstrated significantly higher peak milk yield days, peak milk yield, urea nitrogen levels, 305-day milk yield, and persistency ( < 0.0001) compared to their low-yielding counterparts. Conversely, high-yielding cows exhibited lower protein rates, fat-to-protein ratios, and milk fat rates ( < 0.0001). Additionally, the somatic cell count (SCC) in high-yielding cows was significantly lower than that in low-yielding cows ( < 0.0001). The multivariate linear regression analysis of the DHI data indicated that parity was the primary determinant affecting both milk yield and SCC. Statistical analysis of cows with clinical mastitis revealed that those experiencing a single episode of clinical mastitis during the lactation period were predominantly in their first and second parities, while recurrent cases were primarily observed in the second and third parities. These results suggest that as the number of lactations increases, the SCC also rises, reflecting the cumulative impact of parity on the udder health of dairy cows.
奶牛生产性能测定（DHI）数据对于监测奶牛繁殖过程中的乳房健康至关重要。本研究旨在调查这一时期影响奶牛产奶量的因素。我们分析了黑龙江地区荷斯坦奶牛的DHI数据以及乳腺炎发病率。研究结果显示，与低产奶牛相比，高产奶牛的产奶高峰天数、产奶高峰量、尿素氮水平、305天产奶量和泌乳持续力显著更高（<0.0001）。相反，高产奶牛的蛋白率、脂肪与蛋白比和乳脂率较低（<0.0001）。此外，高产奶牛的体细胞计数（SCC）显著低于低产奶牛（<0.0001）。对DHI数据的多元线性回归分析表明，胎次是影响产奶量和SCC的主要决定因素。对临床型乳腺炎奶牛的统计分析显示，泌乳期经历单次临床型乳腺炎的奶牛主要处于第一和第二胎次，而复发病例主要出现在第二和第三胎次。这些结果表明，随着泌乳次数的增加，SCC也会升高，这反映了胎次对奶牛乳房健康的累积影响。
