Abstract: The purpose of this study was to investigate the factors affecting somatic cell counts (SCC) and milk composition of Chinese Holstein cows in Ningxia. The correlation of 198 855 measurements of the dairy herd improvement (DHI) data of 19 020 Chinese Holstein dairy cows (from 2009 to 2018) from 7 different dairy farms was analyzed using Minitab software. The results showed that 1) SCC was significantly correlated with farm, year and parity (P < 0.05); 2) SCC fluctuated with season and calving month, and decreased first and then increased with increasing lactation length; and 3) there were significant correlations between SCC and milk yield, milk fat percentage, milk protein percentage, milk sugar percentage and dry matter percentage (P < 0.05). Moreover, SSC, milk yield and the major milk components were influenced by environmental factors (farm, year and season) and cow’s own factors (parity, calving season and lactation period). In summary, fine management is an effective avenue to improve milk production and quality.

Key words: Chinese Holstein cows; somatic cell count; milk composition; correlation analysis

摘要： 对宁夏奶源主产区荷斯坦牛乳体细胞数（somatic cell count，SCC）及牛乳中主要营养成分的影响因素进 行探讨。利用Minitab软件对宁夏地区2009—2018年间7 个牛场中19 020 头中国荷斯坦牛198 855 次奶牛生产性能测 定（dairy herd improvement，DHI）记录进行相关性分析。结果表明：奶牛场、年份、胎次与SCC具有显著相关性 （P＜0.05），SCC随季节、产犊月份变化而波动，SCC随泌乳期变化的趋势为先降低后升高；产奶量、乳脂、乳 蛋白、乳糖、乳中干物质含量与SCC具有显著相关性（P＜0.05），同时受到环境因素（奶牛场、年份、季节）及 奶牛自身因素（胎次、产犊月份、泌乳期）的影响。表明SCC、产奶量和乳中主要成分均会受到环境因素及奶牛自 身因素的影响，精细化管理是提高原料乳质与量的有效途径。

关键词: 中国荷斯坦牛；体细胞数；乳成分；相关性分析