中文摘要：

为了发现有助于提高奶牛产奶量和乳房健康的关键乳房性状，为奶牛选种和管理提出建议，研究测定河北省定州某奶牛场一胎泌乳牛的乳头长度（859头牛的平均长度与均匀度）、乳房质地和乳房深度（1630头），应用最小二乘法原理，配合线性固定效应模型，分析了乳头长度、乳房深度和乳房质地对产奶量和体细胞数的影响。结果表明：在头胎牛中，乳头长度对产奶量有极显著影响（P〈0．01），对体细胞评分有显著影响（P〈0．05），乳头越长、均匀度越高的个体，其产奶量越高，体细胞数越低；同时，乳房质地对产奶量有极显著影响（P〈0．01），乳房较充盈硬实的个体产奶量较高；乳房深度和乳房质地对体细胞评分的影响虽然没有达到显著水平，但有乳房越深、质地越硬体细胞数越高的趋势。说明在生产中关注奶牛乳房性状，加强对乳房性状的选择与管理对于提高奶牛产奶性能、提高经济效益有着重要的作用。

英文摘要：

In order to find the key characters, that can be used to improve the milk yield and udder health, and provide suggestions to selection and management in dairy. Teat length （the average length and uniformity of 859 first lactation Holstein cows） , udder texture and udder depth （ 1 630 first lactation Holstein cows） were measured in a dairy cow farm in Dingzhou, Heibei province. The effects of the milk yield and somatic cell count （SCC） were analyzed by the least square method via the linear fixed effect model. The results indicated that, the teats length dis- played highly significant effect on milk yield （P 〈 0.01 ）, and significant effect on somatic cell score （SCS） （P 〈 0.05 ） in the first lactation cows. Cows with longer and more uniformed teats, produced more milk with lower SCC. Meanwhile, the udder texture displayed significant effect on milk yield （ P 〈 0.01 ） , and cows with tougher udder produced much more milk. In terms of SCS, though the effect of udder depth and udder texture were not significant, however, the tendency displayed that SCS increased with the increasing of the udder depth and texture score. It was concluded that udder characters played an important role in dairy production, and management and selection of udder characters were es- sential for the improvement of milk performance and economic benefits in dairy farming.