中国荷斯坦牛部分乳房结构特性对泌乳性能的影响

Effects of Some Udder Traits on Lactating Performance of Holstein Cows

本研究对规模化场奶牛乳房结构部分性状进行评价和测定,旨在分析其影响因素及其与泌乳性能的关系。现场评价和测定我国北方6个规模化奶牛场荷斯坦牛的乳房均衡(2 030条)、乳头长度(1 551条)和乳头位置评分(分前、后乳头,2 839条),使用SAS 9.2 GLM过程采用固定效应模型分析影响上述3个乳房性状的因素,同时分析3个单项性状对校正日产奶量和体细胞评分的影响。结果表明:场和胎次对3个乳房性状影响极显著(P<0.01);前、后乳头位置和后乳头长度对校正日产奶量有显著影响(P<0.05),校正日产奶量与前乳头位置评分值呈正比,与后乳头位置评分值呈反比;前乳头位置和长度对体细胞评分有显著影响(P<0.05),体细胞评分随前乳头位置评分的增大而减小;5~5.5 cm的乳头长度对于校正日产奶量和体细胞评分都最佳。本研究结果为通过乳房性状选择、淘汰并提高奶牛的生产性能、乳房健康提供了参考。

This research evaluated and measured some udder traits of Holstein cows in scaled dairy farm to derive factors affecting udder traits and relationship between udder traits and milk yield performance. Udder balance （2 030 cows）, teat length （grouped into front and rear teats, 1 551 cows） and teat placement score （grouped into front and rear teats, 2839 cows） from 6 scaled Holstein dairy farm in Northern China were selected to analyze by GLM procedure of SAS 9.2 version with a fixed effect model, to find out factors which affect three traits and the effect of three traits on lactating performance of Holstein cows. Results show that farm and parity had very significant effects （P〈0.01） on three traits, front and rear teat placement and rear teat length had significant effects （P〈0.05） on herd test adjusted corrected milk （HTACM）; HTACM is in direct proportion to front teat placement score and inverse proportion to rear teat placement score; While length and placement of front teat had significant effects （P〈0.05） on somatic cell score （SCS）, SCS decreases with front teat placement score increased; 5-5.5 centimeters length for front teat was the optimal both in terms of HTACM and SCS performance. The results from current study provides reference to emphasize importance of udder traits in selection of Holstein cows, and to improve production performance and udder health through culling the ones with the inferior udder characteristics.