奶牛乳头长度及乳头末端状况的重要性初探

Preliminary Study on the Importance of Cow Teat-length and Teat-end Condition

为评估奶牛乳头长度和乳头末端健康状况在奶业生产中的重要性,本研究对山西省奶牛场的514头泌乳牛乳头长度和乳头末端状况进行评分,并收集了该场2013年6月24日的DHI数据。采用固定模型分析牛只泌乳阶段、胎次、乳头长度和乳头末端状况四个因子对产奶量和体细胞数(SCC)的影响。经抽样分析发现,该牛场泌乳牛群乳头长度集中在4~6cm。乳头长度短于4cm的个体有22头(6.6%),最长乳头超过6cm的个体有53头(15.8%)。与乳头长度为4~6cm的牛只相比,乳头长度超过6cm或短于4cm的奶牛,其乳头末端健康状况显著下降(P【0.05)。该牛群乳头末端评分的均值为2.25分,参照文献评价乳头健康的标准,该场泌乳牛乳头健康状况良好。经对前后乳区的乳头末端损伤程度进行分析,表明奶牛后乳区乳头末端状况极显著好于前乳区(P【0.01)。乳头长度和乳头末端状况对产奶量和SCC的影响不显著(P】0.05),但乳头过长时奶牛平均SCC比正常个体高出5.8万个/mL。乳头有损伤的个体较乳头健康奶牛SCC的均值高出2.2万个/mL。评价牛群的乳头长度和乳头末端状况有助于了解牛群的乳房健康状况,可为牛群管理提供有用建议。

To assess the importance of teat length and teat-ends condition in dairy production, we scored teat-length and teat-ends condition of 514 lactating cows in a Holstein dairy farm in Shanxi. DHI data measured on June 24 th, 2013 was also collected. A fixed model was employed to analyze the impact of four factors(lactation stage, parity, teat-length and teat-end condition) on milk yield and somatic cell count. A random sample analysis of teat length indicated that the most of teat length were within a range of 4~6cm. The number of cows with teat shorter than 4cm was 22(6.6%), and 53(15.8%) cows had the longest teat over 6cm. There were significant differences(P <0.05) of health status between teat-end health status with different teat-lengths. Compared with the 4~6cm teat,teats longer than 6cm or shorter than 4cm have a significant increase in the probability of teat injury. The mean score of the teatend condition of this population was 2.25.The average teat-end health status indicated that the teat-end of the whole dairy farm was in good health condition, based on the published standards of scoring teat-end health condition. The teat-end condition showed significant difference(P<0.01) between the rear teats and front teats, and front teats were much more health than rear teats. The effect of the teat length and teat-end condition were not significant on the milk yield and SCC(P>0.05). The average SCC of milking cow with longer teat were 58 000/mL higher than that of normal individuals. The mean SCC of individual with injured teats were 22 000/mL higher than that of individuals with healthy teats. Evaluating the teat length and teat-end condition helps finding out the health status of the dairy herd and provides useful suggestions for dairy herd management.