奶牛生产寿命和产奶量的相关性研究

Study of Association Between Production Life of Dairy Cattle and Its Milk Yield

本研究利用陕西省西安市现代农业开发区第二奶牛场1990年～2002年间249头已淘汰奶牛的胎次及产奶量记录等资料,对奶牛的生产寿命即第一胎次至淘汰的泌乳天数和生产效益的关系进行了研究。结果表明,奶牛的生产寿命与终生产奶量之间存在强正相关,相关系数为0．99。奶牛的使用年限和产奶量之间存在显著的曲线相关(P＜0．05)。此外,研究结果表明,该奶牛场奶牛不同胎次产奶量以第5胎次为最高。

Total 249 records of culled Holstein cows from 1990 to 2002 in 2nd dairy farm of Xi＇an modern agriculture industrial zone were collected to analyze the relationship between the production life of cow -lactation days and production benefits in this paper. The results showed that there was a strong positive correlation between production life and whole life milk yield of cow and the coefficiency of association was 0. 99. There was a significant curve association between production life and milk yield of experimental cows （P〈0. 05）, The results also indicated that these cows got a highest milk amount in their 5th lactation comparative to other milking time.