天祝夏季草原放牧条件下牦牛产奶性能的研究

The analysis of milk performance of yaks in summer pasture in the Tianzhu County of Gansu Province

在天祝藏族自治县下南泥沟、岱乾上南台和乌鞘岭3个暖季牧场，对不同胎次牦牛的产奶量、乳脂肪、乳蛋白质含量及牧场草产量进行了研究．结果表明：3个牧场，1～5胎次母牦牛产奶量随胎次的增加而增高，5胎以后，母牦牛产奶量开始下降；下南泥沟牧场3～5胎母牦牛日均产奶量显著高于岱乾上南台和乌鞘岭牧场（P＜0．05）；下南泥沟7～8月份牦牛月产奶量（33．96kg）比岱乾上南台（28．07kg）和乌鞘岭（27．30kg）牧场分别高出21．8％和14．7％．3个牧场牦牛乳脂肪及蛋白质含量差异不显著．3牧场中，下南泥沟牧场可食牧草产量高于岱乾上南台牧场和乌鞘岭牧场，而其放牧强度却低于该两牧场．

The milk yield of yaks with different birth,the contents of fat.and protein of the yaks＇ milk, and forage yield in three alpine pasture in the Tianzhu County of Gansu province were measured. The results showed that the milk yield was increased with the increase of the birth of yaks. After fifth birth,the milk yield tended to decrease; the milk yield of yaks from third to fifth birth in the Xianannigou pasture was significantly higher than that of their counterpart in Daiqianshangnantai pasture and Wushaoling pasture（P〈0.05） ,and the mean milk yield of the former in July and August was higher than that of the two later;the pasture production in the Xianannigou was higher than that in the Daiqianshangnantai and Wushaoling. The higher milk performance of yaks in the Xianannigou was due to the higher pasture productivity and its low graving stress in the pasture.