目的:牦牛作为青藏高原的主要畜种之一,但每年却要面对严冬和长达7.5个月的枯草期,期间一直处于半饥饿状态,掉膘严重,有的甚至因饥饿而死亡。通过对中甸牦牛体重监测,揭示掉膘的程度,为冷季补饲和短期育肥提供理论依据。方法:对一年中不同时间点的中甸牦牛体重监测,比较分析不同季节的掉膘情况。结果:调查发现,11月份中甸牦牛膘力最好,5月份体重最轻,成年公牛(含阉牛)体重分别为315.8±59.1 kg和209.5±66.3 kg,母牛体重分别为210.5±33.8 kg和148.7±20.2 kg,相对体重掉膘分别为33.7%和29.4%。在一般营养水平下,圈养1～4岁中甸牦牛(7-11月),公母牛体重分别可到207 kg和187 kg;体重大的个体采食能力更强,增重更快,母牛体重已达到成年体重,架子还不到成年状态,圈养期的平均日增重为600 g,每头牛可盈利近1 000元,效益较好。结论:必须做好饲草料种植和储备,以应对冬春季节严重掉膘的情况;中甸牦牛短期圈养育肥可获得较好的经济效益,值得持续试验示范。

Objective: Yak, is one of the main livestock species in Qinghai-Tibet Plateau, but it must face the severest winter and 7.5 months of dry grass period annually. During the period, yak has undergone in a semistarvation state, weight loss seriously, and some even died of starvation. By monitoring the body weight of Zhongdian yak, the weight loss was revealed in the different seasons, to provide theoretical basis for supplementary feeding and short-term finishing in cold season. Methods: The body weight at the different time points in a year was monitored to compare the extent of weight loss in Zhongdian yak. Results: Based on the investigation, Zhongdian yak had the best physical state in November while the lightest body weight happened in May. The body weights of adult bulls(including the castrated) were 315.8 ± 59.1 kg in November and209.5 ± 66.3 kg in May, as the cows' body weights were 210.5 ± 33.8 kg and 148.7 ± 20.2 kg, of which the relative weight losses were 33.7% and 29.4%, respectively. Under the common nutritional level, the body weights of 1～4 year-old in Zhongdian yak(July to November) reached 207 kg and 187 kg for bulls and cows,respectively. The individuals with heavier body had stronger intake ability, of which the weight gains was higher that the body weight of cows reached adult weight, but the stature was not mature yet. The average daily gain of Zhongdian yak in captivity was 600 g, and each might make a profit of nearly 1 000 Yuan with a proper benefit. Conclusion: It should promote the forage planting and storage to meet weight loss seriously in winter-spring seasons. And the short-term fattening could obtain better economic benefits, worthy of continuous experiment and promotion in Zhongdian yak.