中文摘要：

【目的】研究冷季补饲对白牦牛生产性能及草地生产力的影响,旨在为缓解冷季白牦牛掉膘现象以及减少白牦牛冬春季草场放牧压力提供参考。【方法】选取24头8月龄牦牛犊牛,分为4组,3组为补饲试验组,燕麦籽粒补饲量分别为0.1,0.2,0.3kg/（d·头）,另1组为对照;同时选取72头5-7岁成年牦牛,分为4组,其中3组为试验组,青贮玉米秸秆补饲量分别为1,2,3kg/（d·头）,另1组为对照,所有试验组采用白天放牧＋早晨补饲,对照组只进行放牧;在补饲同时,随机选取补饲组成年牛18头,对照组成年牛18头进行放牧试验,研究冷季补饲放牧对草地植被群落及开花、结实的影响。【结果】成年牦牛青贮玉米秸秆饲喂量为2kg/（d·头）时,冬季掉膘与对照有显著差异（P〈0.05）;犊牛燕麦籽粒饲喂量为0.3kg/（d·头）时,冷季增加体质量与对照差异达到显著水平（P〈0.05）;补饲与放牧结合区草地的植被盖度、高度、植物种数以及地上生物量总体优于纯放牧区,植被开花、结实株数总体高于纯放牧区;白牦牛成年牛在青贮玉米秸秆补饲饲喂量为2kg/（d·头）时,经济效益最高,可达99.6元/头。【结论】牦牛成年牛青贮玉米秸秆最佳补饲量为2kg/（d·头）,不建议犊牛使用燕麦籽粒进行冷季补饲;补饲与放牧结合可以改善高寒牧区草地状况。

英文摘要：

【Objective】Effects of feeding supplements in cold season on production performance of white yak and grassland productivity in alpine pastoral land were studied to provide reference for relief of body weight loss in winter and mitigation of grazing pressure in pastoral land.【Method】A total of 24 calves with the age of 8months were divided into four groups,involving three experimental groups feeding oat of 0.1,0.2,and 0.3kg/（d·head）was and one control group.At the same time,a total of 72 adult yaks with the ages of 5to 7years were divided into four groups,involving three experimental groups with silage corn stalk feeding amounts of 1,2,and 3kg/（d·head）and one control group.The yaks in experiment groups and control groups were grazed on natural grassland during daytime,but only those in experiment groups were supplemented in the morning.Meanwhile,18 adult yaks in experimental groups and 18 in con-trol groups were randomly selected for grazing experiment to study the effects of cold season feeding supplements on flowering and fruiting of plant communities.【Result】There was significant difference in body weight loss between the control group and the experiment group fed with 2kg/（d·head）silage（P〈0.05）.There was significant difference in weight gain between the control group and calves fed with 0.3kg/（d·head）oat（P〈0.05）.The plant coverage,height,species,and biomass on the grassland with combination of feeding and grazing were better than those of the grassland with only grazing,and the flowering and seeding rate had same trend.The maximum economic benefit of 99.6yuan/head for adult cattle was obtained when the supplement was 2kg/（d·head）.【Conclusion】The best intake for adult cattle was 2kg/（d·head）.Feeding yak calves with oats in winter was not suggested and combination of feeding and grazing could improve grassland in alpine pastoral areas.