荒漠草原山羊和绵羊冬春季牧食行为及对草地的影响

Grazing behaviors of goats and sheep in winter and spring and their effects on the desert steppe of Inner Mongolia

于2008年1月至3月,在内蒙古短花针茅荒漠草原典型地段,设计了4个不同比例结构牧群(山羊与绵羊的数量比分别为1:0、1:1、1:3和0:1),将白天放牧时间分为出牧、定牧和归牧3时段,并采用全日制跟群放牧观察法观测各牧群中山羊与绵羊牧食行为活动节律和采食行为指标动态,主要包括采食速度、采食时间、采食时行进步数、采食口数、单口采食量和日采食量,同时对羊只体重变化进行了测定。结果表明:冬、春季放牧山羊与绵羊白天活动节律均表现为采食>游走>打斗,其中采食总时间占全天放牧时间的70%以上。冬、春季采食时间与游走时间之比在初牧时段无差异,而在定牧和归牧时段差异显著,且该比值在春季均高于冬季;不同放牧季节对羊只的采食行为指标均产生显著的影响。春季与冬季相比,山羊和绵羊单口采食量和日采食量均降低,而全天采食口数和采食时行进步数均增加。单一结构牧群中,山羊冬、春季对草地的影响(主要包括采食和践踏作用)均大于绵羊。混合牧群结构中,山羊冬季放牧对草地影响大于绵羊,春季则相反。相对而言,1:1结构牧群中羊只对草地影响最小,掉膘程度最轻,结构比较合理。

The dynamics of grazing behavior,ingesting behavior indexes and weight of grazing goats and sheep were measured in the flocks with four different proportions of livestock in winter and spring in the Stipa breviflora desert steppe from January to March,2008.Ingesting behavior indexes including ingesting speed,ingesting time,walking steps when ingesting,total bites of daylight ingesting,intake per bite and daily intake（DM）.The ratios of goats to sheep in the flocks were 1：0,1：1,1：3 and 0：1 respectively.The main results showed that ingesting behavior took the longest time among the rhythm of grazing goats and sheep in winter and spring in daylight,wandering was secondary and fighting was the least.The ingesting time made up to over 70% of total grazing time.The ratio of foraging time to wandering in first grazing period had no significant difference between winter and spring,while there was significant difference between secondary grazing period and last grazing period,and the ratio in spring was higher than in winter.Different grazing seasons had a great impact on grazing behaviors.Comparing spring and winter,intake per bite and daily intake decreased.However,the total bites and walking steps of whole day foraging all increased.In winter and spring,goats in the flock of 1：0 affected the desert steppe greater than sheep in the that of 0：1.In the 1：1 and 1：3 flocks,goats affected the steppe heavier than sheep in winter,and it was opposite in spring.Goats and sheep in the flock of 1：1 gave the least effects on steppe.The weight lost in this flock was less than in the others.So the ratio of goats to sheep in flock of 1：1 was considered reasonable and practicable.