放牧强度对山羊采食行为的影响

南方地区水热条件好,草地资源丰富且放牧家畜种类和数量较多,为充分利用当地草地资源,促进草畜平衡,本试验研究了我国西南地区人工草地不同牧压下山羊放牧行为的变化。试验采用野外群体观察法对2种牧压(重牧H和轻牧L)下山羊放牧行为及其参数进行观测记录。结果表明,2种牧压下放牧山羊采食时间都极显著(P<0.01)大于其他行为时间;鸭茅、黑麦草、白三叶的采食时间分别占总采食时间的29.2%,29.0%,25.4%,3种牧草的采食时间之和极显著(P<0.01)大于杂草的采食时间,但3种牧草之间无显著差异(P>0.05);随牧压增加与时间推移,山羊采食速度逐渐降低,但差异不显著(P>0.05);山羊采食速度与口食量呈现负相关的关系。本研究表明,放牧载畜量作为草地管理手段之一,可用来调控草地组成,增加家畜有效采食量,提高山羊放牧系统的经济效益与当地农民收入。

Effects of grazing intensities on foraging behaviors of goats on a cultivated pasture of southern China

There are fairly rich forage resources and species and quantity of grazing livestock with good climatic conditions in southern China. To promote the utilization of local pasture resources and the balance between forage and livestock, changes of foraging behaviors of goats under different grazing intensities were studied by field observation group methods on a cultivated pasture of southwestern China. Goats under the light and heavy-grazing regimes spent more time in eating than in other activities (P<0.01). Goats grazed in the pastures spent an average of 29.0%, 29.2%, 25.4% and 16.4% of their total eating time grazing four types of plants: ryegrass, cocksfoot, white clover and forbs respectively. Goats allocated much more of their eating time to the first three species than to the forbs (P<0.01) but there was no significant difference (P>0.05) in the grazing time of the three species. Biting rates of goats gradually decreased with an increase of grazing intensity and as the season progressed, but the differences were not significant (P>0.05). There was a negative relationship between bite rate and bite weight of goats. The stocking rates showed the potential to serve as a management tool for manipulating the pasture composition, enhancing goats’ effective intakes and thus improving the financial outputs of goat grazing systems and the incomes of local farmers.