放牧生态系统家畜牧食行为研究进展

Advances in Studies on Livestock Grazing Behaviour in Grassland Ecosystem

家畜牧食行为包括采食、反刍,游走,饮水,卧息和排泄粪尿,其中采食和反刍是两大主要行为。本文介绍了放牧家畜与牧草间的相互关系,放牧通过采食牧草,降低牧草光合叶面积指数而影响牧草生长发育。放牧作为一种人为干预,影响植被组成和群落结构,高放牧压力下,导致草地退化。在放牧情况下,牧草具有避牧和耐牧两种生存策略。由于放牧草地物种多样,家畜选择采食适口性高的植物或植物组成部分。介绍了国内外计算采食量的各种方法,包括计算放牧前后草地牧草生物量,通过内外源标记物计算排粪量或通过采食时间,单口采食率、单口采食量来计算采食量。家畜采食成分的测定一直以来都是难点,有直接观测法、瘤胃内容物或粪便镜检法、瘤胃瘘管法和炼烷烃技术等。

Grazing behaviour including behaviour of foraging, walking, ruminating, drinking, resting, excreting is mainly composed of foraging and ruminating behaviour. The interrelationship between grazing animals and forage was illuminated in this paper. Grazing may affect the growth and development of forage by decreasing leaf area index （LAI）. Grazing is an artificial disturbance, which affects sward composition and community structure. High stocking rate may result in grassland degradation. Under grazing conditions, forages have two kinds of surviving tactics： grazing avoidance and grazing tolerance. Grazing animals select forages or the part with high appetite because of the high multi-variate species in the sward. Many kinds of methods for calculating intake were introduced, including the magnitude of the difference between pre-and post-grazing herbage mass and the duration between the measurements, through internal or external markers to calculate faecal output or through grazing time, bite rate and bite mass to calculate intake. Measurement of botanical composition of herbage eaten is the nodus all the time. Many methods have been tried, such as manual observation, rumen extrude or faeces detection, examination of oesophageal-extrusa samples and n-alkane technique.