Influence of forage availability on feeding station behaviour of ewes

摘要

The grazing process can be considered on the basis of three spatiotemporal scales : bite selection and formation, feeding station utilization and patch selection (Demment and Laca 1993, World Conf on Anim Prod, Edmonton, Canada, 439-460). The objective of the present study is to better understand feeding station (FS) utilization and selection, particularly feeding station residence time (FSRT) and moving between feeding stations. Evolution of FS behaviour was studied during the grazing down process of a reproductive cocksfoot sward (flowerheads appeared). The experiment was conducted from 25 may to 20 June 1994 on a 0.12-ha paddock rotationally grazed by 11 Romanov Limousine dry ewes. Sward surface height (SSH) decreased with time from 373 to 76 mm. Foraging behaviour was measured on 5 ewes three times weekly. Each animal was video recorded one after the other in a predetermined order during 5 minutes and four times during the evening meal. Then we encoded steps and head position to determine FS and moving type. We defined FSRT as the time intervals between two successive steps except i) those during which animal kept its head up and ii) those shorter than 1 s considered as only travelling.