Development of a methodology for studying feeding station behaviour of grazing ewes

Abstract

A test apparatus was developed to study feeding station (FS) use and abandonment by sheep, by controlling FS number, characteristics and distance between FS. It consists of a rectangular pen with openings in one of the long sides through which the animal can extend its head to graze. The aims of this experiment were (i) to study FS behaviour of ewes according to the number of FS offered, at two sward heights, and so (ii) to determine the test conditions (FS number, test duration, sward height) most conducive to grazing. Eight dry ewes were offered four grazing treatments (two FS numbers (8 vs. 12) × two sward heights (7 vs. 15 cm)), during four 3-day periods. The ewes were fasted for 17 h and then tested individually for 15 min. A 34-session preliminary training period was necessary to select suitable animals. Behaviour at FS was independent of the FS number, until min 10, when idling increased, particularly for 8 FS and on short sward. A test limited to 10 minutes using an 8-station device seems practical, subject to a sufficiently motivating sward height. FS behaviour was closely related to sward height: grazing time per FS was longer on tall than short swards, which was consistent with field observations and optimal foraging predictions. However, grazing times per FS were much longer in test than in field conditions, which may partly be explained by the absence of fellow animals, a long fast, and constraints of the device.