Methods for measuring feeding motivation in sheep

The effects of food restriction on the welfare of sheep are as yet unclear. An operant crate and a push-door were used to measure feeding motivation i n sheep after 0h, 6h, 12h, 18h and 24h without food. In experiment I, sheep had to push a panel with their noses to obtain a food reward. In experimen t 2, sheep had to run a race and push through a weighted door to reach food ; the time taken to reach various points was recorded and the work performe d to push through the door was calculated In experiment 1, 3 out of 12 sheep became trained to push the panel and the re was a difference in the mean number of rewards/session obtained by each animal (P < 0.05). There was no effect of treatment on the number of panel presses performed. In experiment 2, 10 out of 14 sheep were successfully tr ained. More sheep went through the push-door when deprived of food (P < 0.0 5), and they were quicker to enter the race, reach the push-door, and reach the food than those which had not been deprived (P < 0.0001). They also sp ent less time pushing the door than non-deprived sheep (P < 0.0001). The push-door was a more appropriate method of measuring motivation to feed in sheep, as more sheep learned the task in less time than for the operant crate. As measured by the time taken to enter the race, reach the push-doo r, push through the door and reach the food there was an increase in feedin g motivation after only 6h without food.