Effects of confinement on rebounds of locomotor behaviour of calves and heifers, and the spatial preferences of calves

Abstract

An open-field test and a preference test were used to investigate the motivation of calves and heifers to perform locomotor behaviour. Thirty-six calves and 48 heifers were housed in large pens for a pre-period of 2 weeks. During the last week of the pre-period, all calves were subjected to a 10-min open-field test where locomotor behaviours (walking, trotting, galloping and bucking) were recorded. The spatial preferences of 28 of the calves were also measured in a maze where they could choose between a large (21 m 2) and a small (2.4 m 2) goal room in six successive tests (runs). During the experimental period, calves and heifers were confined and thus deprived of the opportunity to perform locomotor behaviours for either 4 weeks, 2 weeks or 1 week immediately before being tested, or they stayed in the large pens for the whole period (control). All calves and heifers were subjected to the 10-min open-field test and 28 of the calves were subjected to the spatial preference test two days later. Finally, a third test was conducted in which 21 of the calves could choose between the large room and the small room containing a small amount of food. During the open-field test after the experimental period, confined calves galloped and bucked more than control calves (19.4, 17.1, 11.4 and 4.4 s for treatments 4wk, 2wk, 1wk and control; P<0.01), and more confined heifers were observed galloping or bucking (10/12, 6/12, 7/12 and 3/12 for treatments 4wk, 2wk, 1wk and control; P<0.05). These results suggest that confinement increases the motivation to perform locomotor behaviour. The calves showed a preference for the large room over the small room both before and after the experimental period, but there was no effect of treatment. The median latency to enter either of the two rooms increased over runs in the test before the experimental period (17, 22, 7, 48, 108, 63 s for runs 1, 2, 3, 4, 5 and 6; P<0.001) and in the test after the experimental period (17, 30, 41, 44, 84 and 64 s for runs 1, 2, 3, 4, 5 and 6; P<0.001). In the final preference test, the calves showed a clear preference for the small room containing food and the latency to choose was short and constant across runs (3 s). The results of the preference tests show that calves preferred to stay in a large room when given a choice, although this spatial preference may change in favour of food.