Social facilitation in teat-fed calves

Abstract

The importance of social facilitation in feeding has been demonstrated in many species. The following experiment was designed to investigate its occurrence in teat-fed calves in different social environments. A 10-day-old calf (Calf A) was exposed to 3 treatments on consecutive days: (1) completely isolated (C.I.) by being penned alone in an empty building; (2) spatially isolated (S.I.) by being penned individually with another calf (Calf B) present in an adjoining pen, both calves fed simultaneously; (3) penned together (P.T.) by being penned with Calf B which was muzzled to prevent it sucking at the teat. Milk was offered ad libitum to Calf A twice daily (and Calf B in the S.I. treatment), and the amount drunk and the behaviour of the calf were recorded. In each case, Calf A was also fed 3 1 of milk replacer before the recorded feeding periods in order that B would be hungrier. The procedure was repeated on 8 calves. The mean daily milk intakes for the treatments (C.I., S.I. and P.T.) were 5.5, 7.5 and 9.2 l, respectively. The P.T. and S.I. values were significantly greater than the C.I. values (P < 0.01 and P < 0.05, respectively). There was no difference between treatments in sucking bout duration or drinking rate. However, there was a significant increase through the treatments (C.I., S.I. and P.T.) in the mean length of the total daily feeding period (12.9, 18.4 and 23.8 min, respectively, P < 0.01), and a similar increase in the daily duration of sucking (487, 724 and 864 s, P < 0.05). These results suggest that the increase in milk intake observed in the more social situation is due to an increase in the time spent sucking rather than an increase in the rate of drinking. More specifically, this would appear to be due to an extension of the feeding