PRODUCTIVITY, TIME BUDGETS AND SOCIAL ASPECTS OF EATING IN PIGS PENNED IN GROUPS OF 5 OR INDIVIDUALLY

An experiment was conducted to compare the productivity and behavior of growing and finishing pigs penned in groups of five or individually. A total of 160 pigs, 80 male and 80 female, were allotted within sex to 20 pens of five animals and 60 individual pens. Pigs were transferred to larger pens after 4 weeks of the 10 week study. Gain, feed intake and efficiency were determined at 2 week intervals. Four 24 h and four sets of three 6 h observations were conducted to determine time budgets and social aspects of eating in the pigs. Individually penned pigs ate 5.5% more (P<0.05) and gained 4% more (P<0.10) than pigs penned in groups of five. There were no differences in efficiency. Pigs spent approximately 9.7% of the time eating, but this did not differ between group sizes or sexes. Pigs in groups of five spent more time standing than did individually penned pigs (8.35% versus 6.95%, respectively; P<0.05). Eating and standing evidenced a significant diurnal distribution with the peak in activity between 08:00 and 16:00 h. Pigs in individual pens ate at the same time as a neighboring individual pig more often than would be expected by chance. Individually penned pigs adjacent to group pens synchronized their eating with that of pigs in the group pen only if the feeder in the group pen was adjacent to the common pen divider. Within groups of five, pigs ate alone rather than in pairs more often than would be expected by chance. This avoidance appeared to increase with age. Barrows gained more and consumed more feed than gilts (P<0.01), but with the exception of one observation, did not differ in time budgets or diurnal patterns of behavior. Penning in groups of five compared with individual penning reduced intake more in gilts than in barrows. It is hypothesized that increased standing in group pens may be related to the avoidance of others while eating, and contribute to the reduction in production.