A METHOD FOR INTRODUCING PIGS INTO FREE-ACCESS TWO-LEVEL PENS

Groups of 12 grower pigs were housed in a two-level pen in which a short ramp gave access to an upper level for feeding and resting. Two experiments studied the behavior and performance of pigs when introduced into the pens in two different ways. Twelve groups were herded into the lower floor and were allowed to climb the ramp at will. Most did so, but 12 of the 144 animals had to be forced up the ramp the first time. Compared to matched groups in conventional pens, pigs in the two-level pens ate 9.5% less feed in the first 3 d (P < 0.01) and gained 0.5 kg less weight in the first week (P < 0.025). Twelve other groups were driven directly up the ramp and were confined on the upper level for the first 3 d, with the ramp pinned in a horizontal position to form a temporary dunging area. With this procedure there was no initial depression of feed intake, little effect on initial weight gain, no need for the manager to identify "ramp-shy" pigs, and little accumulation of manure on the upper level. The procedure is recommended for introducing pigs into two-level pens. Key words: Pigs, pen design, weight gain, feed consumption, animal welfare