FEEDING PATTERNS AND SWINE PERFORMANCE IN HOT ENVIRONMENTS

Two experiments were conducted to determine modifications in eating be havior of heat-stressed pigs using gilts and barrows. Heat-stressed pi gs were maintained at environmental temperatures that caused voluntary 13% and 26% reductions in daily feed consumption compared to control temperature pigs of the same weight. For control temperature pigs, the re was a 50% reduction in number of meals and a threefold increase in meal size as animals grew from 40 to 100 kg. The number of daily meals and rare of eating (g/min) for heal-stressed pigs were remarkably sim ilar to control pigs of the same age. However for heat-stress treatmen ts, the duration of meals was substantially reduced which apparently w as the primary method of behaviorally adjusting to heat stress. Neat s tress reduced liver, heart, stomach, and large intestine weights, and tended to reduce backfat thickness indicating that pigs under hear str ess had reduced maintenance requirements. Heat stress did not affect f eed conversion, but substantially reduced rare of gain.