Manual and thermal induced feed intake restriction on finishing barrows. I: Effects on growth, carcass composition, and feeding behavior

A study was completed on the effects of heat stress on growth, carcass comp osition, and feeding behavior of finishing barrows without the compounding effect of a reduced feed intake. Sixty Large White x Landrace barrows (65.2 0.5 kg) were randomly assigned to one of five treatments: control, two lev els of temperature imposed feed intake restriction (13% HS, 26% HS), and tw o levels of manual feed intake restriction at thermoneutral (13%TN, 26% TN) . Feeding behavior was monitored continuously in the control, 13% HS, and 2 6% HS treatment groups. Weekly weights and bi-monthly ultrasound backfats w ere taken. The pigs were slaughtered at a treatment average weight of 107.5 kg. The offal and the left half of the carcass were ground separately and analyzed for protein, fat, water and ash. The 26% HS treatment group was fo und to have significantly higher fat deposition and lower protein depositio n than the 26% TN treatment group (P < 0.05). Ultrasound backfat indicated similar trends in carcass fat and protein differences. Results suggest that high-lean-growth pigs reared in hot environments deposit more fat and less protein than those raised in a thermoneutral environment and fed similar a mounts.