Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 20, 2000
Publication Date: N/A
Interpretive Summary: It is well documented that animals exposed to hot environmental conditions eat less and grow slower. It was not known if the reduced growth rate was a result of the hot conditions or only caused by reduced feed intake. An experiment was designed to study the effects of hot conditions separate from the effects of reduced feed intake. It was found that at high levels of heat stress pigs grew at the same rate as pigs at cool conditions but had a larger percentage of fat. However, at moderate levels of heat stress the pigs grew at the same rate and had similar levels of fat.
Technical Abstract: Sixty Large White x Landrace barrows (65.2 plus/minus 0.5 kg) were randomly assigned to one of five treatments: control, two levels of temperature imposed feeding restriction (13%HS, 26%HS) and two levels of manual feed restriction at thermoneutral (13%TN, 26%TN). Feeding behavior was monitored continuously in the control, 13%HS and 26%HS treatment groups. Weekly weights and bi-monthly ultrasound backfats were taken. The pigs were slaughtered at an average treatment 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 found to have significantly higher fat deposition and lower protein deposition than the 26%TN treatment group (P<0.05). Ultrasound backfat indicated similar trends in carcass fat and protein differences.