Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 20, 2000
Publication Date: N/A
Interpretive Summary: The energy usage of modern lean pigs was studied under high temperature conditions. The metabolism of the animals was measured at high and cool temperatures, where each group of pigs was given the same amount of feed. Pigs in the cool conditions used more energy, probably due to more heat lost and more activity than pigs at high temperatures. However, the hotter rpigs used the energy that was saved to form fat tissue. Weights of the organs were less as the amount of feed given was reduced. At equal levels of eating, there were no differences in the weights of organs among different temperatures.
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 heat stress (HS) imposed feeding restriction (13%HS, 26%HS) and two levels of manual feed restriction at thermoneutral (13%TN, 26%TN). Three measurements of heat production and activity (standing, lying, eating) were made during the trial. The pigs were slaughtered at an average treatment weight of 107.5 kg. All organs were collected and weighed. Heat production (P<0.0001) and activity (P<0.05) were significantly different for the different treatments. The thermoneutral treatments (control, 13%TN, and 26%TN) had the highest heat production values. These treatment groups also spent significantly less time lying than the heat stress treatment groups (P<0.05). The 13%TN and 26%TN pigs tended to spend more time standing (P<0.10) than the respective HS treatments. The liver weights tended to be esmaller for the 26%TN and 26%HS treatments (P=0.10). The 13%HS and 26%HS treatment groups had significantly smaller empty stomach and small intestines (P<0.005). The 26%TN treatment group also had significantly smaller empty small intestines. Empty caecum was significantly smaller in both the 13%TN and the 26%TN treatment groups.