Heat And Moisture Production Of Growing-Finishing Barrows As Affected By Environmental Temperature

Abstract

Heat and moisture production measurements were completed on barrows over the normal weight range of 60 to 120 kg and a temperature range of 16 to 32°C. All measurements were based on a 21-hr period and adjusted to a 24-hr base. Animals were acclimated to treatment temperatures for 2 weeks, and then moved to calorimeters maintained at that respective temperature. After calorimetry was completed, chamber temperatures were adjusted to the next treatment temperature. The process was repeated until all 30 animals were exposed to each of 5 treatment temperatures. Heat production decreased, feed intake decreased, and moisture production increased as environmental temperature increased. Heat production was directly affected by the level of feed intake as measured by the average daily feed consumption over four days prior to calorimetry measures. Dynamic measurements of heat production showed variable increases in heat production dependent on environmental temperature up to the time lights were off, followed by declines in heat production during night time and immediate increases again with lights on, again dependent on treatment temperatures. Measurements on gilts will be completed in a companion study.