Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 9, 1998
Publication Date: N/A
Interpretive Summary: The design criteria used for calculating adequate ventilation rates in swine buildings is out of date. A preliminary study was conducted to determine if the values need to be updated. Sixteen barrows from a modern genetic line were subjected to temperatures ranging from 18 to 32C for 22 hours. During this time, respiration gases, feed intake, water intake, and respiration rate were measured. Heat production was calculated from the respiration gases. Feed intake decreased while water intake increased with increasing temperature. It was found that the heat production of the modern genetic line exceeded the current design criteria by up to 30 percent. The respiration rate increased with temperature and was slower during night time hours than during the day.
Sixteen Large White x Landrace high-lean-growth barrows (83.5 +/- 3.2 kg) were acutely exposed to one of four treatment temperatures (18, 24, 28, or 32C) for a period of 22 hours. The barrows had ad libitum access to feed and water during the experiment. During the 22 hr exposure, CO2 production, 02 consumption, moisture production, feed intake and water intake were measured in an indirect calorimeter. Respiration rate was measured every 6 hours by visual observation of flank movement. The calculated heat production was significantly affected by temperature and ranged from 695 to 560 kJ/day kg^0.75. Feed intake decreased at both 28C and 32C. Water intake increased only at 32C. Moisture production increased slightly at 28C; however the greatest increase was at 32C. Respiration rate was affected by both temperature (P<0.001) and time of day (P<0.001) with no significant interaction (P>0.01). The respiration rate increased exponentially with increasing temperature above 18C.