1a. Objectives (from AD-416):
To systematically update the heat and moisture production standards for all phases of swine production.
1b. Approach (from AD-416):
The experiment will be conducted using two different protocols for the two different components of the experiment. The first component’s objective will be to determine the total heat production (THP) of the various ages of pigs. The second component will focus on updating the moisture production (MP) of the production system. The first component will be conducted in four separate experiments using a total of 204 pigs, and will evaluate the total heat production response of the moderately acclimated pigs to temperatures ranging from cool to hot. The first experiment will utilize a total of 96 nursery pigs that will be selected at weaning. The pigs will be placed 4 pigs to each pen in one of four environmental chambers set to one of four temperature treatments (20, 25, 30, 35 °C). The second experiment will be conducted with a total of 48 pigs penned two pigs/pen in one of four environmental chambers set to one of four temperature treatments (18, 24, 29, 33 °C). The third and fourth experiment will be conducted using a total of 30 pigs per experiment individually penned in one of five environmental chambers set to one of five temperature treatments (16, 20, 24, 28, or 32°C). After a 1 to 2 weeks adaptation to the assigned environmental temperature, each pen of pigs will be moved to the adjacent indirect calorimeters operated at the same temperature and humidity for a 22-hour period. During this time total heat production and an estimate of moisture production will be measured by indirect calorimetry methods, data will be collected every 10 minutes in addition to a composite sample taken over the entire 22-hours. Animals will change temperament treatments will be changed after each calorimeter measurement. The second component will be conducted in a production system to determine MP by both the pigs and the housing systems. Two swine houses located at the USMARC will be used for these studies. Air temperature, RH, and CO2 concentration of both inside and outside will be recorded at 15-min intervals for a 24 hour period at least one time a week for the duration of the production cycle. Prior to initiation of the experiment each of the exhaust ventilation fans will be calibrated in-situ at various static pressures to develop the actual fan performance curves. Operational status of each exhaust fan will be monitored continuously. THP and MP data will be fitted to regression models each for barrows and gilts with main effects of temperature and body weight, using appropriate interaction, linear, and quadratic terms.
3. Progress Report:
Environmental temperature and animal size effects on HMP values are documented in published standards (ASAE Standards, 2003; ASHRAE, 2005). A grant was received from ASHRAE (American Society for Heating Refrigeration, and Air Conditioning Engineers) to conduct a series of studies to update the swine heat and moisture production (HMP) values which will ultimately replace the HMP values that are currently published in the standards book. The grant was written to support four calorimeter laboratory studies, with the objective of collecting total heat production (THP) from both barrows and gilts ranging in size from nursery age pigs through slaughter weight. The grant supported a series of field measurements, which included a range of ages from farrowing, nursery, finishing, and gestating. The objective of the field measurement was to collect field scale moisture production and verify our THP collected during the calorimeter laboratory studies. The laboratory studies and field measurements have been concluded, the data have been summarized and a final report and a publication have been submitted. Overall, HP was found to be 16% higher than current standards. In order to predict moisture production (MP) from the entire facility rather than just the animals, the waste handling systems, sprinkle cooling systems, and non-vented gas-fired heaters were monitored and found to contribute significantly to the overall MP. Continuous measurements showed a diurnal HP pattern that was higher during light than dark periods, with peaks just after lights came on and just before lights went off. With this data, equations to predict HMP from the pigs have been generated. In addition, prediction of the building’s contributing moisture has been estimated at 51g hr-1 m-2. With these updated HP and MP equations and the estimation of the building component of moisture production, the standards for heat and moisture production can be updated. Updated standards will ensure new swine facilities have properly sized fans and heater systems which contribute to adequate climate control and increase building life. The remaining objective on this grant is presentation of the results, which is scheduled for January, 2014.