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
The heat and moisture production (HMP) data currently being used for ventilation design and environmental control of animal facilities are mostly 30 to 50 years old (ASHRAE, 2005; ASAE, 2003; CIGR, 1999). Fifty years ago, pigs were almost exclusively raised outdoors; today, pigs are predominantly raised indoors to improve food safety, manure management, handling ease, animal well-being, and performance. Raising pigs indoors requires extensive engineering and animal expertise. Many years of research have been dedicated to building design and understanding the interaction between the building and animals. Important criteria in facility design are animal HMP. An animal’s heat production (HP) is a product of the inefficiencies related to breakdown and use of food stuffs. HP is significantly influenced by genetics, nutrition, and thermal environment. HMP rates are important criteria in building design. These HMP values provide the basis of design capacity for fans and heaters to control temperature and moisture in buildings. Temperature and humidity control are important, not only to maximize animal well-being and production, but also to prolong the life of the structure. Environmental temperature and animal size effects on HMP values are documented in published standards (ASAE Standards, 2003; ASHRAE, 2005). The unit received a grant from ASHRAE (American Society for Heating Refrigeration, and Air Conditioning Engineers) to conduct a series of studies to update the swine HMP values which will ultimately replace the numbers that are currently published in the standards book. The grant will be partially completed through 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. In addition, the grant will support a series of field measurements to include a range of ages from farrowing, nursery, finishing, and gestating. The objective of the field measurement is to collect field scale moisture production and verify THP data collected in calorimeter laboratory studies. Currently, we have completed the four calorimetry laboratory studies. One experiment using 96 nursery pigs was conducted; pigs were subjected to four environmental temperatures (20, 25, 30, and 35°C). A second experiment using 48 growing pigs was completed using temperatures of 18, 23, 28 and 33°C. Two experiments were conducted using 30 finishing barrows and 30 finishing gilts; the temperatures ranged from 16 to 32°C. The results of these lab-scale experiments are being summarized. Data summarization and analysis will need to be completed. The field measurements are currently in the planning phase. Modifications are being made to production facilities so measurements can be taken.