2012 Annual Report
1a.Objectives (from AD-416):
To systematically update the heat and moisture standards for model swine production conditions.
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 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 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 CO**2** 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.
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. Heat production is significantly influenced by genetics, nutrition, and thermal environment.
Heat and moisture production 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). 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 HMP values which will ultimately replace the HMP values that are currently published in the standards book.
The grant was written in conjunction with a scientist at Iowa State University (ISU), 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. In addition, the grant did support 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.
Iowa State University (ISU) visited the site to calibrate the fans for the final time, to complete the data collection phase in the swine facilities. Personnel from ISU worked to summarize all facility data. A scientist from ISU developed macros within excel to calculate ventilation rates, and heat and moisture production rates. The macros built a data file that included animal weights, waste handling system, environmental conditions, heat production, and moisture production; this data file will be analyzed. A research associate at U.S. Meat Animal Research Center (USMARC), will be completing the data analysis over the next year.