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United States Department of Agriculture

Agricultural Research Service

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Research Project: HEAT AND MOISTURE PRODUCTION RATES FOR MODERN SWINE AND THEIR HOUSING SYSTEMS

Location: Nutrition and Environmental Management Research

2010 Annual Report


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. Temperature treatments for animals 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

Heat and moisture production (HMP) rates of animals are important criteria in building design. 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. 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.

Heat and moisture production (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 Refrigerating, 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 ASHRAE standards book.

The grant was rewritten 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 through slaughter weight pigs. In addition, the grant will also support a series of field measurements of animals at farrowing, nursery, finishing, and gestating stages. The objective of the field measurement is to collect field scale moisture production data and verify our THP data collected during the calorimeter laboratory studies.

This year we installed instrumentation to record temperature, humidity, and carbon dioxide levels for air coming into and exiting one small building. This allows calculation of heat and moisture production data. This building is being used to house pigs from nursery age to gestating sows. During the second quarter of 2010, a series of measurements on gestating gilts and sows were completed. Eighty bred gilts/sows were moved into a swine building at approximately 30 days of gestation. The measurements were made until the first group of animals was moved out at 110 days of gestation.


Last Modified: 12/19/2014
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