CHAMPAIGN, Ill. -- Environmental stresses slow the rate at which pigs grow to market maturity. A new study has found that the stresses are additive and, therefore, predictable in their impact. Such knowledge, researchers say, may help improve management on hog farms.
Researchers subjected groups of Yorkshire and Hampshire crossbreds and purebred Durocs to three commonly occurring environmental stresses -- heat, overcrowded pens and regrouping -- in various combinations over four weeks. When all three conditions existed concurrently, the pigs' growth rate fell by 31 percent compared with pigs in the control group that was free of stressors. For pigs subjected to the three stressors individually, growth rates fell by 10 percent, 16 percent and 11 percent, respectively.
The University of Illinois study -- the first measuring the effects of more than two stressors occurring simultaneously on swine -- was published in the March issue of the Journal of Animal Science by Rodney W. Johnson, Mike Ellis and Y. Hyun of the U. of I. department of animal sciences and Gerald Riskowski, a professor of agricultural engineering. It was funded by the National Pork Producers Council and Cargill Inc.
Pigs often face a variety of other environmental stresses on hog farms, but the study clearly suggests that many stresses are additive in nature, thus predicting the detrimental effects of multiple stresses may now be possible, Johnson said.
"Animal environments are very complex," he said. "Of course, the ideal management strategy is to remove stressors from the environment. Pigs will eat more and grow faster as a result. However, the reality is that not all stressors are controllable."
Heat stress on summer days, in which temperatures in pig pens may reach
28 to 34 degrees Celsius (82 to 93 degrees Fahrenheit), is often uncontrollable
in that applicable cooling systems are not entirely effective, and air-conditioning
for an entire pig facility is fin
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Contact: Jim Barlow, Life Sciences Editor
b-james3@uiuc.edu
217-333-5802
University of Illinois at Urbana-Champaign
4-May-1998