Texas Tech University

Researchers Earn Grant to Study Stress of Weaning Pigs

George Watson

May 5, 2017


The research hopes to reduce the effects of stress on piglets through use of anti-inflammatory medication.


Though it's not always seen, stress affects almost every mammal on the planet, whether it walks on four legs or two, whether it speaks or not. And stressors come in all shapes and sizes.

For young piglets, one of the biggest stressors is weaning, which brings about a litany of social, environmental and nutritional stresses. And the stronger those stressors on a pig, the more they can restrict its ability to grow and develop at a normal pace by exaggerating the animal's immune responses.

A team of researchers in the Texas Tech University College of Agricultural Sciences & Natural Resources, however, is working to reduce the effects of those stressors on piglets by showing how the anti-inflammatory drug cortisol and its analogs can regulate a pig's immune system, allowing it to grow normally.


To that end, assistant professor Anoosh Rakhshandeh and his collaborators, professor John McGlone and research assistant professor Arlene Garcia-Marquez, all from the Department of Animal and Food Sciences, received a grant for $296,000 from the United States Department of Agriculture's National Institute of Food and Agriculture (NIFA). 

"Weaning is the most stressful period in a pig's life, which results in a post-weaning growth lag and production of less resilient pigs," Rakhshandeh said. "During this period, piglets are exposed to immunological, environmental and nutritional stresses. Our funded research proposal focuses on the use of cortisol analogs (CA) as an alternative to antibiotics. We hypothesized that cortisol analogs mitigate the negative effects of immunological stress and improve digestive physiology and overall productivity and robustness of the newly weaned pigs. In addition, we will explore the underlying mechanism through which cortisol analogs improve the productivity and welfare of piglets."


The goal is to minimize the impact stress has on newly weaned pigs, which could lead to the production of a more robust and resilient pig. Researchers will evaluate the effects of CA on weaning pigs who are fed an antibiotic-free diet under controlled conditions, identify the mechanisms that allow CA to improve growth performance and determine whether it's best to administer the drug through injection or through ingestion of water or food.

Efforts in these research laboratories have already resulted in a significant increase in growth rates and improved feed efficiency for pigs when treated with CA.

"We initially thought that the problem with stress is that there is too much cortisol produced," McGlone said. "When we blocked cortisol, the pigs did not do as well. So we took the opposite approach, even though it may be counterintuitive. When we gave a cortisol-like drug at the time of stress, pig health and growth improved. This provides a novel way to improve pig health and welfare without the use of antibiotics."

The project will then look at expanding CA treatment to the swine industry by repeating these controlled experiments in an industrial setting.

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