Scientists are looking at the levels of stress hormones in the hair of pigs as a means of identifying which genetic lines will be more or less resilient in warding off disease.
Researchers with Iowa State University, the Universities of Saskatchewan and Alberta and CDPQ are measuring the levels of stress hormones in the hair of pigs to evaluate the effect of stress on performance and disease resilience and compare the response of different genetic lines to stress.
Dr. Jack Dekkers, a distinguished professor in the Department of Animal Science at Iowa State University and the Principle Investigator in the USDA funded project exploring retroactive measures of stress in swine hair and the genetics of disease resilience in swine, explains hair samples from about one thousand pigs were collected and analysed about three weeks after weaning, about six weeks after the pigs were exposed to infection and again just before going to market.
Clip-Dr. Jack Dekkers-Iowa State University:Click here to see more...
When we're exposed to stress there are stress hormones that are increased, in particular cortisol, a hormone with the abbreviation DHEA (Dehydroepiandrosterone) and cortisone, you get elevation of those stress hormones in blood and animals that are more stressed, they get higher levels of those hormones.
As your hair grows some of those hormones get deposited in hair, depending on what the level in blood is at that time.
When you look at stress hormones in blood they fluctuate a lot but in hair you get an accumulation of every time point.
If you look at the hair that was grown over a six-week period, that reflects the response to stress over that entire period.