A multi-institutional team of scientists has identified a gene that breading companies can select for as an indicator of disease resilience in pigs. Researchers with Iowa State University, the Universities of Saskatchewan and Alberta and CDPQ, with funding from PigGen Canada, Genome Alberta, Genome Prairie and the U.S. Department of Agriculture, are measuring the levels of stress hormones in the hair of pigs to evaluate the effect of stress on disease resilience.
Dr. Jack Dekkers, a distinguished professor in the Department of Animal Science at Iowa State University, says researchers have found that cortisol in hair has a heritability of about 25 percent.
Quote-Dr. Jack Dekkers-Iowa State University:
If you look at growth rate in pigs, heritability is a little bit higher at about 35 percent so 25 percent is a pretty good heritability and that means that there are measures that breeding companies can select for.We have also looked at some associations of cortisol levels in hair measured on the young healthy animals and their subsequent disease resilience and there are correlations we find there so there is an indication that cortisol levels in hair can be a predictor of whether an animal is more or less disease resilient.
Interestingly for cortisol levels in hair, we find that it is affected by many genes that control growth rate.Same for cortisol levels but there is one gene that has a substantial effect.We call that a major gene.It explains about 40 percent of the genetic variation, the genetic differences.That's a gene called a glucocorticoid receptor which is known to be associated with cortisol release and production.That gives us a single gene that the breeding companies may be able to select for.
Dr. Dekkers notes animals that are less resistant to disease require more veterinary treatments increasing the danger of pathogens developing resistance to antibiotics.
Source : Farmscape.ca