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Surgical castration is criticized for welfare reasons. Thus it is necessary to evaluate alternative ways of rearing male pigs such as rearing entire males or immunocastrated animals, and to check that these new production methods do not induce other problemsregarding health or welfare. This study aimed at understanding the effects of testicular hormones on immunity and stress reactivity in pigs.
A total of 65 animals were allocated to 4 experimental groups: entire, castrated at 5/6 days of age, immunized against GnRHor castrated then immunized against GnRH. Blood samples were drawn at 3,4 and 5 months of age to measure sex steroid levels and to analyze populations of lymphocytes. Cortisol was measured in saliva and plasma to evaluate adrenal activity. Pigs were slaughtered at 5 months of age to determine weight of testes, adrenals and thymus.
Results showed higher salivary cortisol in vaccinated males, 24 days after the first injection.Surgical castration also seemed to increase adrenalactivity. Surgical castration seemed to decrease thymic development in pigs (reduced thymicweight at 5 months, decrease in the number of lymphocytes and modifications of sub population percentages in blood at 4 months and in thymus at slaughter).
The effects of immunization against GnRHare less clear.Potential consequences of these changes on global health should be evaluated.
C. Leclercq, E. Merlot, F. Thomas, R. Comte, A. Prunier. Effets de la castration et de l'immunocastration sur l'axe corticotrope et le système immunitaire des porcs. 2012. Journées Recherche Porcine, 44, 79-84.
