Immuno-castration of female and male pigs with anti-gonadotrophin releasing hormone vaccine: Morphometric, histopathological and functional studies of the reproductive system.

Immuno-castration is increasingly recommended in pigs due to welfare reasons; however, there are few studies in females compared to males. This aim of this study was to investigate the effects of immuno-castration in female and male pigs. The weight, the morphometric and microscopic characteristics of the reproductive organs, and the hormone concentrations were studied in 12 immunocastrated females (IF) and 12 immunocastrated males (IM) and compared with control animals (C). At slaughter, IF tended to have greater body weights than CF (P =  0.051), whereas in IM and CM pigs there were not body weight differences (P =  0.140). The weight of the reproductive tract and size of all individual organs were less in IF compared with CF. Results from histological assessments indicated IF had more atretic follicles and a thinner endometrial mucosa than control females. Hormone concentrations were not different between CF and IF (P >  0.050). As a result of immuno-castration, there was impaired spermatogenesis in most males. Results from microscopic evaluations indicated there was a marked decrease of spermatogonial cells and size of Leydig cells in the testicles. Accessory gland structures were affected in CM and IM with there being differences in gross and microscopic characteristics. Testosterone concentrations, unlike estradiol, were different in IM compared to CM (P <  0.001). These results provide evidence that immuno-castration with the anti-gonadotrophin releasing hormone vaccine is effective in female and male pigs and induces morphological and endocrine changes incompatible with fertility.