Bones, reproductive organs and carcass characteristics of entire, early and late immunocastrated male pigs

Immunocastration has been introduced in pig production in order to combine the reduction of undesired characteristics of meat and improvement of animal welfare with achieving the highest possible production results. Although previous research has examined the influence of immunocastration on production parameters, carcass quality and reproductive organs, there is limited information available regarding its impact on bone characteristics. The aim of this study was to evaluate the effects of producing entire male pigs and pigs following two immunocastration protocols on growth performance, sexual organ development, carcass quality, total bone properties and radius characteristics as determined by computed tomography images. Entire males (EM), early immunocastrated animals (EIC, first vaccination-V1 13 weeks before slaughter and second vaccination-V2 8 weeks before slaughter) and late immunocastrated animals (LIC, V1 8 weeks before slaughter and V2 4 weeks before slaughter) did not differ in daily gain and final weight. However, daily feed consumption (after V2 of EIC), feed conversion ratio (after V2 of LIC), fat thickness (after V2 of LIC) and ham fat thickness and area (measured in the carcass) were the highest in EIC animals, the lowest in EM animals, with LIC being in between. Reproductive organs length and weight were significantly decreased by immunocastration, with smaller sizes observed the longer the immunocastration lasted. Yellowness of the testes increased with immunocastration, while redness and lightness seemed to increase at the beginning of the immunocastration and decrease as time went on. Minor differences in bone characteristics in EIC compared to entire males were observed. Only the proportion of high-density (P = 0.092) bones tended to be higher in EIC than EM pigs, while the proportion of very high-density bones (P = 0.035) was significantly higher in EIC than EM pigs. Under the conditions of the present work, overall bone mineral density, radius length and radius cross-sectional area were not influenced by the timing of immunocastration in this study, eliminating the possibility of removing animals from production/fattening due to problems with the skeletal system.