Effect of terminal sire line and timing second vaccination on effectiveness of immunocastration, performance, and
E Kowalski1, E Vossen2, S Millet3
1Flander Research Institute for Agriculture, Fisheries and Food (ILVO), Animal Sciences Unit, Melle, Belgium; Ghent University, Laboratory for Animal Nutrition and Animal Product Quality, Department of Animal Sciences and Aquatic Ecology, Ghent, Belgium.
Abstract:
Performance (from 10 weeks until slaughter), carcass and meat quality, and effectiveness of immunocastration was compared in crossbred offspring of stress positive (BP+) and negative (BP-) Belgian Piétrain and Canadian Duroc (CD) given the second vaccination of Improvac® at different times (4, 6, 8 weeks before slaughter). CD offspring had a significantly higher daily gain (DG) and feed intake (DFI), and lower predicted lean meat percentage (LMP) and dressing yield compared to BP+ and BP-, while feed conversion ratio (FCR) did not differ. CD offspring had significantly lower drip loss and higher pHi, intramuscular fat content than BP+ and BP- (except for pHi). No significant effect of vaccination time on DG nor FCR was observed. Predicted LMP tended to increase as time-post injection decreased, while meat quality was minor affected. Earlier vaccination had no effect on the effectiveness of immunocastration based on testosterone and GnRH-binding.
