Effect of time of second GnRH vaccination on feed intake, carcass quality and fatty acid composition of male fatteners compared to entire boars and barrows
Sattler, T.; Sauer, F.; Schmoll, F.
Berliner und Munchener Tierarztliche Wochenschrift 127(7-8): 290-296
2014
ISSN/ISBN: 0005-9366 PMID: 25080821 Document Number: 673763
Objective of the study was to evaluate the influence of time point of second vaccination with the GnRH analogon Improvac on growth performance, carcass quality and fatty acid composition of male fatteners compared to surgically castrated pigs and entire boars. The pigs (Piétrain-crossbreds) were divided into two vaccination groups with first GnRH vaccination at eleven weeks of age and second vaccination at 21 (group IA, n = 84) or 18 weeks (IB, n = 83) of age, one group with surgically castrated males (C, n = 90) and one with entire males (EM, n = 91). Body weight, feed conversion rate, carcass quality and fatty acid composition in back fat were estimated. Feed conversion rate until second vaccination was better (P < 0.05) in the vaccination groups (1:2.39) and in group EM (1:2.34) than in group C (1:2.55). Carcass weight did not differ between the groups. Vaccination groups had significantly (P < 0.01) leaner meat (IA: 58.9%, IB: 58.3%) and less back fat (IA: 14.6 mm, IB: 15.5 mm) than group C (56.5%, 17.1 mm). Fatty acid composition was shifted to polyunsaturated fatty acids (PUFA) in back fat in vaccination groups and EM compared to C. The time lag between second vaccination and slaughter had no influence on growth performance, feed intake and carcass quality. C18:3 and C20:2 were significantly (P < 0.01) higher in group IB than in IA, but PUFA did not differ between vaccination groups. GnRH vaccinated fatteners were economically superior to surgically castrated in this study.