EFFECT OF IMMUNOCASTRATION (IMPROVAC®) IN FATTENING pigs II: CARCASS TRAITS AND MEAT QUALITY

The effect of immunocastration (vaccination against gonadotropin releasing hormone using Improvac® vaccine) on carcass and meat quality traits of Slovenian commercial fatteners was studied. The experimental pigs were selected from 35 litters (2 castrates and 3-4 boars per litter) farrowed within two weeks period and assigned to three treatment groups: boars (n=25), immunocastrated (n=24) and surgically castrated males (n=25). Vaccination of pigs was performed twice; at 10 and 19 weeks of age. Pigs were slaughtered at 24 weeks of age (two slaughter batches in two consecutive weeks) according to the routine abattoir procedure. Various carcass and meat quality traits were assessed. Additionally, an olfactory evaluation of meat for the presence of boar taint was performed using a six member panel. Differences between treatment groups were detected for fat tissue measurements and ratio meat to fat in ham and on the cross-section at the level of last rib or neck. In comparison to the surgically castrated males (the fattest) and boars (the leanest), the immunocastrated males took an intermediate position. However, they were mainly closer to the boars as to the surgically castrated males, except in one case (neck fatness) where immunocastrates were closer to surgical castrates. No significant differences between treatment groups were noted for pH value, colour or drip loss. Regarding intramuscular fat which is important for sensory quality, we noted a significant difference between surgical castrates and boars, whereas the immunocastrates were either intermediate (biceps femoris marbling) or closer to boars (longissimus dorsi intramuscular fat). The present study provided additional evidence of the benefits of the immunocastration for carcass quality, with no major effect on meat quality.