Effect of immunocastration on carcass and meat quality in boars, barrows and gilts

The aim of this study was to assess the effect of sex and immunocastration and their interaction on carcass and meat quality of finishing pigs in a 3 x 2 study (sex x IC). Forty boars (BO), 40 barrows (BA) and 40 gilts (GI) were raised in individual pens. Each sex was divided in 2 groups of 20 animals, the control (C) and the immunocastrated (IC) group. The IC group received two injections (at 70 kg and 105 kg) of Improvac®, an anti-GnRH vaccine. The pigs had free access to water and were fed ad libitum with the same three phase diet. They were slaughtered at an average live weight of 135 ± 4 kg (mean ± standard deviation). The effect of sex on carcass and meat quality was assessed in the subset of control animals with sex as fixed factor. The effect of IC was assessed separately in each gender subset (BO, BA and GI) with IC as fixed factor. The experiment confirms the known sex differences. In line with literature, dressing percentage of BO was lower compared to BA and GI. Meat percentage of BO and GI was higher and backfat thickness and IM fat content lower compared to BA. Drip loss was higher in BO compared to BA. Meat of BA was less yellow compared to meat of GI. In BO, the higher feed intake after IC led to higher backfat thickness resulting in a lower meat percentage, without affecting intramuscular fat content (IMF). The meat of IC BO was less red compared to C BO and tended to have higher cooking loss and a lower ultimate pH. In gilts, immunocastration tended to increase backfat thickness and decrease meat percentage. IC GI showed improved meat quality compared to C GI with lower shear force values and a tendency to higher IMF. In barrows, IC had only minor effects. IC BA tended to have a lower ham angle and more yellow and red meat compared to C BA.