Growth performance, carcass characteristics and meat quality of group-penned surgically castrated, immunocastrated (Improvac®) and entire male pigs and individually penned entire male pigs

Abstract

The objective of the study was to compare growth performance, carcass characteristics, meat quality and fatty acid composition of the adipose tissue of group-penned barrows, immunocastrated boars and entire males. Furthermore, the effect of housing of entire males on the aforementioned parameters was evaluated. At 55.2 days of age, 52 Swiss Large White pigs were blocked by litter and assigned by BW to four experimental groups: barrows (C), immunocastrated boars (IC), entire males (EMG) reared in group pens and entire males (EMP) reared in individual pens. In experiment 1, the effects of the method of castration were investigated (experimental groups C, IC and EMG). In experiment 2, the effects of housing on entire male pigs were evaluated (experimental groups EMG and EMP). All pigs had ad libitum access to standard diets from weaning to 107 kg BW. The two vaccinations (Improvac®) were applied to the IC pigs at an average BW of 22.6 and 73.0 kg. In experiment 1, average daily gain (ADG) did not (P > 0.05) differ among the experimental groups. However, EMG consumed less feed and had a better feed-conversion ratio than C (P < 0.001 for each). For IC, intermediate values were observed, which differed (P < 0.001) from EMG and C. Lean meat percentage decreased (P < 0.05) from EMG to IC, and from IC to C. The androstenone and skatole levels were higher (P < 0.05) in the adipose tissue of EMG than IC and C. Shear force values were higher (P < 0.01) in the longissimus muscle of C and EMG, compared to IC. The concentration of saturated fatty acid in the adipose tissue increased (P < 0.001) from EMG to IC, and from IC to C pigs, and that of polyunsaturated fatty acid decreased (P < 0.001). In experiment 2, ADG did not (P > 0.05) differ between EMP and EMG. However, EMP pigs consumed more feed than EMG pigs and had a poorer feed efficiency (P < 0.01 for each). In conclusion, EMG pigs had a better feed efficiency than IC pigs and their carcasses were leaner, but the risk of boar tainted pork was elevated. Group-housing negatively affected average daily feed intake but not ADG of entire males. At the moment, immunocastration offers a good approach to avoid castration and minimize the risk of boar taint.