Castration in the Swine Industry and the Impact on Growth Performance – Physical versus Vaccination

In most parts of the world, male pigs that are destined for the market are physically castrated very soon after birth in order to reduce the risk of boar taint. However, entire male pigs are more efficient and deposit less fat than barrows, particularly at high slaughter weights. Also, animal welfare activists are lobbying for a cessation of physical castration in many parts of the world, particularly the EU, with a high likelihood that this could lead to inferior pork and processed products. A welfare friendly alternative is vaccination against gonadotrophin releasing factor (GnRF) which allows producers to capitalise on the superior natural growth and carcass characteristics of intact boars without the risk of boar taint. Vaccination against GnRF results in superior feed efficiency and carcass lean yield over physical castration, while maintaining pork eating quality. There have been very few studies that have compared the lysine requirements of boars and barrows, and none with contemporary genotypes. Recent data suggests that the lysine requirement of boars is slightly higher (ca. 0.6 to 0.9 g/kg) than for gilts and barrows. Given that the penalty in growth performance for having inadequate dietary lysine is greater in boars than in gilts or barrows, it is important to ensure that dietary lysine requirements are met to obtain the maximum benefits of boar production coupled with vaccination against GnRF.