Testes Weight Is Not A Reliable Tool for Discriminating Immunocastrates from Entire Males

In view of the criticism regarding the piglet castration as currently practiced, one of the alternatives is the active immunisation against the hypothalamic GnRH hormone referred to as immunocastration. This method is effective in prevention of boar taint in pork and has the advantage of avoiding the pain associated with castration (performed without anaesthesia and analgesia). However, in some rare cases the immunocastration may not be effective and such pigs (so called non-responders) present a risk for boar taint. It is therefore important to have a reliable indicator of the effective immunocastration for the use on the slaughter line. Determination of boar taint substances (androstenone and skatole) is time consuming and expensive, whereas the size of reproductive organs could serve as an indicator of successful immunocastration. Present study provides results for 76 immunocastrates (IC) and 55 entire males (EM) varying in body (or carcass) weight and delay between immunocastration and slaughter, in which testes and accessory sex glands (vesicular gland, bulbourethral gland) were dissected and weighed. Gathered data were used to distinguish IC and EM by discriminant analysis. The results show better discrimination of IC than EM. Testes weight is less reliable indicator of successful immunisation than the weight of accessory sex glands and that the best discrimination was achieved when using all three measurements