EFFECT OF A GNRH-ANALOG ON TRAITS OF GROW TH, BODY DEVELOPMENT, MUSCLE STRUCTURE, MEAT QUALITY AND BLOOD TRAITS AT YOUNG BOARS

The aim of this study was to influence the sexual function and develop ment of boars (135 days old) by implantation of a GnRH-analogue (GnRH- a) in depot formulation (Decapeptyl(R) - CR, FERRING, Malmo, Sweden). The following parameters were compared between treated (n=18) and untr eated animals (n=20): Sexual hormone levels (luteinizing hormone, test osterone and estradiol-17 beta) in peripheral blood and the content of 5 alpha-androst-16-en-3-one in body fat, traits of fattening, muscle structure, carcass performance, blood traits, weights and measures. Th e experiment was finished at the 28th day after GnRH-a injection. By t he influence of the GnRH-a the concentrations of reproductive hormones and androstenone were reduced in comparison with the untreated contro ls. In accordance with this effect the size of testes was decreased. T here was a positive correlation between testosterone concentration and muscle fibre growth. The course of growth and also the parameters of carcass and meat quality and blood traits did not differ between both groups of animals. Altogether, the treatment of boars by GnRH-a in dep ot formulation induced an effect of castration without impairment of c arcass quality.