Sexual behavioural pattern of orchidectomised and hormone replaced weaner pigs

Abstract

The persistence or cessation of sexual behaviour after abrupt testosterone withdrawal i.e. castration depends among other things on the age of the animal at castration. The aim of this work is to ascertain the effect of early orchidectomy and subsequent hormone replacement to 24 weeks of age on restoration of sexual behaviour in pigs. Five weeks olds male weaner pigs, 24 in number, randomly grouped into two, twelve in each group were used for this study. The first group was not orchidectomised and not given any form of hormone injection (control). The second group was orchidectomised and given Testosterone enanthate and Oestradiol benzoate hormone replacement respectively (CHR). Orchidectomy was carried out at 5 weeks of age using standard procedure. There was no significant difference in the numbers of subjects mounting in both cases. Whereas only 17% had intromission in the control while 33% had this in the CHR. The control had 0 % ejaculation while 33% ejaculated in the CHR. Sexual behaviour index differs significantly between the two groups with the higher value in the CHR, 2.18±0.10 and 1.56±0.05 in the control. There were no significant difference in the strutting and restless/slashing in the CHR in the control , Violent/biting behaviour was in the control involving all the subjects, 100%, while 83% displayed this in the CHR. Aggressive index is higher in the control than in the CHR, 2.70+0.100 and 2.55+0.05 respectively. The study showed than the CHR (castrated with hormone replacement) group displayed improved  sexual behaviour the than control group, although, the latter group was more aggressive.

Keywords: Hormonal replacement, Orchidectomy, Weaner pigs, Sexual behaviour