Effects of exogenous hormones on the reproductive behavior of adult male domestic ducks. I. Behavioural effects of intramuscular injections

This paper reports the behavioural effects of repeated injections in adult male domestic ducks of pregrant mare serum (PMS), human chorionic gonadotropin (HCG), testosterone propionate (TP), oestradiol monobenzoate (OB) and progesterone (P). The most salient feature of the results was that both gonadotropic hormones had very few effects on behaviour. In particular they did not stimulate the social displays which were, on the contrary, inhibited to some extent by the three steroids including TP. Sexual behaviour was stimulated to a moderate extent by TP and by OB injections (except for copulation which was unaffected by the latter treatment). These results are discussed in the light of comparable studies in mammals and in relationship to the sequence of behavioural and endocrinological events observed throughout a reproductive cycle of untreated animals.