[Stilbestrol treatment of the embryo and its influence on the development of the gonads, penis, syrinx und body weight in the muscovy duck, cairina moschata].

In a first experiment 30 fertile eggs of Moscovy ducks were dipped in a solution of 40 mg diethylstilbestrol/100 ml ethanol (95 %) at day 13 of incubation. The treatment caused total suppression of penis development but reduced hatchability to 30%. In a second trial 46 fertile eggs were dipped at day 8 of incubation. In this case only subtotal suppression of the penis was induced; hatchability reached 89 %. In both experiments the left gonad of the males developed to an ovotestis but returned slowly to normal testis structure. The total suppression of the penis and of the bulla ossea was irreversible even after the testis had reached again their normal androgen secretion. There was no influence of the treatment on the marked difference in growth of male and female ducklings.