THE COMPOSITION OF THE STALLION'S SEMEN

Abstract

SUMMARY The composition of the semen of the stallion was studied by microscopic and chemical methods and the extent of fluctuations in the same animal has been determined. Two characteristic constituents of the seminal plasma of the horse, ergothioneine and citric acid, have been shown to originate in the ampullae and seminal vesicles respectively. With the aid of chemical methods for the analysis of semen it has been possible to obtain a general quantitative indication of the contribution of the ampullar and vesicular secretions towards the final composition of normal stallion ejaculates. By the method of fractionate collection of semen, an attempt was made to determine the sequence with which the different portions of the semen of the stallion are ejaculated. It has been demonstrated that the sperm-containing fraction is rich in ergothioneine but not in citric acid, and that it is followed by a post-sperm fraction, which has a high content of citric acid and consists mainly of the vesicular secretion. The seminal characteristics of the jackass have been shown to resemble those of the stallion.