The incidence of infertility among domestic animals has been the greatest stimulus towards researches upon the pathology of the genitalia of these animals (Quinlan, 1929, 1935). However, it has been realized for many years that factors also of a non-pathogenic nature are responsible for many irregularities which occur in connection with the functions of the sex organs of farm animals (Heape, 1899, 1901; Marshall, 1903; Hammond, 1914, 1921; Marshall and Hammond, 1926). Detailed studies of sex physiology are elucidating problems which, if solved, would assist farmers in regulating the management and feeding of their stock so as to obtain maximum production during
the full length of the normal life of their animals. Any degree of infertility means economic loss; moreover, the presence of inherent low fertility is transmitted to subsequent generations (Crew, 1925).