Relationship of Hyaluronidase Concentration to Fertility of Dairy Bull Semen

Abstract

The possibility that the concentration of the enzyme hyaluronidase in mammalian semen is a critical factor in fertility has led the authors to investigate this relationship in dairy bulls. In fertility studies in rabbits, Rowlands (8) found that by adding seminal plasma from killed spermatozoa suspensions containing hyaluronidase to dilute spermatozoa suspensions the median effective spermatozoa concentration for fertility was reduced to one-sixth of that of the controls. In similar experiments, however, Chang (1) indicated that the increased fertilizing capacity obtained by adding seminal plasma to dilute suspensions of spermatozoa was not due to hyaluronidase but to some other seminal plasma factor. Seminal plasma in which the hyaluronidase had been inactivated by heat was similarly effective, whereas added bull testes hyaluronidase had no effect. Kurzrok et al. (5) reported that in six cases of human female infertility where the female was apparently not at fault and where the male seminal hyaluronidase concentration was low, the application of bull testes hyaluronidase to the uterine cervix with subsequent coitus resulted in pregnancies. Later, Kurzrok (4) reported that 33 out of 102 similar clinical patients conceived following the application of bull testes hyaluronidase to the uterine cervix. Entirely negative results were obtained by Seigler (10) in a series of 48 cases of human female infertility where hyaluronidase was applied and where the female presumably was not at fault. Semen samples from the male partner were not assayed for hyaluronidase in these cases. A zero order correlation coefficient of -0.32 (significant at the 5 per cent level) between hyaluronidase titer and fertility of dairy bull semen was obtained by Sallman and Birkeland (9). The hyaluronidase assays in this case were made within 20 hr. of the time of ejaculation. In considering the negative correlation which they obtained, these authors suggested that the removal of hyaluronidase from semen might improve the fertility of the semen. In this general connection it is interesting to note that Johnston and Mixner (3) found a first order partial correlation (limiting effect of sperm concentration) of -0.30 (significant at the 5 per cent level) between percentage of live spermatozoa in dairy bull semen and hyaluronidase concentration.