Measurements of the ‘motility’ of bull sperm cells under various conditions

Abstract

In this paper the results are described of experiments on bull sperm cells with the photo-electric device for measuring the ‘motility’, as developed by Rikmenspoel, van Herpen & van Dam (1956).It was found that the velocity distribution of sperm samples differs only slightly from a Gaussian one. The form of the distribution curve, which is a bit skew, is rather constant between ejaculates. This means that generally the ‘motility’ of a sperm sample can be characterized by the mean velocity of the sperms, the standard deviation of the velocity distribution and the number of cells moving normally. The mean ratio of velocity and frequency of rotation (the ‘speed’ of the screwing movement of the head of the sperm cell) was found to be a less important motility characteristic for most experiments.The scattering of the above-mentioned properties in various ejaculates were measured, while the sperm samples were all kept in the same conditions. It was found that the mean velocity has a rather constant value.A linear relationship between the mean velocity of the sperms of a sample and the viscosity of the diluent is found. This holds also for the dependence of the ‘speed’ of the head movement and the viscosity.The mean velocity of sperm cells was found to increase approximately in a straight-line relationship with the temperature in the range 33–41° C. There were indications that the mean velocity may reach a maximum in the region of 42–45° C.If sperm samples are stored at 4° C, the mean velocity and the number of cells moving normally is found to decrease exponentially. The decrease of the number of cells moving normally is three to four times faster than that of the mean velocity. Some evidence was obtained that the characteristic time for the decrease of the number of cells moving normally is bull-specific.