A correlation between a spectrophotometric quantitation of rabbit spermatozoan motility and velocity

Rabbit sperm motility was measured spectrophotometrically and a sperm motility index (SMI) was obtained. A comparative analysis between the SMI values and the velocity of motile sperm (obtained by time lapse photography of sperm tracks) was performed. The SMI specifically was compared to the mean velocity of the first 300 sperm cells observed and to the mean velocity of just the first 300 progressively motile sperm cells. In both comparisons, the SMI was highly correlated to the sperm track length (sperm velocity). In addition, a modification of the spectrophotometric procedure is described which allows measurements of the SMI to be made on semen extended into egg-yolk glycerine cryopreservation agents.