Quantification of Bovine Sperm Separation by a Swim‐up Method Relationship to Sperm Motility, Integrity of Acrosomes, Sperm Migration in Polyacrylamide Gel and Fertility

Abstract

The number of bovine spermatozoa separated in a swim‐up procedure was quantified using an electronic cell counter. In an initial test of the swim‐up procedure, non‐frozen sperm samples with different ratios of live to dead cells were prepared and tested for the number of spermatozoa counted by the swim‐up procedure. In ejaculates from six bulls, the number of spermatozoa swimming up was related to the number of live cells present (R2=0.97). Next, sperm quality of frozen‐thawed semen immediately after thawing was measured at 37 C by swim‐up sperm count, sperm motility, spermatozoa with an intact acrosome and migration in Polyacrylamide gel and then compared with the fertility of the semen used for artificial insemination. Twenty‐nine ejaculates of frozen‐thawed semen from 11 bulls were evaluated. Correlations with fertility were highest on an ejaculate basis for motility (r = 0.41, P = 0.05) and for swim‐up sperm count (r = 0.35, P = 0.06). On a bull basis, swim‐up sperm count had the highest correlation with fertility (r = 0.59, P = 0.06). In a multiple regression model to predict male fertility that included all described measures of semen quality, a R2 value of 0.69 was obtained. This is the first report showing that the ability of spermatozoa to swim out of a more dense medium (whole milk‐glycerol extender) into culture media is quantitatively related to in vivo fertility. 1987 American Society of Andrology