General principles of semen evaluation

Laboratory-based evaluations of stallion breeding potential have been conducted for many decades, but the results of such evaluations do not have an exact correlation with actual fertility. The reasons for this disparity are varied, but mare and management factors can certainly confound one’s interpretation of the actual intrinsic fertility of a stallion. In other instances, the fertility cannot be explained by standard tests of semen quality. As an example, we conducted a fertility trial with a subfertile stallion whose semen was subjected to density-gradient centrifugation in an effort to improve semen quality prior to insemination. Values for sperm motility before and after semen processing ...