Evaluation of stallion sperm

The conventional approach to evaluation of stallion semen dates back several decades ago and it should include: a gross evaluation of semen quality (colour and consistency), determination of semen pH, determination of the volume of gel-free semen, determination of sperm concentration, estimation of the percentage of sperm that are progressively motile, determination of the percentage of morphologically normal spermatozoa in the ejaculate and a longevity sperm motility study. Semen evaluation is very important to determine the stallion breeding potential as well as for the diagnosis of subfertility/infertility cases. However, most of the conventional parameters of stallion semen quality correlate poorly or not correlated with fertility. Given the limitation of estándar seminal parameters in predicting fertility or identifying subfertil stallions, other sperm tests have been added to conventional semen analysis and may be applied for stallion fertility evaluation and performed in referral centres as: Computer assisted sperm analysis (CASA) gives us a more objective and complete assessment of sperm motion characteristics, structural integrity of plasma membrane of the spermatozoa using traditional stains or fluorochromes, functional integrity of plasma membrane by means of HOST test, ADN integrity of spermatozoa through SCD test and specifical stains to asses acrosome estatus.