Detection of damage in mammalian sperm cells.

Fertility evaluation of frozen/thawed semen

In vitro evaluation of sperm quality.

Seasonal changes in semen quality and freezability in the Warmblood stallion

Establishment of pregnancies after serial dilution or direct transfer by vitrified equine embryos.

The hypo-osmotic test has been used successfully on equine semen and was considered to be a simple and accessible method which could be a useful addition to routine equine semen analysis. It was therefore of interest to determine whether the hypo-osmotic test is significantly correlated to proposed criteria of fertility. The stallions were divided into two groups on the basis of threshold levels of fertility. A significant difference (P<0.05) was found between the two groups for the following parameters: progressive motility, morphologically normal spermatozoa, percentage of swelling with the hypo-osmotic test, percentage of pregnant mares and number of services per pregnancy. The hypo-osmotic test provided a simple evaluation of membrane function and the results obtained show stallions with low swelling scores (<40%) to be of doubtful fertility. The hypo-osmotic test was not correlated with percentage of pregnant mares but showed a tendency to correlate with the number of services per pregnancy, therefore it could be an additional method for evaluating stallion fertility. Further studies are needed to confirm this observation.

E.P. Gonzalez

Papers

The HOS test and its relationship to fertility in the stallion.

Cryopreservation of equine embryos by two vitrification methods