In Vitro and In Vivo Efficiency of Extenders Added to Thawed Stallion Semen.

BACKGROUND

Addition of extenders to thawed semen could improve fertility.

OBJECTIVE

To determine the efficiency of extenders to increase viability of thawed semen, measured by sperm parameters in vitro and pregnancy rates after artificial insemination (AI).

MATERIALS AND

METHODS

Sperm motility and acrosin activity were measured during a thermoresistance test (TRT).

RESULTS

Progressive motility decreased (P<0.05) after 30 min in thawing semen treated with saline solution (SS) and only after 60 min with Tyrode's solution (TS) or freezing diluent (FD). The total motility decreased (P<0.05) after 60 min in thawed semen treated with SS, and after 90 min in thawed semen containing TS or FD. The acrosin activity decreased (P<0.05) after 60 min during the TRT, but there was no difference among treatments throughout the TRT. The pregnancy rates were similar among thawed-semen supplemented with SS, TS or FD.

CONCLUSION

The extenders neither improve sperm parameters nor enhance AI results.