Effect of Equex STM on the quality of frozen-thawed dog semen

The aim of the study was to estimate the effect of Equex STM on some spermatozoa properties in cryopreserved dog semen. The study was carried out on 94 ejaculates collected from 25 stud dogs, aged 2-7 years. Each sperm-rich fraction of ejaculates was divided into two samples: experimental and control. Experimental samples were diluted in Tris-citric acid-glucose extender with 1% addition of surfactant Equex STM (active ingredient - SDS sodium dodecyl sulphate). Control samples were diluted in the same extender, but without adding the surfactant. The extended, cooled and equilibrated semen was frozen in 0,5 ml Cassou straws in liquid nitrogen vapors at -140degreesC for 10 minutes. The straws were thawed in a water bath at 70degreesC for 6 seconds. The percentage of progressive motile spermatozoa and GOT activity in extracellular fluid were significantly different in experimental and control samples after equilibration, as well as after thawing. Motility was higher and GOT activity was lower in the experimental samples. It was proved that adding a surfactant to the extender improves the post-thaw longevity of dog spermatozoa incubated at 22degreesC. The results of the investigation suggest that Equex STM exerts a beneficial effect on spermatozoa structure, metabolism and, in particular, on midpiece membrane integrity in cryopreserved dog semen. Prolonging spermatozoal longevity after thawing could improve the results of artificial insemination of bitches with frozen-thawed dog semen.