Effect of the polyvinyl alcohol on the cryopreservation of ram spermatozoa

Abstract

The cryopreservation process causes lesions in the ram spermatozoids, for this reason, the extenders development including cryoprotectors that reduce the lesions is warranted. This report had as goal to evaluate the add on of polyvinyl alcohol in the compositions of an extender used to freeze semen. It was used 6 SRD rams, in a total of 30 ejaculates. The samples were conditioned at 5°C with tris glucose and, only after 1 hour, it was added 0,05% PVA. The spermatic motility was evaluated during 30 minutes, in periods of 2,5 minutes among each analysis. The motility comparison by the time was done through the variance analysis of Kruskal-Wallis.  The motility observed in 2,5 minutes after the PVA added was 70,5% , after this period the motility was decreasing. The maximum time of PVA exposition, before freeze, could be 5 minutes, where the motility was 46,5%. Therefore, it is possible to conclude that the exposition time of a spermatic cell in an extender with PVA in concentration of 0,05% cannot exceed 5 minutes, keeping this way the seminal quality before cryopreservation.