The effect of the type of package, FlatPacks or straws, on cryopreservation of the jackass sperm-rich fraction

The effect of the type of package on the cryopreservation of jackass semen was studied, using the sperm-rich fraction of five jackasses and a special cryopreservation semen protocol, related to one extender and two different packages, FlatPacks or straws. The characteristics of the in vitro semen were evaluated after thawing. The motility results were 24.67% and 35.34% after thawing; 13.39% and 25.83% 60 minutes after thawing and 7.86% and 13.33%, 120 minutes after thawing. The vigor results were 2.55 and 3.33 after thawing, 1.57 and 2.48 60 minutes after thawing and 1.11 and 1.67 120 minutes after thawing, for FlatPacks or straws packages, respectively. The jackasses used were different regarding seminal characteristics, with great individual variation. The approved post-thaw viability (motility ≥ 30%, vigor ≥ 3) was affected by jackass and type of package, with the best results (P