The objective of the present work was to evaluate the efficiency of ethylene glycol on criopreservation of canine semen, considering its possible deleterious effects upon semen motility, vigor and morphology at the pre and post freezing stages, using a tris-egg yolk extender. Four adult german shepards were used as donors. Samples were obtained by digital manipulation, and only ejaculates presenting a minimum of 90% motility and 5 (0-5) vigor and no more than 35% of total morphological defects were considered. Ethylene glycol concentrations tested were 0.25, 0.50 and 1.0M and 0.80M glycerol served as control. Motility and vigor were evaluated in the rich fraction, after first and second dilution, after 1 hour of stabilization at 4ºC and after thawing. Sperm morphology was examined in the fresh sample and after thawing in each of the treatments. There were no detectable differences among the groups in sperm motility and morphology after thawing. There were no differences in vigor among the 0.25, 0.50M ethylene glycol and the 0.8M glycerol, but the 1M ethylene glycol had lower vigor scores after thawing. We conclude that ethylene glycol can be used as a cryoprotectant in the concentration of 0.25, 0.50 and 1.0M instead of glycerol.
semen; dog; freezen; ethylene glycol
