Effects of four different extenders and three different freezing rates on post-thaw viability of dog semen

Ejaculates were collected from 17 dogs. After initial evaluation the ejaculates were split into four equal aliquots and diluted with either Triladyl, Pipes, IMV Universal or Tris-fructose-citric acid extender, all containing egg yolk and glycerol. The extended semen was frozen in 0.5 ml straws at a slow, intermediate or fast freezing rate. After thawing, the percentage of progressively motile spermatozoa and the velocity of forward motion was evaluated. There was no difference between the extenders with regard to progressive motility. The slow, intermediate and fast freezing rates resulted in the highest, intermediate and lowest motility values, respectively, regardless of extender. All four extenders were equally suitable for freezing canine semen at a slow freezing rate.