Comparative study of different methods for dog semen cryopreservation and testing under clinical conditions

The extenders and freezing rates from three different freezing protocols we re combined and compared to each other in order to study the post-thawing a crosome integrity and fertility of frozen dog sperm. A commercial bovine TR IS-base extender (TRILADYL) and two self-made canine semen extenders (Norwe gian and Dutch) were combined with a conventional bovine and two canine fre ezing regimes, and acrosome integrity of frozen/thawed spermatozoa was asse ssed by fluorescein isothiocyanate conjugated peanut agglutinin staining (F ITC-PNA). Differences between freezing/thawing protocols were reflected in the proportion of cells with acrosomal damage and not based on motility res ults. It was concluded that during dog semen cryopreservation extenders had less influence on the post-thawing sperm quality than did the freezing rat es. The optimal extender/freezing rate combination (TRILADYL/Norwegian) was used in the clinical practice to evaluate the fertility of frozen sperm ad ministered by intrauterine insemination using a surgical approach. The preg nancy rate was 57% (4/7), but the average litter size was low (2.8). This m ay have been due to the insufficient sperm numbers contained in an insemina tion dose and/or to the incorrect timing of artificial insemination (AI). T he final conclusion is that the commercial bovine extender is useful for fr eezing dog semen, and the TRILADYL/Norwegian freezing protocol is recommend ed as the most advantageous combination for the freezing of canine semen in the clinical practice.