Veterinary session

In recent decades, dog breeders have had a growing interest in artificial insemination with chilled semen. The use of chilled semen made it no longer necessary to transport animals for breeding, facilitating the international trade of genetic material. However, the shelf life of chilled sperm is limited, which is why reconciling the semen sampling with the fertilization date of the breeding bitch requires careful calculation.

Our research aims to assist practicing veterinarians in planning as well as to expand the knowledge about diluents that can be used to chill semen. In our studies, we tested the efficacy of five commercially available semen extenders in terms of how long they can maintain the motility of chilled (4-5 ° C) sperm, which is the most important and commonly used parameter to control normal sperm function and sperm quality.

The semen samples were obtained from 7 Beagle male dogs. The samples were analyzed and cooled in the Andrology and Assisted Reproduction Laboratory of the University of Veterinary Medicine. The extenders were added to the proportionally divided second sperm-rich fraction according to the instructions for use provided by the manufacturer. In our research, we tested the following extenders: AndroPRO® ChillGuard LT (MOFA Global, USA), AndroPRO® ChillGuard ST (MOFA Global, USA), Bovidyl® (Minitube, Germany), CaniPRO® ApX2 Chill 10 (MOFA Global, USA) és Triladyl® (Minitube, Germany).

Diluted samples were stored in a refrigerator at 5 ° C and analyzed for motility over six days.

The motility of diluted samples with mean progressive motility of 85 ± 3.43 decreased day by day. When using Bovidyl® (p = 0.0044) and Triladyl® (p = 0.0198) significantly lower motility levels were measured on the second day already. On day six, using all the extenders, a significant difference (AndroPRO® ChillGuard LT p = 0.0046, AndroPRO® ChillGuard ST p = 0.0107, CaniPRO® ApX2 Chill 10 p = 0.0142) was observed between the motility of fresh and diluted samples.

All diluents, except Bovidyl®, provided average progressive motility above 50% until the fifth day. The use of samples with progressive motility below 50% for vaginal artificial insemination is not recommended; instead, transcervical insemination is suggested. However, a very good pregnancy rate could be achieved by vaginal insemination of samples with progressive motility above 70%.

The CaniPRO® ApX2 Chill 10 extender proved to be the most effective in our studies. Using this extender we observed an average progressive motility above 70% until the fifth day.