Results of 527 controlled artificial inseminations in dogs

During 1990 and 1991, 527 artificial insemination (AI) procedures were performed by 40 veterinarians, under the Swedish Kennel Club control scheme, and reported to the Kennel Club within 14 days. The most common reason for AI (37.2%) was import of fresh and frozen semen or quarantine, i.e. introduction of new genetic material. Fresh semen (468 AIs) was deposited into the cranial vagina, and frozen semen (59 AIs) was inseminated transcervically into the uterus. Pregnancy rates were 54.7% with fresh and 39.0% with frozen semen. When corrected for stage of oestrus at the time of AI and semen quality, the pregnancy rates were 62.3 and 51.1%, respectively. Bitches inseminated with frozen semen had a 29.7% lower pregnancy rate and 30.5% smaller litter size than bitches receiving fresh semen; these differences were statistically significant. Forty-four bitches (8.4%) were also mated. Their pregnancy rate was significantly higher (88.6%; 90.7% corrected) than that of bitches inseminated with fresh semen only. Pregnancy rate was significantly higher in bitches inseminated twice with fresh semen than in those inseminated once only. Litter size and gestation length increased with the number of AIs. Most bitches whelped 62 days after a single AI with fresh or frozen semen, but the gestation period varied between 55 and 69 days. There were significant differences in fertility between breeds. Pup deaths occurred in 33.8% of the litters and the pup death rate during the first 3 weeks of life was 11.6%. The number of pups resulting from AI amounted to 1.1% of the total number of pups registered with the Swedish Kennel Club.