Birth of puppies after endoscopically guided transcervical intrauterine insemination with cryopreserved epididymal canine spermatozoa.

Abstract

Background: The preservation of epididymal spermatozoa is useful for saving important genetic material from valuable individuals who die suddenly or have to be castrated. The birth of puppies after artificial insemination with canine epididymal spermatozoa has been reported in only a few cases. Surgical insemination with frozen-thawed epididymal spermatozoa has resulted in pregnancies, but usually with low conception rates. Freshly collected and chilled epididymal canine semen has also resulted in conception after vaginal insemination. Considering the invasiveness of surgical insemination and the almost unlimited storage time of cryopreserved spermatozoa, transcervical intrauterine insemination with frozen-thawed epididymal spermatozoa would be beneficial. It has the potential to use genetic material that would otherwise be lost, both in domestic dogs and for the preservation of wild threatened canids.

Case presentation: A 7-year-old, 20 kg male hunting dog was injured by a wild boar during hunting, and euthanasia was recommended for welfare reasons. Because the dog was a hunting champion in a numerically very small breed, the owner wanted to have spermatozoa preserved for future breeding. The dog was anaesthetised, both testes were removed, and the dog was thereafter euthanized. Spermatozoa from both caudae epididymides were released in a prewarmed Uppsala extender with the mincing method. The samples were routinely frozen with the Uppsala method. A half-filled straw was used for test thawing, resulting in 20% motile spermatozoa with slow progressive movement. Three years later, a 23-month-old bitch of the same breed was inseminated with endoscopically guided transcervical intrauterine sperm deposition. She was inseminated once, five days after a serum progesterone value of 6.9 nmol/mL was reached, and two days after a value of 24.8 nmol/mL was reached. The total amount of cryopreserved spermatozoa was used (a total dose of 1087 × 10⁶ spermatozoa and 217 × 10⁶ progressively motile spermatozoa remaining after test thawing). Eight puppies were born 59 days after insemination.

Conclusions: Although rarely reported, artificial insemination with cryopreserved epididymal canine spermatozoa is an alternative in preserving valuable genetic animals when a male is injured beyond recovery.