Individual fertility differences in the frozen‐thawed spermatozoa among semen donors in the Labrador Retriever

Abstract

Purpose We aimed to validate and determine the possible application of transcervical insemination of frozen semen for improved breeding in guide dogs for the blind in Japan.Methods From February 2004 to March 2007, a total of 53 Labrador Retriever bitches, used for the breeding of guide dogs for the blind, were transcervically inseminated with frozen-thawed semen from 13 males by means of a cystoscope. Results The overall whelping and pregnancy rate with the frozen semen was 42%. Pregnancy rates ranged widely from 0 to 100% depending on the semen donor male. Of 13 males, 6 males exhibited severely poor fertility (less than 20% pregnancy rate) and 3 males exhibited high fertility (over 70% pregnancy rate) on artificial insemination. However, the spermatozoa motility after thawing was not significantly different among these dogs. In addition, heterospermic insemination revealed the optimal timing for transcervical insemination with frozen-thawed semen to be by day 6 after the LH surge. Conclusions Although transcervical insemination of frozen-thawed semen is effective for breeding of guide dogs for the blind, some modification of freeze-thawing procedures might be required to overcome individual fertility differences in the frozen-thawed spermatozoa among semen donor dogs,. In addition, the motility of spermatozoa after thawing might not be an appropriate indicator of the relative fertility of frozen-thawed spermatozoa in dogs.

Fertilizing ability of canine spermatozoa cryopreserved with skim milk‐based extender in a retrospective study

“…Some of the TCIs were combined with natural mating to avoid the failure of conception of the bitches, as unsuccessful pregnancy of the bitches would considerably influence the production of guide dogs (Suwa et al., ). Natural mating with male dog which differed from donor of frozen semen was performed subsequent to TCI with cryopreserved semen.…”

“…The proportion of spermatozoa exhibiting a motility grade of +++ or ++ was used as the parameter for sperm motility. After examination of motility, the frozen‐thawed spermatozoa were subjected to artificial insemination (Suwa et al., ).…”

“…Inseminations were performed on standing and non‐sedated bitches. A catheter (8 Fr, Nippon Sherwood, Tokyo, Japan) equipped with a cystoscope for human use (Karl Storz, Germany) was inserted into the corpus uteri through the cervical canal (Suwa et al., ; Wilson, ), and 2 ml of semen (2 × 10 8 spermatozoa) derived from eight frozen‐thawed straws was inseminated through the catheter. Care was then taken to avoid backflow of the semen, so the catheter was withdrawn a few minutes after the insemination and the hind quarters of the bitch were kept elevated for 10 min.…”

“…Cryopreservation of canine spermatozoa provides an opportunity of genetic materials exchange and may lead to improvement of the breeding management programs used for working dogs. In particular, application of transcervical artificial insemination (TCI) using cryopreserved canine semen may contribute to adequate supply of guide dogs for the blind (Suwa, Abe, Lee, Ueta, & Suzuki, ).…”

Pronuclear formation of freeze-dried canine spermatozoa microinjected into mouse oocytes

“…Assisted Reproductive Technologies (ARTs) in canines, e.g. artificial insemination [18,19], in vitro fertilization [20,21] and somatic cell nuclear transfer [22,23], has been steadily progressing. ARTs seems to have led to the more efficient production of capable working dogs, and may be further advanced by successful preservation of canine spermatozoa.…”