ABSTRACT
Recovering and storing sperm from the epididymides of males of rare felidae is useful for preserving the species. The objective of the present study was to determine pregnancy rates following artificial insemination (AI) of frozen-thawed epididymal sperm, which were cryopreserved following low-temperature storage of the epididymides. In this study, these sperm were used for unilateral intrauterine AI (UIUAI) or unilateral intratubal AI (UITAI) using 40 × 10(6) and 10 × 10(6) sperm, respectively. The caudal epididymides of 17 cats were stored at 4 °C for 24 h after castration. Artificial insemination of seven female cats was performed on Days 3 or 4 (start of estrus = Day 1) by UIUAI, 20 h after injection of 100 IU hCG to induce ovulation. Furthermore, UITAI at 24 h (UITAI-24) or 30 h (UITAI-30) after hCG were also done (five cats per group). It was noteworthy that AI by UIUAI and UITAI-24 was performed before ovulation, whereas AI by UITAI-30 was performed after ovulation. Pregnancy rates were 28.6% (2/7) by UIUAI, 80% (4/5) by UITAI-24, and 20% (1/5) by UITAI-30. Litter size was one or two by UIUAI, and one to four by UITAI. Spontaneous abortion occurred on Days 25-30 of pregnancy in one of the two female cats pregnant following UIUAI, and in two of five female cats pregnant following UITAI. Based on the high pregnancy rate obtained with 10 × 10(6) sperm in the UITAI-24 group (AI performed before ovulation), we concluded that this was the most appropriate method for AI with frozen-thawed epididymal sperm after initial low-temperature storage of epididymides.
Subject(s)
Cryopreservation/veterinary , Epididymis/cytology , Insemination, Artificial/veterinary , Spermatozoa , Animals , Cats , Conservation of Natural Resources , Cryopreservation/methods , Endangered Species , Felidae/physiology , Female , Male , Ovulation Induction/veterinary , Pregnancy , Pregnancy Rate , Semen Analysis/veterinaryABSTRACT
We observed the influences of low-temperature storage of the feline epididymis on the epididymal semen qualities before and after cryopreservation to identify the optimal duration for low-temperature storage of the epididymis. After excision, the feline epididymis was stored at 4 degrees C for 0-72 hr and then subjected to epididymal sperm collection. When sperm from the refrigerated cauda epididymis were frozen and thawed, there was no significant difference in sperm motility between the 0- and 24-hr low-temperature storage groups, but sperm motility was significantly decreased in the 48-hr storage group. The above findings suggested that low-temperature storage of the epididymis until 24 hr is useful for frozen sperm collected from the feline cauda epididymis.
