Comparative Fertility of Freshly Collected vs Frozen–Thawed Semen with Laparoscopic Oviductal Artificial Insemination in Domestic Cats

Abstract

Artificial insemination (AI) is potentially invaluable as an adjunct to natural breeding for the conservation management of non-domestic felid populations. The efficacy of AI, however, must be substantially improved for applied use, especially when using frozen semen. Our recent advances in using laparoscopic oviductal AI (LO-AI) with low sperm numbers and freezing of cat semen in a soy lecithin-based cryoprotectant medium suggest that combining these two approaches might improve pregnancy outcomes with frozen-thawed spermatozoa. In this study, our objectives were to (i) assess the effect of two gonadotropin dosages (100 vs 150 IU eCG) on ovarian response in domestic cats and (ii) compare the relative fertility of frozen-thawed and fresh semen in vivo following LO-AI. All 16 females ovulated after gonadotropin treatment and were inseminated with fresh semen from one male and frozen-thawed semen from a second male. There were no differences between gonadotropin dosages in CL number, pregnancy percentage or litter size. Half (8/16) of the females conceived, with seven females giving birth to a total of 36 offspring. Paternity analysis showed that more kittens resulted from LO-AI with fresh (28/36, 78%) than frozen-thawed (8/36, 22%) semen, possibly due to impaired motility and longevity of thawed sperm. These results demonstrated that viable offspring can be produced by AI using semen frozen in a soy lecithin-based medium. Insemination with greater numbers of frozen-thawed spermatozoa, combined with further refinement of cat sperm cryopreservation methods, may be necessary to optimize pregnancy success with LO-AI in domestic and nondomestic cats.