The effect of pre-ovulatory anaesthesia on ovulation in laparoscopically inseminated domestic cats

Abstract

Laparoscopic intrauterine artificial insemination (AI) of electroejaculated spermatozoa was used to compare embryo development and conception rates in domestic cats inseminated either before or after ovulation. Females were given a single (100 iu) injection of pregnant mares' serum gonadotrophin (PMSG) followed by either 75 or 100 iu human chorionic gonadotrophin (hCG) 80 h later. Cats were anaesthetized (injectable ketamine HCl/acepromazine plus gaseous halothane) 25-50 h after administration of hCG for laparoscopic assessment of ovarian activity and for transabdominal AI into the proximal aspect of the uterine lumen. At the time of AI, 23 cats were pre-ovulatory (25-33 h after hCG injection) and 30 were post-ovulatory (31-50 h after hCG injection). Pre-ovulatory females produced 10.5 +/- 1.1 follicles and no corpora lutea compared with 1.9 +/- 0.5 follicles and 7.5 +/- 0.9 corpora lutea for the post-ovulatory group (P < 0.05). Six days later, the ovaries of nine pre-ovulatory and 12 post-ovulatory females were re-examined and the reproductive tracts flushed. On this day, pre-ovulatory cats produced fewer corpora lutea (2.8 +/- 1.5; P < 0.05) and embryos (0.4 +/- 0.3; P < 0.05) than post-ovulatory females (18.9 +/- 3.3 corpora lutea; 4.6 +/- 1.2 embryos). Two of the 14 cats (14.3%) inseminated before ovulation and not flushed became pregnant compared with 9 of 18 cats (50.0%) inseminated after ovulation and up to 41 h after hCG injection (P < 0.05). These results indicate that ovulation in cats is compromised by pre-ovulatory ketamine HCl/acepromazine/halothane or laparoscopy or by both and that electroejaculated spermatozoa deposited by laparoscopy in utero, after ovulation, result in a relatively high incidence of pregnancy. Because ovulation usually occurs 25-27 h after injection of hCG, the lifespan for fertilization of the ovulated ovum appears to be at least 14 h in vivo in cats.

Approaches and efficacy of artificial insemination in felids and mustelids

“…This transabdominal approach involved inserting a laparoscope through a cannula device (and a 3 cm skin/muscle opening) in the abdominal wall, followed by catheterizing the uterine lumen and depositing sperm in the cranial aspect of the uterine horn (Fig. 3) [63]. Laparoscopy also has been used extensively for characterizing felid reproductive tract anatomy and ovarian events, including documenting follicular development, presence of fresh (corpora hemorrhagica, CH) and mature corpora lutea (CL) and the effectiveness of various gonadotropin therapies [9,10].…”

“…Laparoscopy also has been used extensively for characterizing felid reproductive tract anatomy and ovarian events, including documenting follicular development, presence of fresh (corpora hemorrhagica, CH) and mature corpora lutea (CL) and the effectiveness of various gonadotropin therapies [9,10]. This laparoscopic AI technique was utilized initially in the domestic cat and then successfully extrapolated to the cheetah (Table 2) [34,63].…”

“…However, studies from our laboratory revealed that the use of anesthesia prior to ovulation (to allow animal handling) compromises ovum release and subsequent pregnancy establishment in felids. When domestic cats are treated with eCG/hCG and anesthetized with ketamine hydrochloride, acepromazine and gaseous halothane immediately before ovulation, only a few females ovulate, and pregnancy success after AI is low (14%; Table 3) [63]. Conversely, when the interval from hCG administration-to-anesthesia is increased to 6-14 h after the anticipated time of ovulation, all cats release ova, and 50% of these become pregnant and deliver live offspring (Table 3) [63].…”

“…When domestic cats are treated with eCG/hCG and anesthetized with ketamine hydrochloride, acepromazine and gaseous halothane immediately before ovulation, only a few females ovulate, and pregnancy success after AI is low (14%; Table 3) [63]. Conversely, when the interval from hCG administration-to-anesthesia is increased to 6-14 h after the anticipated time of ovulation, all cats release ova, and 50% of these become pregnant and deliver live offspring (Table 3) [63]. Tsutsui et al [66] found conflicting results.…”

“…For three decades, laparoscopic viewing of felid ovaries has allowed documenting follicular development and ovulation in non-gonadotropin-treated cycles [75], as well as the timing and impacts after various hormonal therapies [9,72,76]. This has included tracking and photographing the fate of immature and mature follicles, fresh (CH) and mature (CL) ovulation sites over time [63].…”