Semen characteristics and testosterone profiles in ferrets kept in a long-day photoperiod, and the influence of hCG timing and sperm dilution medium on pregnancy rate after laparoscopic insemination

Abstract

Summary. Five domestic ferrets previously maintained for 12 weeks under a 16L:8D photoperiod were electroejaculated weekly for 15\p=n-\65weeks while continuing to be exposed to the prolonged light cycle. Two ferrets sustained spermatogenesis for 20 and 26 weeks, while sperm production in the remaining males either was sporadic or decreased, remained depressed and then increased to peak levels observed in other males. Regardless of the temporal spermatogenesis patterns within males, the number of electroejaculated spermatozoa with residual cytoplasmic droplets or abnormal acrosomes increased in all ferrets over time. Diluted ejaculates meeting artificial insemination criteria were deposited intravaginally or by transabdominal laparoscopy into the uterine horns of females treated 0 or 24 h earlier with 90 i.u. hCG. Vaginal insemination was ineffective (0 pregnancies in 10 attempts), but 17/24 ferrets (70\m=.\8%) inseminated laparoscopically became pregnant and delivered live young (mean litter size, 5\m=.\2kits). Number of motile spermatozoa deposited in utero (1\ m=. \ 6\ p=n-\ 10\ m=. \ 0 \m=x\ 106 cells), presence of glycerol in the sperm dilution medium (0 versus 4%) and time of hCG administration (0 versus 24 h before insemination) had no effect on pregnancy results or litter size.

Approaches and efficacy of artificial insemination in felids and mustelids

“…Most importantly and in contrast to our findings in felids, we determined that pre-ovulatory anesthesia in ferrets did not compromise ovulation and AI success [106]. High pregnancy rates (67-75%) were achieved in ferrets when anesthesia and insemination were conducted at either 24 h post-hCG ($6 h before anticipated ovulation) or the time of hCG administration ($30 h before ovulation).…”

“…3) was efficient. Seventeen of 24 ferrets (70.8%) inseminated in this fashion became pregnant and delivered live young (Table 2) [106]. Meanwhile, comparative assessments of 12 cryopreservation methods determined that a combination of an egg-yolk/lactose cryodiluent, the pellet freezing method and a 37 8C thawing temperature was effective for recovering maximal ferret sperm motility and acrosomal integrity.…”

“…With that baseline information, we began extensive studies in common (European) ferrets to develop a consistently effective approach for collecting and analyzing fresh or cryopreserved spermatozoa [106,107]. Ejaculates were collected to address the: (1) temporal spermatogenesis patterns and sperm viability; (2) comparative effectiveness of vaginal versus intrauterine insemination via a laparoscopic approach; (3) influence of sperm number and time of hCG administration on pregnancy success, gestation interval, and number of offspring produced; and (4) influence of cryodiluent, freezing method, and thawing temperature on biological competence of thawed ferret spermatozoa [106,107].…”

“…Ejaculates were collected to address the: (1) temporal spermatogenesis patterns and sperm viability; (2) comparative effectiveness of vaginal versus intrauterine insemination via a laparoscopic approach; (3) influence of sperm number and time of hCG administration on pregnancy success, gestation interval, and number of offspring produced; and (4) influence of cryodiluent, freezing method, and thawing temperature on biological competence of thawed ferret spermatozoa [106,107]. Such basic studies were crucial to developing reliable assisted breeding protocols.…”

“…Such basic studies were crucial to developing reliable assisted breeding protocols. For example, vaginal insemination was determined to be ineffective in the domestic ferret as none of 10 females became pregnant (Table 2) [106]. In contrast, transabdominal-intrauterine AI via laparoscopy (Fig.…”