Influence of day of oestrus on egg viability and comparative efficiency of in vitro fertilization in domestic cats in natural or gonadotrophin-induced oestrus.
Thirty-six domestic cats received 100 iu hCG (i.m.) on day 1, 2 or 3 of a natural, behavioural oestrus. Twenty-two anoestrous cats were injected with 150 iu pregnant mares' serum gonadotrophin (PMSG; i.m.) followed 84 h later by 100 iu hCG. Twenty-four to 26 h after hCG, all cats were examined laparoscopically to determine the number of ovarian follicles and to recover follicular eggs. Mature eggs were cultured with conspecific spermatozoa and examined 30 h later for cleavage. Within the natural oestrus group, cats on day 1 produced fewer (P < 0.05) follicles and total eggs than females on day 2 or 3, and 88.9% of the day 1 eggs were degenerate or immature and unsuitable for in vitro fertilization (IVF). Although only 54.5% of the cats in the PMSG/hCG group exhibited overt oestrus, mean (+/- SEM) numbers of follicles (9.7 +/- 0.8) and oocytes recovered (8.7 +/- 0.8) were at least twofold greater (P < 0.001) than those measured in the natural oestrus group (3.7 +/- 0.6; 3.4 +/- 0.6, respectively) or subgroups on day 2 (3.7 +/- 0.4; 3.3 +/- 0.4) and day 3 (5.7 +/- 0.8; 5.3 +/- 0.8). Overall, the proportion of eggs cleaving in vitro was similar (P > 0.05) between the natural oestrus group (48.3%) and the PMSG/hCG group (50.9%), but the latter group produced more than twice the number of embryos per donor. Embryo quality was unaffected (P > 0.05) by day of hormone treatment, and more than 80% of all two-cell embryos were rated good-to-excellent quality.(ABSTRACT TRUNCATED AT 250 WORDS)
Donoghue
A M
AM
National Zoological Park, Smithsonian Institution, Washington, DC 20008.
Johnston
L A
LA
Goodrowe
K L
KL
O'Brien
S J
SJ
Wildt
D E
DE
D000818:Animals; D002415:Cats; D002470:Cell Survival; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D004971:Estrus / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006064:Gonadotropins, Equine / Q000494:pharmacology; D009865:Oocytes / Q000166:cytology*; D009866:Oogenesis / Q000187:drug effects; D013997:Time Factors
D006063:Chorionic Gonadotropin; D006064:Gonadotropins, Equine