Repeated superovulation with a simplified FSH/eCG treatment for in vivo embryo production in sheep

F. FORCADA; AIT AMER MEZIANE, M.; ABECIA, J A; MAUREL, M.C.; J. A. CEBRIÁN-PEREZ; T. MUIÑO-BLANCO; ASENJO, B.; M.I. VÁZQUEZ; CASAO, A

THERIOGENOLOGY

ELSEVIER SCIENCE INC

Año: 2011

0093-691X

This study investigated the efficacy of a simplified repeated superovulation treatment (eCGplus FSH in a single dose, rather than the usual protocol of six decreasing doses of FSH) in the in vivoembryo production in Ojalada donor ewes during the breeding season. In vitro viability aftervitrification and warming of embryos recovered from both treatments was also assessed. In addition,the study examined the effects of the concentration of anti-eCG antibodies before each eCG/FSHtreatment on in vivo embryo production. Thirty-eight females at the end of their reproductive liveswere given the simplified superovulatory treatment up to three times at intervals of ≥50 d. The onsetof estrus was 5 h earlier (P<0.05) among ewes that received the eCG/FSH protocol (25.2 ± 0.80 h) thanit was among those that received the decreasing superovulatory treatment (30.1 ± 1.0 h), but the twotreatments did not differ significantly in ovulation rates or the number and viability of embryosrecovered. Both of the superovulatory protocols were significantly (P<0.05 to P<0.01) less effectiveafter the first application. After three superovulatory treatments, the average number of viableembryos per ewe was 14.1±2.3 and 13.7±2.5 in the decreasing and simplified protocols, respectively.High anti-eCG antibody concentrations just before the superovulatory treatment with eCG wereassociated with a significant decrease (P<0.05) in the rates of fertilization, viability, and freezability,especially in the second and third recoveries. Repeated superovulatory treatments with eCG/FSH canprovide an efficient means of producing high quality embryos in the ewes of endangered breeds at theend of their reproductive lives, although further studies are needed to characterize the responseassociated with high concentrations of anti-eCG antibodies.