The effect of mare's age on multiple ovulation rate, embryo recovery, post-transfer pregnancy rate, and interovulatory interval in a commercial embryo transfer program in Argentina

MARINONE, ANA INÉS; LOSINNO, LUIS; FUMUSO ELIDA; RODRIGUEZ, E.M.; REDOLATTI, CECILIA; CANTATORE, SOFIA

ANIMAL REPRODUCTION SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 158 p. 53 - 59

0378-4320

Advanced maternal age is an important predisposing factor on the reduction of reproductive efficiency. The aim of this study was to evaluate the effect of donor?s age on several reproductive parameters in a commercial equine embryo transfer program. Donors were classified into 3 age groups: Group 1 = fillies (3 and 4 years old), Group 2 = middle age mares (aged5?10) and Group3 = oldmares (aged13?25). Embryo recovery,multiple ovulationand pregnancy rates and interovulatory intervals were compared amongst age groups. Group 1 (171/244, 70.1%) and Group 2 (774/1081, 71.6%) had a higher (P < 0.005) embryo recoveryrate than Group 3 (385/701, 54.9%). Groups 2 and 3 were 2.5 and 3.4 times more likely to have multiple ovulations than Group 1 (P < 0.05), respectively. The effect of age group on pregnancy rate was not significant (P > 0.05). The interovulatory intervals length was influenced by individual mare (P < 0.001), age (P < 0.04), Day of flushing (P = 0.009) and by month (P < 0.012). The overall mean interovulatory interval of Group 1 (16.4 ± 0.17 days) and Group 2 (16.6 ± 0.12 days) was not different (P > 0.05), but was shorter than the one of Group 3 (17.4 ± 0.15 days; P < 0.04). The embryo recovery rate of flushings from Groups 1 and 2 was influenced by the length of the previous interovulatory interval (P = 0.03).