Preselection of high and low ovulatory responders in sheep multiple ovulation and embryo transfer programs

• Published in: Theriogenology 2015-09, Vol.84 (5), p.784-790
• Main Authors: Bruno-Galarraga, M., Cueto, M., Gibbons, A., Pereyra-Bonnet, F., Subiabre, M., González-Bulnes, A.
• Format: Article
• Language: English
• Subjects: Animals; Chorionic Gonadotropin - pharmacology; Embryo recovery; Embryo Transfer - methods; Embryo Transfer - veterinary; Estrus Detection; Female; Follicle Stimulating Hormone - pharmacology; Follicular population; Multiple ovulation; Multiple ovulation and embryo transfer; Ovarian Follicle - drug effects; Ovary - drug effects; Ovulation - drug effects; Sheep - physiology; Superovulation
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/j.theriogenology.2015.05.011

The present study evaluated the feasibility of carrying out an easy-to-handle and cost-efficient test for the preselection of high– and low–ovulatory responder ewes under superovulatory protocols. The test was based on the assessment of the number of ovulations obtained in response to the administration of a single-shot eCG treatment. The predictive value of the test was determined by comparing the number of ovulations with yields obtained in response to a multiple-dose FSH treatment. In addition, the study determined possible effects of follicular status at first FSH dose and their relationship with subsequent ovarian response. A total of 31 Merino ewes received hormonal treatment comprising the administration of 800 IU of eCG at the end of progestative treatment. Twenty-three days later, multiple-dose FSH treatment (80-mg FSH, in six decreasing doses between Days 12 and 14 of a second progestative treatment) was applied to the same ewes. The study showed a significant relationship between the number of corpora lutea obtained in response to eCG treatment with respect to those obtained in response to FSH treatment (r = 0.791; P