Abstract
ABSTRACT. Lopes E. de P., Pinho R.O., Siqueira J.B., Rocha A.N., Pereira J.V.T. do N., Martins L.F., de Freitas B.W. & Guimarães J.D. [Correlation of factors which affect reproductive eficiency of Mangalarga Marchador mares in embryo transfer programs]. Correlação dos fatores que interferem na eficiência reprodutiva de éguas Mangalarga Marchador em programas de transferência de embriões. Revista Brasileira de Medicina Veterinária, 35(1):69-75, 2013. Departamento de Medicina Veterinária, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Campus Universitário, Viçosa, MG 36570-000, Brasil. E-mail: jhonatavet@yahoo.com.br The objective of this study was to verify the relationship of some reproductive features with embryo recovery in donor mares and recipients reproductive in embryo transfer programs. There were used 209 Mangalarga Marchador mares from five to 20 years of age, accompanied during six reproductive seasons, evaluating some reproductive features such as foal heat, embryo age, synchrony between donor and recipient mares, among others. There were 1,140 flushing procedures with 72.8% of recovery rate. Significant correlation was observed only in embryo recovery with the size of the first follicle (r = 0.08) and with artificial insemination of the donor in pre-ovulatory phase (r = 0.11), beyond the mares status with synchrony between donor and recipient (r = 0.06), although the correlation values have been very low. The low correlations obtained between the studied features have small influence over pregnancy rates in an equine embryo transfer program. The adoption of a higher flexibilization in the ovulatory synchronism between donor and recipient mares optimizes the use of recipient mares, thus reducing costs and facilitating management of horse breeding farms.