Parent-of-origin effects for the number of oocytes and embryos in Gir cattle

Imprinting is a phenomenon that alters the expression of genes according to the parental origin of their alleles. A quantitative form to evaluate the imprinting effect is known as parent-of-origin effect. Our aim with this work is to identify parent-of-origin effects that influence the number of oocytes and embryos in Gir dairy cattle. A dataset with 17,526 Ovum Pick Up observations from 1641 Gir donors was used to estimate parent-of-origin effects for the traits number of total oocytes (TO), number of viable oocytes (VO) and number of embryos (EM). To identify parent-of-origin effects, dam and sire gametic effects were included, individually or together, in an animal model for TO, VO and EM traits. For TO, inclusion of paternal origin effects in the model was significant (P < 0.05), and explained 6 % of the total phenotypic variance. For VO and EM no significant parent-of-origin effects were found for either parental line. In conclusion, paternal effects appear to influence the total oocyte production in the Gir cattle breed.