Prediction of fetal sex in the ovine species could be useful in the management decisions, such as sex selection in breeding programs, culling decisions, and lowering the progeny test cost. In the present study detection of fetal SRY gene in maternal blood plasma using the polymerase chain reaction technique was used to predict fetal sex at different times of gestation in the ewe. The quantitative changes of fetal DNA during pregnancy were also investigated using quantitative real-time polymerase chain reaction. Fetal DNA was isolated from blood plasma of 46 pregnant ewes during the second to fifth month of gestation. The 286-base pair DNA fragment was detected in all samples with male pregnancies, but no female pregnancies. The sensitivity and specificity of tests were 100% with no false negative or false positive results. It was also determined that fetal DNA levels are significantly increased during pregnancy, up to approximately 1.65-fold in the last 2 months of pregnancy. This is the first report of fetal sex determination and circulating fetal DNA quantification by a molecular method in the ovine species

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