RESUMEN
A mixture of bovine DNA from a male and a female Jersey (Bos taurus taurus) bred in different proportions was used to determine the sensitivity of PCR to amplify and discriminate the bovine DNA samples. Samples were obtained from the peripheral blood of a bull and a heifer and DNA was isolated using a commercial kit for extraction and purification of nucleic acids. Two primers sets were designed to flank genomic regions: one autosomal and one Y-specific. DNA samples were diluted in water to a final concentration of 4x10-14 ng. The results showed positive amplification of the samples diluted to a concentration of 4x10-10ng and 4x10-4ng for the autosomal and Y-specific regions, respectively. PCR was able to discriminate the male DNA in a mixture of 99:1 (DNA ♀: DNA ♂) heifer to bull ratio. Therefore, the PCR was successful in amplifying the bovine genome in samples containing low concentrations of DNA. Thus, PCR can be used as a sensitive and efficient tool to determine the sex of the fetus in pregnant cows, helping to promote correct and efficient animal management, sex selection, and breeding in commercial herds.