Malarmathi, MVadivoo, VSMuthuramalingam, TSenthil Kumar, TMAPalanisammi, ATANUVAS2019-11-132019-11-132016-07http://krishikosh.egranth.ac.in/handle/1/5810135223TNV_BL_2016_4(3)431-436Circulating Nucleic acids (CNAs) are extracellular or cell free nucleic acids which circulate in the bloodstream of healthy pregnant animals. The presence of CNAs in maternal plasma offers the non-invasive prenatal diagnoses of pregnancy associated disorders and also gives opportunities to detect prenatal sex using circulating fetal Y chromosome specific nucleic acid sequence. The present study was done to detect any significant difference in the level of CNAs in the plasma of pregnant (n=27) and non-pregnant (n=3) and recently calved (n= 11) Indian cross bred cows on different gestation stage. Plasma CNAs concentration ranged between 3 to 9.4 ng/μl in pregnant cows which was significantly higher (p<0.001) than non-pregnant cows (0.54 ng/μl). PCR amplification of SRY and AMEL gene were used to detect fetal sex using cfDNA. qRT-PCR assay was also used to confirm the presence of fetal RNA in the maternal blood based on SRY gene. PCR based prenatal fetal sex determination showed 80 per cent sensitivity, 100 per cent specificity and 88.89 percent accuracy, whereas qRT-PCR based assay showed 93.33 percent, 100 per cent and 96.29 per cent sensitivity, specificity and accuracy respectively.enVeterinary ScienceArticle