Determination of expression patterns of miR-26a, and preimplantation factor levels for early pregnancy detection in nulliparous and multiparous cows.

For maximum productivity in a dairy farm, the earliest and the most accurate detection of pregnancy is essential. The aim of this study was to determine the efficacy of expression patterns of miR-26a, and serum Preimplantation Factor (PIF) levels for pregnancy diagnosis during the early pregnancy in nulliparous and multiparous cows. A total of 60 cows (30 nulliparous and 30 multiparous Holstein cows) were enrolled in the study. Blood samples were collected for miR-26a on days 8 and 16 (D8 and D16), and for the PIF on days 10 and 20 (D10 and D20) following insemination (D0). Pregnancies were determined by ultrasonography on the 28th day after insemination. Expression levels of miR-26a determined by qPCR. PIF levels were assessed by using commercial ELISA kits. All data were analyzed by using the MIXED procedure of SPSS. The expression levels of miR-26a were 6.64 folds higher on D16 in pregnant compared to non-pregnant multiparous cows (p < .05). On D8 and D16, miR-26a expression levels were found higher 13 folds in pregnant compared to non-pregnant nulliparous cows (p < .05). Additionally, miR-26a expressions were higher 5.42 folds (p < .05) on D8, 7.19 folds higher (p < .01) on D16 in pregnant nulliparous and multiparous cows, and were 6.30 folds higher (p < .001) on D8 and D16 according to non-pregnant animals. PIF levels were greater in pregnant animals (p < .05). Analyzing miR-26a on D8 might be considered as sufficient in nulliparous cows. Pregnancy detection in multiparous cows can be made on the 16th day with this method. Furthermore, PIF evaluations may be sufficient on D10 in multiparous cows. Besides, PIF levels and miR-26a expression levels might be used safely in field conditions and clinical applications.