Evaluation of Novel Hemato-Biochemical Biomarkers in Blood for Early Detection of Pregnancy and Estrus Cycle Stages in Female Ruminants

This study analyzes newly introduced oxidative and hematobiochemical indices of blood as possible indicators of pregnancy, estrus, and early loss of the embryo of female ruminants. Out of the 60 examined, animals were classified in four groups as confirmed pregnancy, estrus, diestrus non-pregnant, and early loss of the embryo. Blood samples were taken and tested for hematological parameters, some metabolic hormones, several biochemical factors, and indices of oxidative stress, as well as markers of acute phase proteins. Pregnant animals showed significantly higher levels of progesterone (P < 0.001), leptin (P < 0.01), and total proteins (P < 0.05). Participants of the estrus phase showed large levels of estradiol (P < 0.001), glucose (P < 0.01), and RBC count (P < 0.05). For oxidative stress, the profiles of pregnant groups showed lower levels of MDA (P < 0.001), and of the enzymes SOD and catalase, higher than the estrus and embryonic loss phase groups, and thus demonstrated significantly greater antioxidant activity (P < 0.01). Prior to an early loss of the embryo, the concentration of haptoglobin and ceruloplasmin were significantly increased (P < 0.01), while the concentration of progesterone was significantly decreased (P < 0.001). Early pregnancy was predicted with 89% accuracy from the multivariate regression where a biomarker panel made of progesterone, leptin, MDA, and haptoglobin was identified. The combination of progesterone and MDA was shown from the AUC to have the highest diagnostic power (0.93) and with that, an ROC was created. These strong results strongly suggest that a low-cost diagnostic approach to reproductive management in ruminants could be developed.