Evaluation of some metabolic and pathophysiologic causes of abortion and stillbirth in an Isfahan dairy farm

Abortion and stillbirth are the effective reproductive factors that affect dairy farm profitability. The present study was designed to investigate some metabolic and pathophysiologic factors affecting abortion and stillbirth in Holstein dairy cows. Samples were collected from 43 Holstein dairy cows. Five early postpartum cows were used as stillbirth control group and five of 5 to 7-month-pregnant cows with no history of abortion were enrolled as abortion control group. Then differential blood cell counting, measurement of thyroid hormones concentrations and activities of hepatic enzymes including SGOT and SGPT were assayed on cows blood samples. In addition, microbial culturing of abomasum contents, ELISA test on brain tissue and ventricular fluid, measurement of liver glycogen concentration and histological evaluation of liver were performed on the dead calves. The results showed that the T3 to T4 ratio decreased in each group in comparison with their own controls (P<0.01). Furthermore, SGOT and SGPT activities in the plasma of both abortion and stillbirth groups were lower than their respective control groups (P<0.01). The highest neutrophils to lymphocytes ratio were observed in cows with dead born calves (P<0.001). Also, the hematocrit percent, RBC count and hemoglobin concentration increased in stillbirth cows compared with their control group (P<0.001). Liver consistency was better in aborted calves than stillborn ones, but liver glycogen concentration in dead born calves was higher (P<0.05). Microbial analysis showed that the 20.12% of aborted or dead born calves had bovine virus diarrhea in their brain tissue, but antibody titration of Neospora was not positive in any calves. The present results indicated that decreases in T3 to T4 ratio and SGOT and SGPT activities in the plasma of pregnant cows may be appropriate to evaluate the possibility of abortion or stillbirth. It seems that the presence of infectious agents has still a main role in the incidence of abortion and stillbirth, so diseases control by increasing the hygiene level and continues vaccination is so necessary.