An association between abortion and low selenium (Se) status in cattle has been suspected, but not confirmed previously. Abortion outbreaks in 3 Se-deficient beef cattle herds, between 2010 and 2013, are described. In total, 130 out of the 480 cattle aborted (27.1%): among these, 28/130 (21.5%) abortions were in herd 1, 47/150 (31.3%) in herd 2 and 55/200 (27.5%) in herd 3. Five aborted fetuses were examined grossly and histopathologically. Laboratory examinations for bacterial, viral and parasitic causes of abortions were conducted (fetuses, fetal membranes, cows’ blood) and were found negative. Moreover, blood samples from 18 aborting cows were examined for Se, vitamin A and vitamin E concentrations. Blood Se levels in cows belonging to farms that experienced abortions were lower than reference values and significantly lower than 28 control cows from 3 herds without abortions (0.46±0.08 vs. 2.20±0.04 μmol/L; P<0.0001). Serum vitamin E and vitamin A concentrations were within reference range and did not differ from controls. Skeletal muscle and myocardial degeneration and atrophy were observed in 5 aborted calves. Abortions were significantly reduced from 26% to 1.1% following the subcutaneous administration of a Se and vitamin E containing commercial preparation to each of the remaining pregnant cows, at a dose 0.1 mg/kg body weight for Se and 8.98 mg/kg body weight for vitamin E. In conclusion, determination of whole blood Se status before late gestation is useful in early diagnosis of Se deficiency and should be included in the diagnostic panel when investigating abortions in cattle.

Key words: Abortions, Beef cattle, Prevention, Selenium deficiency