Anotace:
The aim of the study was to determine the prevalence of selenium (Se) deficiency in Angus Aberdeen (AA) cows and calves during the grazing season on several farms in different geographical locations of the Czech Republic. Selenium deficiency was diagnosed by measuring Se concentrations in whole blood. A total of 78 cows and 78 calves aged 3 to 6 months were examined in eight herds. The reference range of blood Se in cows and calves is 80 to 120 ug/l. Lower values are indicative of deficiency. Overall, Se deficiency was observed in 39.75% cows and 80.76% calves. Suboptimal Se status was mainly a consequence of low Se concentration in pasture vegetation. The Se concentration in plants ranged from 0.032 to 0.086 mg/kg on dry matter basis. Selenium deficiency adversely affected fertility and natality in cattle. In the herd with the highest prevalence of Se deficiency (Herd 2), the number of calves reared till 6 months of age per 100 cows (natality) was as low as 80. The findings show that the grazing cattle suffered from major Se deficiency. The results of the study highlight the importance of implementing early diagnosis, effective prevention, and use of appropriate mineral supplements.