Selenium concentration in blood and hair of holstein dairy cows.

Four-hundred Holstein cows in 40 dairy farms in north Greece were included in this study, and blood (n=400), black hair (n=400), white hair (n=40), and feed (n=40) samples were obtained. Although the feeding regime in these farms was similar, the selenium content of feeds was variable. The Se content of concentrate feeds was 0.104+/-0.086 mg/kg dry matter (DM), and of silage, it was 0.025+/-0.018 mg/kg. A significantly positive correlation was found between the Se concentration in black hair and the Se concentration in blood (r2=0.610, p<0.001), the Se concentration in white hair and the Se concentration in blood (r2=0.770, p<0.001), and the Se concentration in white hair and the Se concentration in black hair (r2=0.921, p<0.001). The Se concentration in white hair was significantly smaller than that in black hair (p<0.001).