Effect of white clover rich grass pasture allowance on α-tocopherol and selenium content in cow milk

The objective of this study was to examine the effect of high (HPA, 24 kg DM/cow per day) and low (LPA, 12 kg DM/cow per day) pasture allowance of a white clover rich grass pasture on a-tocopherol and selenium in milk. Four multiparous cows of Norwegian Red were used in a Latin square design. Two experiments were conducted: Experiment 1 in mid pasture season with 7 kg concentrate per cow/day, and experiment 2 in late pasture season with 3 kg concentrate per cow/day. In mid pasture season, milk a-tocopherol concentration was higher on the HPA treatment; 0.63 mg/kg, compared to the LPA treatment; 0.28 mg/kg (P=0.09). However, this effect was not seen in late pasture season. There was no statistically significant effect of pasture allowance on milk selenium (mean 10.6 mu g/kg) in these experiments.