Supplementation of a typical Danish winter ration with 2 g. of DL-α-tocopherol acetate per cow per day did not result in an increased yield of milk or milk-fat. The keeping quality of the butter was practically uninfluenced or possibly slightly reduced by the supplementation. The supplementation caused a rise in the tocopherol content of the butter from 10 to 12µg./g. in the unsupplemented group to 23–26/µg./g. in the supplemented group. After the experimental period the amount of total tocopherol in the butter decreased rapidly. It increased again when the cows went to pasture.

Butter-fat obtained from the unsupplemented group with 9·6–13·2µg. tocopherol/g. and from the supplemented group with 27·3–31·2µg. tocopherol/g. did not produce encephalomalacia in chicks when incorporated at a level of 30% instead of lard in a suitable test diet, but the amount of tocopherol present, especially in the butter-fat from the unsupplemented group, was not sufficient to prevent white striation of breast muscles in chicks under the same conditions.