The vitamin D activity of pastures and hays.

There is not much information about the vitamin D content of fodders and hay. Most of it is from the United States and, more recently, Holland. Keener (1954) and Weits (1956) have summarized the available information. No such assessments apparently having been made in this country, an opportunity was taken to make a systematic study of the vitamin D activity of Scottish hill pastures. Monthly samples were obtained from one pasture during the sheep-grazing period in 3 consecutive years, and the vitamin D activity of the grass fat was determined. While this investigation was in progress experiments were begun at Shinfield to compare the nutrient content of hay made by the orthodox use of the pick-up baler (ground-cured) or on tripods with that of the original sward (Murdoch, Foot, Hosking, Line & Rowland, 1959; Thompson, 1959). Vitamin D assays were done on some of the samples and the results are also reported here.