Of the cereals grown in the UK oats, and especially the recently developed naked oats, contain relatively large amounts of C18 fatty acids. Consistent with this, in a series of change-over type experiments substitution of oats or naked oats for barley in dairy cows’ rations reduced the proportion of saturated fatty acids and increased that of monounsaturated fatty acids in milk fat (Martin & Thomas, 1988a, b). These results indicated the inclusion of oats in cows’ diets to be a means of increasing the appeal of milk and milk products to the health-conscious consumer. The present experiment was conducted to assess the likely potential for dietary manipulation of milk fat composition using naked oats under commercial farming conditions.

Thirty-two Friesian cows and heifers were used in a continuous design feeding trial which extended from week 3 to week 18 of lactation. The animals were paired on the basis of calving date, lactation number and pre-trial milk yield and, within pairs, were allocated at random to one of two diets.