Malt distillers wet grains (MDG) are an important feed source of ruminants in Scotland with an annual production of 220,000 T. Ensiled MDG is commonly fed to ewes but little information is available on the optimal inclusion level in the diet for pregnant ewes. Of particular interest is the maximum inclusion rate as MDG is frequently the least cost dietary component. MDG are high in unsaturated oil, which, owing to its inhibitory effect on rumen bacteria, results in reduced intakes and digestibility of diets containing high levels of MDG. Furthermore MDG are devoid of soluble minerals such as potassium and sodium. Previous experiments with cattle (Lewis and Lowman, 1987) and lambs (Vipond et al, 1992) have shown that supplementation of MDG with a mineral mix (MDG mineral) containing high levels of potassium, calcium and magnesium can overcome these deficiencies and promote higher intakes and improve performance. Such a mineral was used in this trial.