In Ireland, hay has been the traditional fodder offered to sheep during the winter period but the increasing tendency to house ewes before lambing has led to a substantial increase in the use of silage for this purpose. By-products are increasingly used as supplements to these forages, with little relative information available on their value. The objective of this experiment was to compare the effects of feeding grass silage and hay when supplemented with either barley, molassed sugar beet pulp or citrus pulp based concentrates to ewes in late pregnancy on feed intake, ewe weight and body condition changes, gestation length, litter birth weight and colostrum yield.