Following the introduction of milk quota many farmers attempted to place greater reliance on home grown forage as a means of decreasing concentrate inputs and thus reducing input costs. As a high energy forage, maize silage should have the potential to increase forage intake and influence milk yield and quality. The objective of the current trial was to examine the effect on forage intake and milk production of incorporating maize silage into rations based on grass silage with average or high energy concentration.

Sixty-three multiparous and 28 primiparous Friesian cows were used in a trial lasting 20 weeks. Following a two week covariate period cows were allocated to treatment. Treatments were based on forage mixtures of maize silage and grass silage of either average (A) or high (H) energy value in which maize formed 0, 25, SO or 75% of the forage mixture DM.