Falling prices for cereals and beneficial effects on milk protein concentrations may promote greater inclusions of rapidly fermented ingredients in dairy rations. There is, however, a limit to the inclusion of these feeds into dairy rations beyond which performance declines due to sub-acidosis and related disorders. The feed compounder will need to be able to set limits on levels of feeding concentrates according to these risks. The objective of this experiment was to evaluate the effect of feeds of different acidogenicity (Wadhwa et al., 1998) on lactation performance of dairy cows offered diets based on grass- or maize-silage.

Twelve multiparous Holstein-Friesian cows in the third month of lactation were used for this experiment. The experimental design involved adaptation and covariance recording on a standard diet (grass silage and 10 kg concentrates per day), followed by three 21-day experimental periods arranged as four 3x3 Latin Squares. The Latin Squares were constrained to a single forage to avoid difficulties in changeovers between grass silage and maize silage.