A note on the effects of the method of inclusion of sodium bicarbonate and diet composition on the intake of diets based on silage by dairy cows

Abstract

Sodium bicarbonate had no effect on the dry-matter (DM) intake of heifers given a complete mixed diet of grass silage, molasses, barley, soya-bean meal and a mineral mix (660, 140, 100, 85 and 15 g/kg DM respectively) when it was incorporated into the mix at 20 and 40 g/kg DM or sprinkled on top of the diet at a rate of 350 g/day. In a second experiment, cows in mid lactation were given a complete mixed diet of silage, barley, soya-bean meal and minerals (660, 240, 85 and 15 g/kg DM) or the same diet with the barley replaced with molasses at 140 g/kg DM. Sodium bicarbonate was sprinkled on top of the diets at 0, 450 or 900 g/day. There were no significant effects on DM intake in the final week of each 3-week period. However, there was an apparent interaction of diet and sodium bicarbonate on the initial acceptance of the diet, with the intake of the diet in week 1 being significantly lower than the final intake with 900 g/day sodium bicarbonate in the absence but not in the presence of molasses.