The effect of spreading sodium bicarbonate over the surface of grass silage on the intake of grass silages by beef cattle

Ten silages were obtained from farms in Northern Ireland. They were selected on the basis of either low pH (< 3.7) or perceived low intakes on the farms. The silages were offered to 100 Charolais cross steers, either with or without the addition of sodium bicarbonate, in a two-period changeover design experiment. The sodium bicarbonate was spread over the surface of the silage at a rate of 250 g per steer day−1. Each period was of a 2-week duration. Dry matter intakes (kg day−1 and g kg−1 liveweight (LW)0.75) were recorded daily, with intakes on the second week of each period being used in the statistical analysis. Silage dry matter intakes with (+) and without (−) dietary addition of sodium bicarbonate were: 6.27 and 6.16 (SEM = 0.122) kg day−1; 65.8 and 64.7 (SEM = 1.29) g kg−1 LW0.75. The lack of a significant effect of dietary addition of sodium bicarbonate on the intake of low pH silages suggests that sodium bicarbonate spread over the surface of the silage has no beneficial effect, in terms of intake, with silages of this type.