Concentrate feeding and ruminal fermentation. 2. Influence of concentrate ingredients on pH and on L-lactate concentration in incubations in vitro with rumen fluid.

2. Rumen fluid was sampled before feeding from cows given hay, diluted with an anaerobic salt solution and added (20 ml) to different amounts (mostly 1 g) of maize gluten meal, maize, citrus pulp, tapioca, beet pulp, coconut expeller or soya bean oilmeal for incubation at 39 deg C. After at least 4 h of incubation there were large differences in pH and lactic acid concentration. The acidotic index of the feeds was influenced by increasing concentration of the substrate. Except with maize meal, there was little effect of particle size on pH and lactic acid concentration. There were differences in effect on pH and lactic acid concentration between different batches of the same feeds, especially with maize meal. Incubations with mixtures of concentrate ingredients showed different pH and lactic acid concentrations from values expected from results with the single ingredients. (Abstract retrieved from CAB Abstracts by CABI’s permission