Effect of Several Variables on in Vitro Rumen Fermentation

Abstract

The effect of several variables on dry matter and cellulose digestion and/or volatile fatty acid production was determined by in vitro rumen fermentations. The percentage of cellulose and dry matter digestibility were improved by a reduced concentration of substrate and an increase in rumen liquor. Mineral media concentration had little effect. Different sources of rumen liquor markedly effected substrate digestion, with significant differences between twin steers in 2 trials; pH adjustment significantly influenced cellulose digestibility. The optimum pH may be dependent on the rumen liquor source. Decreasing particle size of an alfalfa substrate depressed dry matter and cellulose digestibility, but had no affect on peavine hay.