Gas production and dry matter degradability of diets for ruminants

Summary Four feeds widely used in ruminant nutrition (corn silage, alfalfa hay, corn grain and soybean meal) and nine diets prepared in the laboratory by thorough mixing of these four feeds in different ratios, were analysed for: chemical composition according to the Weende and Van Soest schemes. Starch content, as well as total gas production and dry matter degradability after 8, 24 and 48 hours of incubation were measured. The same parameters were calculated for the nine diets from the measurements made on each of the four components (i.e. estimated values). For the chemical determinations, the differences between the analytical results (real values) and the corresponding estimated values varied little and did not reach statistical significance. However, statistically significant differences (P<0.05) between real and estimated values appeared for gas production at 24 hours (48.07 vs. 44.13 ml/200mg DM) and for DM degradability after 8 hours of incubation (32.35 vs. 30.56 %). The differences in the gas production measurements were removed when Diet 1 was excluded.