The objective of this work was to validate the technique of gas production in the evaluation of concentrated feeds and roughages, and the possible differences between cattle, sheep, and goats, regarding the degradation of these feeds. The experiment was carried out in the Laboratory of Animal Research at the Animal Science Department - Federal University of Lavras, Brazil. The ruminal liquor came from three Holstein cows, three sheep, and three goats, without defined race. All were fistulated in the rumen. The neutral detergent soluble fraction (NDS) and neutral detergent fiber (NDF), of ground corn, soybean meal, cotton meal, cotton seed, wheat meal, citrus pulp, alfalfa hay, coast cross hay, corn silage and grass silage were evaluated. The readings of the cumulative volume of gas were made from 1 to 72 hours after incubation. There was not difference (P >0.05) among the animal species, for any of the studied variables. The NDS fraction presented larger gas production and degradation rate in relation to NDF. The gas production technique allowed to estimate the rates of digestion of the insoluble fractions and, mainly, the soluble fractions of the total carbohydrates.
Degradability; gas production; cattle; sheep; goat
