Establishment of New Evaluation System for Feed Nutritive Value

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In order to evaluate feed nutritive value for ruminants with digestion in the rumen, small intestine and large intestine, steers fitted with ruminal, duodenal and ileal cannulas were used and fed various by-product diets in comparison with barley diet as a control in three experiments.1.In the experiment 1, when raw-, heated- and defatted-rice bran, or wheat bran was fed ; (1) defatted rice bran increased in situ degradability and decreased prorionate of ruminal fluids, (2) heated rice bran compared with raw rice bran did not affect microbial synthesis and nutrients digestion, and the both full-fat rice brans suppressed the ruminal fiber digestion, and showed a low fat digestibility in the small intestine, (3) the ruminal digestibility of nonstructural nonstarch polysaccharides was less than 30% for the all diets. 2.In the experiment 2, when beet pulp, citrus pulp and soybean hulls were fed ; (1) the in situ degradability for soybean hulls was less than that for the others, (2) the ruminal concentration of acetate was higher for the by-product diets than for the control, (3) the microbial protein synthesis was greater for the beet pulp and the citrus pulp diets, (4) the ruminal digestibility of nostructural nonstarch polysaccharides was less than that of starch, but varied with by-products. 3.In the experiment 3, when high by-product diets with different proportions of heated-rice bran and beet pulp were fed ; (1) a high proportion of the rice bran in the diet resulted in an increase of the ruminal propionate concentration and decreased ruminal fiber digestibility, the microbial synthesis and DE intake, (2) the rice bran content did not affect the digestibilities of fat and nonstructural catbohydrate. 4.Through the three experiments, in situ DM degradability had significant linear relationships with the ruminal digestibility and the microbial synthesis, and this indicates that in situ degradability is an useful variable as a new evaluation method of feed.