EFFECTS OF BLOOD MEAL, FISH-MEAL, SOYBEAN-MEAL OR CASEIN ON RUMEN PROTEIN-METABOLISM IN LAMBS

In the first of two experiments four rumen-cannulated sheep were used to determine the degree of rumen protein degradation in blood meal (BM), fish meal (FM), soybean meal (SBM) or casein (C) using the in sacco method. In the second experiment, four cannulated rams were fed isonitrogenous and isoenergetic diets to ascertain the influence of the same protein feeds on metabolic changes in the rumen and flow of amino acids through the duodenum. Rumen non-degradable N in BM, FM, SBM or C total-N was 74%, 62%, 38% and 11%, respectively. Rumen ammonia-N (NH3-N) was highest (P < 0.05) in lambs fed C, lowest with FM. Source of dietary protein did not affect dry matter or organic matter digestibility in the rumen. Total-N, non-ammonia N and amino acid flow through the duodenum was highest (P < 0.05) in lambs fed FM and lowest with C. Combinations of protein sources may best supply amino acids to ruminants in optimal proportions.