The use of ruminal ammonia and blood urea as an index of the nutritive value of protein in some food-stuffs

Abstract

1. Nine successive trials with three adult desert rams were carried out, with the aim of using ruminal ammonia or blood urea concentration as an index of the nutritive value of the proteins in the various types of forage grown in irrigated parts of the northern Sudan.The change in the ruminal ammonia and blood urea concentration were considerably higher 3 h after feeding on leguminous forages than on the non-legumes. Among legumes, lubia and lubia hay produced the highest concentrations of both rumen ammonia and blood urea. Feeding the rams on berseem hay reduced the concentrations of ruminal ammonia and blood urea to levels below those given by feeding on fresh berseem.3. Most of the nitrogen excretion from leguminous forages was in the form of urinary nitrogen whereas for grasses faecal nitrogen made up the bulk of the nitrogen excreted. Berseem hay gave the highest nitrogen retention, followed by the butterfly pea and fresh berseem. Lubia and lubia hay gave the lowest nitrogen retention. The desert grasses produced a negative nitrogen balance when offered to the desert rams.