1980•Proceedings of the Australian Society of Animal ProductionRequires access
Digestion of high fibre roughage in the rumen of sheep.
L. C. L. Freire, A. N. Boniface, Robin M. Murray
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Abstract
The extent of digestion of high fibre spear grass (Heteropogon contortus) hay by sheep was examined to determine the factors which limit its utilization. The mean organic matter (OM) intake (22 g/kgu.'3/day) and digestibility (39%) were low and all animals were in negative energy and nitrogen balance. Mean retention time in the rumen for the liquid phase marker (Cr-EDTA) was long (17.9 hours) and 71% of OM digestion took place in the rumen. Total volatile fatty acid production rate was low (0.88 moles/day) representing 11.3 moles/kg OM digested in the rumen. Microbial protein synthesis (3.4 g N/day), measured by 35S incorporation into rumen micro-organisms, accounted for all the non-ammonia nitrogen flowing to the abomasum, representing a net increase over that ingested of 2.4 g N/day.