Endogenous Losses of Nitrogen and Protein Requirement for Maintenance of Sheep

Abstract

Four fistulated and four intact West African dwarf wether sheep, maintained on hay and concentrate supplements were used for a study of metabolic faecal nitrogen (MEN) and endogenous urinary nitrogen (EUN). The composition of the faecal losses was examined. The values obtained enabled calculation of nitrogen requirement of the sheep for maintenance, as well as the value of the experimental rations in the nutrition of the sheep.

Values of MFN obtained by two methods were 3.31 and 3.10 g/kg Dry matter (DM) intake. Endogenous urinary nitrogen value was 0.024 g/day per metabolic weight (W_kg 0.75.)

Analysis of the faeces of the sheep showed that 21.1% of faecal nitrogen (N) were present as microbial and endogenous nitrogen (MEN) and 17.3% was present as water-soluble nitrogen (WSN).

The biological values (BV) of the rations ranged from 85.7% to 100.0%, and the digestible crude protein (DCP) requirement for maintenance, were 1.20 and 0.41 g/day/W_kg 0.75 during the feeding trials.

Values obtained for endogenous N losses and N requirement for maintenance were low compared with reported values and this may indicate adaptation of the dwarf sheep for survival under inadequate dietary protein supply.