Nitrogen and Sulphur Retention and Fibre Digestion by Euros, Red Kangaroos and Sheep.

Abstract

Retention of nitrogen and sulphur, and digestion of various carbohydrate fractions, were measured in euros, red kangaroos and sheep, fed three different quality roughages in an experiment of three 3 by 3 latin squares. Sheep ate more dry matter (DM) and digestible energy (DE) per unit metabolic body weight than the euros or red kangaroos, but there were no significant differences in DM intakes between euros and red kangaroos. Despite lower DE intakes, euros lost less weight on the poor-quality diet than sheep. The euros digested more DM and consumed more DE than the red kangaroos, which lost more weight than either the euros or the sheep on the poor-quality diet. Maintenance energy requirements were calculated to be 136, 109 and 99 kcal DE per kg W0*76 per day for the sheep, red kangaroos and euros, respectively. Digestibility of structural carbohydrates was not significantly different between sheep and euros, but both species were more efficient than the red kangaroos. Also, there were no significant differ- ences in nitrogen or sulphur balance between sheep and euros, but both retained more nitrogen and sulphur per unit metabolic body weight than red kangaroos. Faecal nitrogen and sulphur losses were similar in euros and red kangaroos, but red kangaroos excreted more nitrogen and sulphur in their urine than euros. It is concluded that the red kangaroo is less efficient than the euro or sheep in retaining nitrogen and sulphur, and in digesting fibre, when fed poor-quality roughage diets.