The effect of dicalcium phosphate supplements on the intake and digestibility of Townsville lucerne and spear grass by sheep

Abstract

Sheep were fed either Townsville lucerne (Stylosanthes humilis) or spear grass (Heteropogon contortus) with and without dicalcium phosphate for an 11-week period. Voluntary intake, dry matter digestibility and liveweight changes of the animals were measured. Sheep fed Townsville lucerne gained body weight whereas those fed spear grass lost weight. Added dicalcium phosphate (4.5 g/day) increased dry matter intake and liveweight gain of the sheep fed Townsville lucerne, but not the digestion coefficient. Sheep consuming spear grass did not respond in any way to the supplement. All sheep fed spear grass received urea daily (2.9g N/day) as a nitrogen supplement. The difference between the two groups in response to dicalcium phosphate is discussed in terms of the chemical composition of the two feeds.