J.H. AHN¹, R. ELLIOTT¹ and D.J. MINSON²

¹Department of Agriculture, University of Queensland, St Lucia, Queensland, 4067.
²CSIRO Division of Tropical Crops and Pastures, 306 Carmody Road, St Lucia, Queensland, 4067.

Abstract

The nutritive value of hays made from Cassia rotundifolia cv. Wynn and Medicago sativa cv. Trifecta (lucerne) was compared in 2 experiments. In the first experiment, 16 adult wether sheep were fed (ad libitum) either cassia hay or lucerne for 35 days. Digestibilities of dry matter and nitrogen in the cassia were 55 and 66% respectively. Both values were significantly (P < 0. 05) less than the corresponding values for lucerne hay (65 and 81% respectively). Sheep fed cassia hay exhibited significantly lower (P < 0. 05) nitrogen retention than animals offered lucerne hay (5.4 versus 24.6 gN/d).
In a second experiment, microbial protein production in the rumen was measured using abomasally fistulated sheep fed the 2 hays. The mean efficiencies of microbial protein production were 166 g and 223 g protein/kg organic matter fermented in the rumen for sheep fed cassia and lucerne hays respectively.
It is concluded that cassia hay cut at a mature stage of growth has the expected nutritive value and voluntary intake based on its chemical composition and appears to be free of noxious compounds.