Chemical composition and nutritive value of mature annual legumes for sheep

Abstract

This study reports on the chemical composition and nutritive value of three mature annual legumes: subterranean clover ( Trifolium subterraneum, cv. ‘Junee’), Persian clover ( Trifolium resupinatum, cv. ‘Kyambro’) and a medic ( Medicago murex, cv. ‘Zodiac’). Nitrogen digestibility of Persian clover cv. ‘Kyambro’ in the whole tract was significantly lower than that of the other legumes, although it had the highest nitrogen content. This difference was attributable largely to differences in the digestion of non-fibre nitrogen. Differences in hemicellulose digestibility were also noted. Xylose was the least digestible sugar in all three legumes. Mannose and galactose contents were highest in ‘Kyambro’ and digestibility of these sugars was substantially lower than in the other two legumes. Crossover measurements in situ indicated that components of ‘Kyambro’, possibly galacto-mannans, inhibited rumen fermentation of all three legumes. Concentrations of Ca, P, Mg, K, Na, S, Fe, Cu, Mn and Zn in all legumes were adequate for growth in sheep. In terms of dry matter and nitrogen digestibility, the three legumes were ranked in the descending order: subterranean clover cv. ‘Junee’ > medic cv. ‘Zodiac’ > Persian clover cv. ‘Kyambro’.