Evaluation of New Pasture Legume Species in Terms of Summer Feeding Value and Effects on Wool Production.

86KA71, Pasture legumes improve the feeding value of summer pastures in a mediterranean-type environment by maintaining the protein intake of grazing animals over the dry summer period, much of which comes from the ingestion of legume burr (A.D. Wilson and N.L. Hindley, 1968). Some of the most important species of pasture legumes to have been released commercially are Trifolium subterraneum (sub.clover), Medicago truncatula (barrel medic) and Medicago polymorpha (burr medic) (D.B. Purser, G.B. Taylor and W.J. Collins, 1987). What little information is available on the feeding value of these species suggests that barrel medic pod (H. Brownlee, 1973) and dry sub.clover pasture (D.B. Purser, unpublished data, as quoted in D.B. Purser et al., 1987) do not supply sufficient nutrients to permit the maintenance of body weight. Field observations however, have shown that sheep grazing burr medic pastures over summer are more productive than sheep grazing sub.clover or grass pastures. There is a wide range in pod structure and chemical composition between and within the different species of pasture legumes and this is likely to affect their feeding value. It is particularly relevant to consider the pod\u27s content of seed because it is the seed that provides the main source of nutrients, especially lipids and proteins (G.D. Denney, J.P. Hogan and J.R. Lindsay, 1979). Preliminary research at Katanning (Western Australia) has shown that the pod:seed ratio of barrel medic is only approximately 35% whereas the pod:seed ratio of the burr medics Circle Valley and Serena is approximately 50%. This finding suggests that the quality of burr medic pod is likely to be superior to the quality of barrel medic pod