The OM digestibility of silverleaf desmodium is rather low (48-57%) and even much lower values have been recorded (19%, Mtimuni, 1978). However, the true intestinal digestibility of DM, nitrogen and amino acids was higher for silverleaf desmodium than for cowpea (Vigna unguiculata), and rumen-undegraded protein supplied postruminally could be used for productive processes such as milk production and growth (Baloyi et al., 2009).
Use as a supplement
Due to its high tannin content, silverleaf desmodium would be better fed only at low proportions in the diet. Feeding after drying may be advantageous because the amount of condensed tannins will have decreased (Baloyi et al., 2001).
When used to supplement Hyparrhenia-dominant pastures (veld) in Zimbabwe (25% of forage intake), silverleaf desmodium hay was less efficient than hays from stylo (Stylosanthes guianensis) and siratro (Macroptilium atropurpureum) for increasing intake, digestibility and live-weight gain in growing lambs (Matizha et al., 1997). In a similar experiment, silverleaf desmodium hay also resulted in a lower intake than cowpea (Vigna unguiculata) and Stylosanthes scabra hays, though DM and OM digestibilities were identical to those obtained with those legumes. The 3 legume hays increased DM and N utilization but N retention remained negative (Baloyi et al., 2006).
During a series of experiments in Zimbabwe in which steers grazed veld sown with silverleaf desmodium for several years, dry season weight losses were significantly lower and wet season weight gains were higher than in steers grazing unimproved veld. Early growth was grazed hard. Even when only the bare stems were left due to frost they were able to increase the protein content of the diet. However, the legume induced botanical changes resulting in weed invasion. In winter, the silverleaf desmodium pasture lost part of its nutritive value, due to trampling and frost, and it was proposed to use legume trees such as Leucaena leucocephala instead (Clatworthy et al., 1980a; Clatworthy et al., 1980b; Clatworthy et al., 1980c; Clatworthy, 1984).