Yearling castrated cashmere bucks grazed continuously from late May until late July, mixed perennial ryegrass/white clover (Lolium perenne/Trifolium repens) swards maintained at either 4 or 8 cm sward surface heights. The goats achieved higher liveweight gains on the 8 cm than on the 4 cm treatment (85.6 vs. 43.3 g LV/day; SED = 17.78; P<0.05) having an overall extra benefit of 314 kg LV/ha in the 8 cm swards. The proportions of clover in the swards increased during grazing in the whole sward (P<0.05) and on the sward surface (P<0.001) of both height treatments and their percentages plus the sward height had an effect (r² = 0,915; P<0.05) on the goat liveweight changes. It is concluded that responses of liveweight gain of weaned bucks to sward height are better at 8 cm than at 4 cm on mixed grass/clover swards managed with clover contents that range between 20% and 40% sward canopy composition.