PASTURE COMPOSITION UNDER MIXED SHEEP AND GOAT GRAZING ON HILL COUNTRY

Abstract

Hill country pasture was grazed by the following ratios of goats and sheep from 1979-l 983: 100% goats (Goat 100). 66% goats and 34% sheep (Goat 66)) 33% goats and 67% sheep (doat 33), 100% set-stocked sheep (Sheep 100) and 100% mobstocked sheep. Changes in botanical composition, herbage mass and herbage accumulation rate were measured by sample dissection, visual estimation and trimmed exclosure cages respectively on three slope classes (banks, slopes and tracks). Pastures grazed by goats developed Yorkshire fog IHolcus lanatus)- white clover (Trifolium repens L.) associations with strong white clover growth on all slope classes unlike sheep-grazed pastures which contained little white clover and were dominated by perennial' ryegrass (Lolium perenne L.) and browntop (Agrostis tenuis Sibth.). The herbage mass of 3000, 1830, 1410 kg DM/ha on banks, slopes and tracks respectively for Sheep 100 pastures contrasted with that on the Goat 100 pastures of 2030, 3750 and 4300 kg DM/ha. White clover was enhanced on all slope classes in the Goat 100 treatment. Annual herbage accumulation was greater on the Goat 100 than Sheep 100 pastures, 13.9 and 11.2 t DM/ha respectively. There was a close association between increased annual white clover accumulation and tofal herbage accumulation. The complementary nature of sheepandgoatgrazing behavioursuggeststhe possibility of increased meat and fibre production from mixed grazing. The implications of these results for future research are discussed. Keywords: Sheep, goats, herbage mass, herbage accumulation rate, botanical composition, slope classes, white clover (Trifolium repens L.), perennial ryegrass (Lolium perenne L.), Yorkshire fog (Holcus lanatusl, browntop (Agrostis tenuis Sibth.).