Liveweight gain of weaned lambs grazing swards increasing, decreasing or at constant surface heights

During the early grazing season, when a high proportion of the lambs nutrient requirements are supplied by milk, high rates of growth can be achieved by sward management which maintains a constant surface height (3-5.5 cm) (Maxwell, Lloyd and Dickson, 1985). In late lactation, increasing herbage Intake rarely compensates for reduced milk supply and lamb growth rates are commonly lower than could be achieved with concentrate diets (Doney et al, 1984; Lloyd et al 1987). Lamb growth in this period may be related to increase or decrease of sward height (Alcock, Clark and Harvey, 1986; Maxwell, Lloyd and Dickson, 1985) or to changes in herbage growth rate (Doney, Smith, Sim and White, 1986). The present study investigated the effect on daily live-weight gain (DLWG) in weaned lambs of herbage growth rate (HGR) and pattern of sward height (SH) change when varied independently.