Influence of Spring Grazing Management on Summer Autumn Production of Dairy Pastures

Three grazing treatments were allocated at random within e11ch of five 2.6 ha paddocks of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) pasture. The treatments involved variation i'n the timing and degree of control of ryegrass reproductive growlh in two successive pasture growth seasons (1990-91 and 1991- 92). In 1990-91, swards in which reproductive growth was controlled at anthesis (20 November; LHC) produced 4330 kg OM/ha between 18 December and 11 April, compared with 3980 kg DM/ha for swards controlled on 18 December (VLHC) and 3210 kg OM/ha for swards controlled on 9 October (BC). In 1991-92, a "late lax" control (LLC), involving progressive return to close conlrol over three successive grazings, proved to be most effective in enhancing summer production. Herbage production was 3420, 3250, and 3880 kg OM/ha between 12 December and 17 March from treatments BC, LHC, and LLC, respectively.