The grazing value of tall fescue (Festuca arundinacea) and phalaris (Phalaris aquatica) for sheep production in the northern tablelands of New South Wales

摘要

The grazing value of phalaris–white clover and tall fescue–white clover pastures was compared in a temperate summer-rainfall environment in the high rainfall zone of eastern Australia. Data were derived from an experiment which evaluated pasture cultivars when grown in binary mixtures and grazed by sheep. The data were also simulated with the decision support system SheepO (Version 4.0) and validated by visual techniques, deviance measures, and statistical tests. The model generally simulated green biomass, liveweight gain, and clean fleece weight with acceptable accuracy. Pasture based on tall fescue–white clover produced more green pasture biomass in all seasons, in all years, and at both low (10 sheep/ha) and high (15 sheep/ha) stocking rates when compared with phalaris–white clover. Sheep grazing tall fescue–white clover pasture were turned off about 5 kg heavier each year and produced about 0.6 kg/head more clean fleece weight; the wool production per head of sheep grazing tall fescue–white clover at 15 sheep/ha was similar to that for sheep grazing phalaris–white clover pasture at 10 sheep/ha. These differences in wool production were accompanied by consistent effects on wool quality; the fleeces of sheep grazing tall fescue–white clover pasture were markedly sounder in tensile strength but broader in fibre diameter. These data and the SheepO simulations highlight the potential for pasture cultivars with enhanced seasonal growth and nutritive value to alleviate feed-gaps and improve the feed-base for grazing animals.