Cell Grazing Worm Control

Summary

Cell grazing describes intensive rotational grazing between 20 to 50 paddocks and with a flexible rotation interval based on assessed herbage mass on offer. The herbage mass or feed on offer (FOO) is quantified visually by a trained stockman and recorded as dry sheep equivalent (dse) or stock days per hectare (DDH). This is an estimate of carrying capacity - how long a specific number of stock can graze a paddock without overgrazing. Grazing pressure, or stock density, is generally maintained at 200 to 500 dse per hectare during the grazing phase to promote quick, even harvesting of pasture over the entire paddock. Emphasis is placed on how long a paddock is rested between grazing periods to allow adequate plant recovery.

Cell grazing is different to time controlled grazing, where the stock are moved between paddocks at set intervals regardless of the residual feed on offer; or set stocking, where the stock remain in a paddock for weeks, or even months. Warn et.al. (2001) demonstrated in a three year trial in central north Victoria that 20 percent more stock could be carried under cell grazing than set stocking, without compromising per head production. Even simple rotation between four paddocks showed a ten percent advantage in stocking rate compared to continuous grazing, given adequate phosphorus input.

The impact of cell grazing on worm populations is not well understood. The recent increase in adoption of cell grazing has lead to the belief that worms are less likely to be a problem under cell grazing. This project was initiated to compare the production loss due to worms incurred under cell grazing and traditional set stocking.