The effect of stocking rate and deferred Autumn grazing of pasture on liveweight and wool production of Merino wethers in a Mediterranean-type climate

Abstract

Liveweight, seasonal wool growth rates, annual wool production, wool quality and hand feeding requirements were recorded for Merino wethers when autumn deferred or continuously grazed. The two management systems were compared at a series of eight stocking rates from 12.4 to 29.7 sheep per hectare for five years from 1967 to 1971 at the Kybybolite Research Centre, South Australia. Autumn deferment resulted in increased liveweight and wool growth rate during the months of June to September. However, liveweights and wool production under either management were similar for the remainder of the year. Because deferred grazing did not increase liveweights during the critical autumn period, and since hand feeding requirements were similar under either management system at the higher stocking rates, it is suggested that yearly stocking rates can not be increased by autumn deferment. Apart from the drought year of 1967, the continuously grazed sheep required little or no hand feeding up to 22.2 wethers per hectare. It is unlikely that the cost of hand feeding deferred sheep up to this stocking rate would be covered by the small increase in wool production. However, this would depend on the cost of conserved fodder and price received for the wool.