When the available dry matter is known the standard intake requirements for sheep can be used to calculate total grazing pressure (TGP) — the total demand for forage by both domestic and non-domestic animals relative to forage supply.
Total grazing pressure is determined by calculating the grazing pressure exerted by domestic and other grazing animals. This provides the most realistic indicator of the number of grazing animals and the grazing pressure being exerted on a paddock. Total grazing pressure is calculated using the standard measure of a dry sheep equivalent (DSE).
The grazing pressure from other animals can be significant and needs to be included when assessing the total grazing pressure of stock in the paddock. Other animals contributing to grazing pressure may include:
- native species (e.g., kangaroos, euros, wallabies)
- wild goat herds
- large feral animals (e.g., camels, horses, donkeys, pigs)
- small feral animals (e.g. rabbits).
Determining a realistic estimate for the non-domestic animals can be difficult as some of the species listed above are quite transient and move within and between properties, depending on levels of feed, water and disturbance.
Grazing management is difficult when non-domestic herbivores contribute to TGP. Try and quantify the TGP of these animals by conducting:
- a ‘step–point transect’ process to assess the levels of dung for different grazing species
- a spotlight survey at night for kangaroos, goats and rabbits, or
- an aerial survey for kangaroos.
To calculate TGP use the Assessing total grazing pressure (TGP) tool. To calculate DSE, use the Calculate DSEs for your property tool.