Using producers’ own production and financial data from the Kojonup region, modelling was initially undertaken to assess pasture and livestock production, and enterprise profitability for two prior periods (1970-1999 and 2000-2008) to ensure the models were performing correctly. Modelling was then performed looking ahead to 2030, using 4 different climate scenarios.
A Merino x Poll Dorset lamb production enterprise was examined.
Weather predictions & impacts on production and profitability
Projected weather for the four 2030 scenarios and the impact on livestock production and farm profitability, based on a “business as usual” model for a Merino x Poll Dorset lamb production enterprise at Kojonup are shown below:
- Compared to 1970-1999, over the period 2000-2008
- Rainfall was 10% lower and average maximum temperature was 1% higher.
- Profitability of the enterprise was 8% lower
- For 2030:
- The temperature increases are consistent at about 1˚C higher (+5%) but rainfall forecast is more variable ranging from a +3% to – 25%, and averaging a 6% reduction.
- Increased CO2 and temperature will result in an increase in legume content. While this will be positive for animal production, the rate of decline of dry pasture residues over summer may increase, resulting in wind erosion and groundcover limits being reached quicker. This will have ramifications for runoff from non-wetting undulating forest soils in the Kojonup district
- At current district average stocking rates (6.5 DSE/ha for Kojonup) all scenarios except USA 1 showed profit increasing at an average of 17% for the period out to 2030 (range between climate scenarios of -20% to +40%).
- This is quite an unusual finding compared to Ravensthorpe in WA and other locations modelled across southern Australia.
The impact of adaptations
The following table shows the impact of various adaptations on the profitability of a wool sheep enterprise in Yass
- Because mating time and stocking rate are key profit drivers in this area, these were the main adaptations modelled
- In 2030, the biggest increase in profit occurred by maintaining current practices, with little to be gained by:
- mating a month earlier;
- reducing the stocking rate (SR) by 0.5 DSE/ha or increasing the SR by 0.5 DSE/ha.