For the 2018 analysis GrassGro™ was used to calculate the financial performance of each bloodline.
GrassGro™ is a decision support tool that uses historical weather data to drive models of pasture growth and animal production, with changes in the water content of the soil, pasture growth and decay, and responses to grazing.
The greasy fleece weight, yield, fibre diameter and liveweight for each of the 73 bloodlines provided the livestock production parameters.
Enterprise structure, prices and costs were held constant and were reflective of a wether enterprise, with wethers shorn three times and then sold.
Median wool and mutton prices for the 5 years from 2013 to the end of 2017 were used, as well as low (30 percentile) and high (70 percentile) wool prices. The median mutton price used was 338c/kg carcass weight, whilst the mutton price for the low price (30%) scenario was 295 c/kg, and the high (70%) scenario was 368 c/kg.
| Low (30%)|
| Median (50%)|
| High (70%)|
The stocking rate (wethers/ha) was chosen such that the bloodline with the median liveweight would achieve the rule of maintaining a minimum ground cover of 70% for any day in 71% of the years.
The GrassGro™ simulations used typical soil, pasture and weather conditions for three sites, representing three different environmental systems with typical pastures for each location:
The GrassGro™ simulations generate an annual profit for each bloodline during the simulation period, from 1963 to the end of 2017, which accounts for the full range of seasonal conditions from drought through to long wet years. From this information, two measures of financial performance are provided:
The standard deviation of profit provides an indication of the variation around the average profit. A large standard deviation indicates greater variation in profit compared with a smaller standard deviation.
The 2018 analysis continues to report measures of the variability in financial performance of the bloodlines - the standard deviation (St dev) of profit on both a $/hd and $/DSE basis.