Its origins are not documented, but it is thought to derive from crossbreeding of Ayrshire, Devon, and Dairy Shorthorn.
In an official test in 1998, Illawarra cows averaged 4,829 litres of milk, with slightly over 4% butterfat and 3.4% protein, under Australia's pasture production system.
[1] According to the 2010 Australian Dairy Herd Improvement Report, the average production of an Illawarra cow is 6733 litres with a butterfat content of 3.95% and a protein level of 3.29%.
They make good handling cattle for shows and are easy to work with in the dairy.
[citation needed] Illawarra cattle, embryos, and semen have been exported to Central America, Indonesia, Japan, Korea, Canada, the Middle East, New Zealand, the Pacific Islands, Pakistan, the United Kingdom, and the United States.