The Purina mini and pony is probably only available in the States, at least under that name and manufacturer; you might be able to find something similar in Australia. Here's a link to the Purina website, so you can check on the nutritonal analysis for the mini and pony feed; perhaps with that information, you can find something similar in Australia.
http://www.horse.pur...D2-0051041.aspx Or, one of the other Australian members can chime in with feeds available there, that they've had success with.