The Australian Racehorse

In order to race in an official event in Australia, the horse must be registered with the Registrar of Racehorses.
The Age Of A Racehorse
Horses must be at least two years old before it can race in any event; at least 3 years old for hurdles and at least four years old for steeplechase.
In general, older horses favor long races and younger horses dominate sprints.
The Horses Birthday

The horses birthday is taken from August 1st in the year in which it was foaled. If it was foaled between the first day of January and the thirtieth day of June, the age is determined as August 1st in the year previous to the year in which it was foaled.
The Male Racehorse
Male horses are known as colts until the age of five, and known as horses thereafter;
The Female Racehorse
Females are known as fillies until five years old and then known as mares thereafter.
What Is A Gelding?
a gelding is a castrated colt or horse.