All Thoroughbred horses have the same ‘’Birthday’’ which is 1st August in the Southern Hemisphere and 1st January in the Northern Hemisphere.
In Australia Thoroughbred breeders aim to have foals born as soon as possible after August 1st so it’s true age will be approaching one year when it reaches its first official first birthday on August 1st. For this reason, the covering season begins 1st September. Foals born late in the season, say in November, will be at some disadvantage in terms of growth and maturity to their older peers born in August and September, when they all become yearlings on August 1st