Just a few questions

As it seems to me that there is a huge difference in horse racing in australia as compared to america i have a few queations to ask.
What is the breeding season in usa ? sept to jan in aussie
When is a foal a yearling ? in australia its 1st august
I also saw a few comments about horses that seem to be retired after there 3 rd year ? wow if thats true watch out. over here some horses don't run untill their 3rd year & though few & far between oldtimers as old as 10 year olds still win major races over here.