Colt

A colt is an ungelded male horse four years old or younger. From five he is described as a horse or entire. The distinction matters commercially — a colt winning a Group 1 acquires stallion value that far exceeds prize money — and behaviourally, since colts can be more temperamental in the yard and the barriers than geldings. Many colts are gelded when their racing manners or ability fall short of stud prospects.