A castrated horse is called a Gelding.
A castrated young horse is called a gelding.
A castrated male horse, regardless of age, is called a gelding.
A castrated horse is usually referred to as a gelding. An incorrectly castrated horse, one that retains some testicular tissue that produces testosterone, is called a ridgeling.
ah, i think you already know the answer if you say 14.2hh.