A stud animal is a registered animal retained for breeding. The terms for the male of a given animal species (stallion, bull, rooster, etc.) usually imply that the animal is intact—that is, not castrated—and therefore capable of siring offspring. A specialized vocabulary exists for de-sexed animals (gelding, steer, etc.) and those animals used in grading up to a purebred status.[1]
Stud females are generally used to breed further stud animals, but stud males may be used in crossbreeding programs.[2] Both sexes of stud animals are regularly used in artificial breeding programs.
A stud farm, in animal husbandry, is an establishment for selective breeding using stud animals.[3] This results in artificial selection.