Hinny is easier to obtain when the lower chromosome count, the donkey, is in the male. Therefore breeding for hinnies is more hit-and-miss than breeding for mules." The male hinny or mule can and will mate, but the emission is not fertile. Male hinnies and mules are usually castrated to help control their behavior by eliminating their interest in females. Female hinnies and mules are not customarily spayed, and may or may not go through estrus. Female mules have been known, on rare occasions, to produce offspring when mated to a horse or donkey, although this is extremely uncommon. Since 1527,
Horse breeding Horse breeding Horse breeding is reproduction in horses, and particularly the human-directed process of selective breeding of animals, particularly purebred horses of a given breed. Planned matings can be used to produce specifically desired characteristics in domesticated horses. Furthermore, modern breeding management and technologies can increase the rate of conception, a healthy pregnancy, and successful foaling. The male parent of a horse, a stallion, is commonly known as the "sire" and the female parent, the mare, is called the "dam". Both are genetically important, as each parent provides half of the genetic makeup of the ensuing offspring, called a foal.