A stud animal is a registered animal retained for breeding. The terms for the male of a given animal species (stallion

Stallion (horse)

A stallion is a male horse that has not been gelded .Stallions will follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" neck, as well as a somewhat more muscular physique as compared to...

, bull

Bull

Bull usually refers to an uncastrated adult male bovine.Bull may also refer to:-Entertainment:* Bull , an original show on the TNT Network* "Bull" , an episode of television series CSI: Crime Scene Investigation...

, rooster

Rooster

A rooster, also known as a cockerel, cock or chanticleer, is a male chicken with the female being called a hen. Immature male chickens of less than a year's age are called cockerels...

, etc.) usually imply that the animal is entire—that is, not castrated

Castration

Castration is any action, surgical, chemical, or otherwise, by which a male loses the functions of the testicles or a female loses the functions of the ovaries.-Humans:...

—and therefore capable of siring offspring. A specialized vocabulary exists for de-sexed animals and those animals used in grading up to a purebred status.

Stud females are generally used to breed further stud animals, but stud males may be used in crossbreeding programs. Both sexes of stud animals are regularly used in artificial breeding programs.

A stud farm

Stud farm

A stud farm or stud in animal husbandry, is an establishment for selective breeding of livestock. The word "stud" comes from the Old English stod meaning "herd of horses, place where horses are kept for breeding" Historically, documentation of the breedings that occur on a stud farm leads to the...

, in animal husbandry

Animal husbandry

Animal husbandry is the agricultural practice of breeding and raising livestock.- History :Animal husbandry has been practiced for thousands of years, since the first domestication of animals....

, is an establishment for selective breeding

Selective breeding

Selective breeding is the process of breeding plants and animals for particular genetic traits. Typically, strains that are selectively bred are domesticated, and the breeding is sometimes done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties,...

 using stud animals. This results in artificial selection

Artificial selection

Artificial selection describes intentional breeding for certain traits, or combination of traits. The term was utilized by Charles Darwin in contrast to natural selection, in which the differential reproduction of organisms with certain traits is attributed to improved survival or reproductive...

.

Stud fees

A stud fee is a price paid by the owner of a female animal, such as a horse

Horse

The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...

 or a dog

Dog

The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

, to the owner of a male animal for the right to breed to it. Service fees can range from a small amount for a local male animal of unknown breeding to several hundred thousand dollars for the right to breed to a champion Thoroughbred

Thoroughbred

The Thoroughbred is a horse breed best known for its use in horse racing. Although the word thoroughbred is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed...

 race horse such as Storm Cat

Storm Cat

Storm Cat was an American Thoroughbred stallion whose breeding fee during the peak of his stud career was $500,000, the highest in the world. As such, he was one of the few horses with a 24-hour armed guard....

, who has stood at stud fees of up to US$500,000.

Many owners of high-quality stallion

Stallion

A Stallion is a male horse.Stallion may also refer to:* Stallion , an American pop rock group* Stallion , a figure in the Gobot toyline* Stallion , a character in the console role-playing game series...

s also offer a live foal guarantee

Live foal guarantee

Live foal guarantee is a common provision in horse breeding contracts. It is a form of a warranty offered to the mare owner by the stallion owner...

 with a breeding, usually defined as a guarantee that once the mare

Mare (horse)

A mare is an adult female horse or other equine.In most cases, a mare is a female horse over the age of three, and a filly is a female horse age three and younger. However, in Thoroughbred horse racing, a mare is defined as a female horse more than four years old; in harness racing a mare is a...

 leaves the stud farm

Stud farm

A stud farm or stud in animal husbandry, is an establishment for selective breeding of livestock. The word "stud" comes from the Old English stod meaning "herd of horses, place where horses are kept for breeding" Historically, documentation of the breedings that occur on a stud farm leads to the...

 confirmed to be in foal by a veterinarian

Veterinarian

A veterinary physician, colloquially called a vet, shortened from veterinarian or veterinary surgeon , is a professional who treats disease, disorder and injury in animals....

, she will give birth to a foal that stands and nurses, or else the stud farm will re-breed the mare for no stud fee the following season.

Most stud fees do not include the costs of boarding the female animal at the location of the stud animal, or of the cost of collecting and shipping semen

Semen

Semen is an organic fluid, also known as seminal fluid, that may contain spermatozoa. It is secreted by the gonads and other sexual organs of male or hermaphroditic animals and can fertilize female ova...

 if artificial insemination

Artificial insemination

Artificial insemination, or AI, is the process by which sperm is placed into the reproductive tract of a female for the purpose of impregnating the female by using means other than sexual intercourse or natural insemination...

is used in lieu of live cover. Any veterinary expenses or medications are also an additional cost to the owner of the female animal.