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.
Selective breeding is the process of breeding for particular traits. Typically, strains that are selectively bred are domesticated, and the breeding is sometimes done by a professional breeder. The cross of animals results in what is called a crossbreed, The term selective breeding is synonymous with artificial selection.
Horses with homogeneous appearance, behavior, and other characteristics are known as particular breeds, and they are bred through culling particular traits and selecting for others. Purebred animals have a single, recognizable breed, and purebreds with recorded lineage are called pedigreed. Crossbreeds are a mix of two purebreds, whereas mixed breeds are a mix of several breeds, often unknown. Horse breeding begins with breeding stock, a group of animals used for the purpose of planned breeding. When individuals are looking to breed horses, they look for certain valuable traits in purebred stock for a certain purpose, or may intend to use some type of crossbreeding to produce a new type of stock with different, and, it is presumed, superior abilities in a given area of endeavor.
Purebred breeding aims to establish and maintain stable traits, that horses will pass to the next generation. By “breeding the best to the best,” employing a certain degree of inbreeding, considerable culling, and selection for “superior” qualities, one could develop a bloodline superior in certain respects to the original base stock. However, on the other hand, indiscriminate breeding of crossbred horses may also result in degradation of quality.
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. (Contrary to popular misuse, the word “colt” refers to a young male horse only; “filly” is a young female.)
Though many horse owners may simply breed a family mare to a local stallion in order to produce a companion animal, most professional breeders use selective breeding to produce individuals of a given phenotype, or breed. Alternatively, a breeder could, using individuals of differing phenotypes, create a new breed with specific characteristics.
Breeding and Gestation
While horses in the wild mate and foal in mid to late spring, in the case of horses domestically bred for competitive purposes, especially horse racing and various futurities, it is desirable that they be born as close to January 1 in the northern hemisphere or August 1 in the southern hemisphere as possible so as to be at an advantage in size and maturity when competing against other horses in the same age group. When an early foal is desired, barn managers will put the mare “under lights” by keeping the barn lights on in the winter to simulate a longer day, thus bringing the mare into estrus sooner than she would in nature. Mares signal estrus and ovulation by urination in the presence of a stallion, raising the tail and revealing the vulva. A stallion, approaching with a high head, will usually nicker, nip and nudge the mare, as well as sniff her urine to determine her readiness for mating.
Care of The Pregnant Mare
Domestic mares receive specific care and nutrition to ensure that they and their foals are healthy. Mares are given vaccinations against diseases such as the Rhinopneumonitis (EHV-1) virus (which can cause abortions) as well as vaccines for other conditions that may occur in a given region of the world. Pre-foaling vaccines are recommended 4–6 weeks prior to foaling to maximize the immunoglobulin content of the colostrum in the first milk. Deworming the mare a few weeks prior to foaling is also important, as the mare is the primary source of parasites for the foal.
Foals develop rapidly, and within a few hours a wild foal can travel with the herd. In domestic breeding, the foal and dam are usually separated from the herd for a while, but within a few weeks are typically pastured with the other horses. A foal will begin to eat hay, grass and grain alongside the mare at about 4 weeks old; by 10–12 weeks the foal requires more nutrition than the mare’s milk can supply. Foals are typically weaned at 4–8 months of age, although in the wild a foal may nurse for a year