Terminal crossbreeding

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Terminal crossbreeding is a breeding system used in animal production. It involves two (different) breeds of animal that have been crossbred. The female offspring of that cross is then mated with a male (the terminal male) of a third breed, producing the terminal crossbred animal. [1]

A breed is a specific group of domestic animals having homogeneous appearance (phenotype), homogeneous behavior, and/or other characteristics that distinguish it from other organisms of the same species. Breeds are formed through genetic isolation and either natural adaptation to the environment or selective breeding, or a combination of the two. Despite the centrality of the idea of "breeds" to animal husbandry and agriculture, no single, scientifically accepted definition of the term exists. A breed is therefore not an objective or biologically verifiable classification but is instead a term of art amongst groups of breeders who share a consensus around what qualities make some members of a given species members of a nameable subset.

Mating The pairwise union of individuals for the purpose of sexual reproduction, ultimately resulting in the formation of zygotes.

In biology, mating is the pairing of either opposite-sex or hermaphroditic organisms, usually for the purposes of sexual reproduction. Some definitions limit the term to pairing between animals, while other definitions extend the term to mating in plants and fungi. Fertilization is the fusion of both sex cell or gamete. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization. Mating may also lead to external fertilization, as seen in amphibians, fishes and plants. For the majority of species, mating is between two individuals of opposite sexes. However, for some hermaphroditic species, copulation is not required because the parent organism is capable of self-fertilization (autogamy); for example, banana slugs.

The first crossbreeding may produce a superior animal due to hybrid vigor. Often, this crossbreed is part of a rotational crossbreeding scheme; if it also incorporates terminal crossbreeding, it is then called a rotaterminal system. By mating the crossbreed with a third breed, hybrid vigor may be further enhanced. [2]

Heterosis, hybrid vigor, or outbreeding enhancement, is the improved or increased function of any biological quality in a hybrid offspring. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of its parents. These effects can be due to Mendelian or non-Mendelian inheritance.

See also

Purebreds, also called purebreeds, are cultivated varieties or cultivars of an animal species, achieved through the process of selective breeding. When the lineage of a purebred animal is recorded, that animal is said to be pedigreed.

Selective breeding Process by which humans use animal and plant breeding to selectively develop particular phenotypic traits

Selective breeding is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together. Domesticated animals are known as breeds, normally bred by a professional breeder, while domesticated plants are known as varieties, cultigens, or cultivars. Two purebred animals of different breeds produce a crossbreed, and crossbred plants are called hybrids. Flowers, vegetables and fruit-trees may be bred by amateurs and commercial or non-commercial professionals: major crops are usually the provenance of the professionals.

Related Research Articles

Canchim cattle breed

The Canchim breed is a breed of beef cattle developed in Central Brazil by crossing European Charolais cattle with Indubrazil cattle already kept in Brazil where Asian Zebu type cattle are best suited to the tropical conditions. When compared with Zebu bulls, Canchim bulls produce the same number of calves, but heavier and of superior quality. Compared to European breeds, the Canchim bull produces calves with the same weight but in larger numbers. The fast-growing progeny, from crossbred zebu cows with Canchim bulls, can be slaughtered at 18 months old from feedlots after weaning, up to 24 months old from feedlots after grazing and at 30 months from grazing on the range.

Beefalo cattle breed

Beefalo, also referred to as cattalo or the Canadian hybrid, are a fertile hybrid offspring of domestic cattle, usually a male in managed breeding programs, and the American bison, usually a female in managed breeding programs. The breed was created to combine the characteristics of both animals for beef production.

Dog crossbreed dog type

Crossbreed dogs or designer dogs are dogs which have been intentionally bred from two or more recognized dog breeds and not from dogs with no purebred ancestors, but have not been artificially bred to each other enough to breed true and be recognized as a breed in their own right.

Crossbreed hybrid

A crossbreed is an organism with purebred parents of two different breeds, varieties, or populations. Crossbreeding, sometimes called "designer crossbreeding", is the process of breeding such an organism, often with the intention to create offspring that share the traits of both parent lineages, or producing an organism with hybrid vigor. While crossbreeding is used to maintain health and viability of organisms, irresponsible crossbreeding can also produce organisms of inferior quality or dilute a purebred gene pool to the point of extinction of a given breed of organism.

Poodle crossbreed dog crossbreed

Poodle crossbreeds or poodle hybrids are the offspring of purebred poodles that have been crossbred with another purebred dog breed. They may be described as a mixed breed dog, designer dog or, sometimes, as a hybrid dog.

Eurohound Dog breed

A Eurohound is a type of dog bred for sled dog racing. The Eurohound is typically crossbred from the Alaskan husky group and any of a number of pointing breeds ("pointers").

In agriculture and in the hobby of animal fancy, a breeder is an individual animal used for selective breeding. Usually a breeder is a purebred animal bred with the intent of producing purebred or even show-quality animals. However, in some cases, a breeding animal is crossbred with another breed or a mixed breed with the intent of combining aspects of two or more different breeds.

Animal breeding is a branch of animal science that addresses the evaluation of the genetic value of livestock. Selecting for breeding animals with superior EBV in growth rate, egg, meat, milk, or wool production, or with other desirable traits has revolutionized livestock production throughout the world. The scientific theory of animal breeding incorporates population genetics, quantitative genetics, statistics, and recently molecular genomics and is based on the pioneering work of Sewall Wright, Jay Lush, and Charles Henderson.

Spanish goat goat breed

The Spanish goat, also called the brush goat or scrub goat, came originally from Spain via Mexico to the USA. It is now a meat and brush-clearing type found widely in the United States. In the Southeast and elsewhere, they are often referred to as "wood" (Florida), "brush" or "briar", "hill" (Virginia), and "scrub" goats. Until recently, these goats were kept mainly for clearing brush and other undesirable plant species from pasture lands.The boer goats have overtaken Spanish goats for meat in the 1980s.

Sex-link

Sex-links are crossbred chickens whose color at hatching is differentiated by sex, thus making chick sexing an easier process. Sex-links come in several varieties. As hybrids of laying or dual-purpose breeds infused with extra vigor via heterosis, sex-links can be extremely good egg-layers which often produce 300 eggs a year or more depending on the quality of care and feed. The color of their eggs vary according to the mix of breeds, and blue-green eggs are possible.

Grade horse horse of mixed breeds

A grade horse is a horse whose parentage is unknown, unidentifiable, or of significantly mixed breeding. This differs from purebred animals of known bloodlines and also differs from deliberately crossbred animals that are produced with an intent of either creating a new breed of horse or an animal with characteristics that deliberately combine the strengths of two different breeds. Many grade horses are the result of unintentional or accidental breedings, though in some cases, they are the result of a planned breeding of a stallion and a mare, but animals who themselves are of uncertain bloodlines.

Black Hereford (crossbreed)

The Black Hereford is a crossbreed of beef cattle produced in the British Isles with Hereford beef bulls with Holstein-Friesian dairy cows. Black Herefords are not usually maintained from generation to generation, but are constantly produced as a byproduct of dairy farming as a terminal cross. They are one of the most common types of beef cattle in the British Isles, outnumbering many pure beef breeds.

Friesian Sporthorse type of Frisian cross, bred specifically for sport horse disciplines

The Friesian Sporthorse is a Friesian crossbred of sport horse type. The ideal Friesian Sporthorse is specifically bred to excel in FEI-recognized sport horse disciplines. Thus, "sporthorse" refers to the phenotype, breeding, and intended use of these horses.

Purebred dog

A purebred dog typically refers to a dog of a modern dog breed with a documented pedigree in a stud book and may be registered with a breed club that may also be part of a national kennel club.

The Comeback is a type of domestic sheep originating in Australia. This type of sheep results from crossbreds produced by British Longwool sheep and Merinos being mated back to Merinos. This cross is made to achieve a finer, better style of wool. Comeback style wool is also produced by Bond, Cormo and Polwarth sheep and they may prove easier to breed than Comebacks. The Comeback sheep are raised for meat and their fine wool.

The Black Hereford is a beef cattle breed, derived mainly from Hereford cattle, but with some mixture from black Angus cattle, resulting in black cattle with a white head and finching.


Purebred breeders are dog breeders that intentionally breed purebred dogs specifically to continue the lineage of certain breed characteristics in dogs by mating selected canines.

Designer crossbreed

A designer crossbreed or designer breed is a crossbred animal that has purebred parents, usually registered with a breed registry, but from two different breeds. These animals are the result of a deliberate decision to create a specific crossbred animal. Less often, the animal may have more than two pure breeds in its ancestry, but unlike a mutt or a mongrel, its entire pedigree is known to descend from specific known animals. While the term is best-known when applied to certain dog crossbreeds, other animals such as cattle, horses, birds and cats may also be bred in this fashion. Some crossbred breeders start a freestanding breed registry to record designer crossbreds, other crossbreds may be included in an "appendix" to an existing purebred registry. either form of registration may be the first step in recording and tracking pedigrees in order to develop a new breed.

References

  1. Terminal and Rotaterminal Crossbreeding Systems for Pork Producers University of Missouri, Columbia Mo.
  2. Should Replacement Gilts be Raised or Purchased? North Carolina state university, North Carolina