breed

from Wikipedia, the free encyclopedia

When breeding in is Biology controlled reproduction with the aim of genetic referred forming. Desired properties should be strengthened and undesired properties should be made to disappear through appropriate selection. In order to achieve the goals, a breeding value assessment is carried out either by the breeder himself or by a breeding association (for example after a variety test ) in order to then select specifically individuals with the desired characteristics (artificial selection ) and to cross or mate with one another based on a crossing plan . Knowledge of Mendel's theory of inheritance is an essential prerequisite . However, mutations can also be triggered artificially or organisms can be genetically modified . New plant varieties and animal breeds are as new varieties called, they are subject to legal provisions.

Conventional breeding methods of crossing and mating are limited in their possibilities of gene combination, since particularly in animals, fertile reproduction among alien individuals is severely restricted (see mule ). In order to overcome this species-specific limitation, genetic engineering is used, the process of which is controversial.

Word origin and meaning

The word corresponds to the Middle High German zühter (Old High German zuhtari ) and originally means teacher or educator . This meaning is still partly contained in today's word chaste (decent).

The term cattle breeding is only applicable if the breeding selection and the pursuit of breeding objectives influence reproduction. In the early agricultural societies, however, this was not the case, which is why animal husbandry is used in prehistory and early history . Almost all societies are familiar with the domestication of animals and controlled reproduction .

Legal definition

In Austria there is the following definition of breeding in Section 4 of the Federal Act on the Protection of Animals (Tierschutzgesetz-TSchG):

"Breeding: human-controlled reproduction of animals by keeping sexually mature animals of different sexes together, targeted mating or raising a specific animal for breeding or by using other techniques of reproductive medicine."

history

In parallel with the at least seasonal settling down of humans, individuals were selected in both plants and animals in which desirable traits were most pronounced. These beneficial individuals should reproduce as useful specimens ( selection breeding ).

In the systematics of taxonomy established by Carl von Linné (1753) , forms with changed properties that have arisen through selection are designated as subspecies . Today in zoology one speaks of races and in botany of sorts and varieties or, more generally, of clans .

The beginning of a selective selection of parent animals is commonly associated with the British Robert Bakewell (1725–1795). Because of the improvements he was able to achieve in British cattle breeds, his British contemporaries called him the "Great Improver". The evolutionary theory of Charles Darwin (1859) posits a natural selection as the basic mechanism of evolutionary process over geologically long periods to the emergence of new types of leads ( speciation ). Critics of the theory of evolution and advocates of species constancy reject the possibility of the emergence of new species through (artificial or natural) selection and therefore distinguish between microevolution as a variation within a species and the macroevolution they contest as a species- forming process.

Gregor Mendel's (1869) research results with peas have revolutionized breeding; not the mixture of “bloodlines”, but genes that are inherited dominantly or recessively are the “building blocks of life”. The principles of inheritance he formulated are still valid today.

In the natural environment plays bastardization (hybridization) in the plant world an important role, but in animals it is rare artbildend. The history of mankind and its breeding efforts have left little traces in this regard - only a few of the oldest cultivated plants and domestic animals are now listed as independent taxons . In the process, the wild form was often displaced and became extinct or even merged into the cultivated form, so that a clear distinction is not possible. Examples are:

The domestic dog Canis lupus familiaris, for example, has been shown to be a close subspecies of the wolf , other proportions are likely to be only marginal; however, the rewilded dingo Canis lupus dingo is also listed as a separate subspecies. The house cat is an undefined hybrid complex of the various natural subspecies of the wild cat Felis silvestris , presumably primarily the black cat .

aims

Industrial animal breeding

The aim of the breeding of animal breeds is the optimal utilization of the animals as suppliers of products. There are different approaches: Either animals are bred in classic breeding through targeted selection and mating , thereby making progress in breeding . Or are hybrid animals in the hybrid breeding (see: hybrid chicken , Hybridpute , Hybrid pigs , hybrid honey bees ) bred. You cannot continue to breed with animals from hybrid breeding, as these hybrids are from inbred lines and the properties of the hybrid animals are lost when they are crossed with one another. This is based on the respective breeding goals.

Farm animal breeding

Some animals are bred for human use, such as horses , mules , donkeys, or fighting bulls .

Small animal breeding

In addition, there are hobby breeders (including small animal breeders) who mainly focus on dogs, cats, rabbits and guinea pigs , reptiles , fish and a number of bird species, for example chickens , pigeons ( pigeon breeding ), large parrots , parakeets , songbirds and birds of prey . In the breeding of small animals, only pedigree and ornamental poultry are bred. Pet birds such as parrots or ornamental birds such as representatives of the soft-eaters fall under parrot or aviculture.

Excesses here are so-called torture breeding , that is, the promotion of characteristics that are detrimental to the health of the individual, in order to make the visual appearance more distinctive in most cases. Torture breeding is prohibited in Germany under the Animal Welfare Act.

As a hobby breeding according to the German Animal Welfare Act z. B. to consider a breeding of budgies from 25 breeding pairs as commercial. Everything that is below is officially classified as hobby breeding.

Conservation breeding

Species that are threatened with extinction are mainly bred in the zoological gardens . These include in particular exotic species.

In the last two decades, with the growing interest in bioversity, conservation breeding of endangered livestock breeds has also developed, often in the form of breeding rings .

Image breeding

The attempt to purposefully “back-breed” the typical wild animal characteristics of extinct species from domestic animals that have emerged from them is called image breeding. The former large grazing animals of Europe - aurochs and wild horses - which, according to the mega-herbivore theory, played a decisive role in the preservation of open landscapes in the otherwise forested Central Europe of the more recent post-ice age, are particularly popular here . One tries to achieve this role, among other things, through the use of suitable breeding images - such as Heck cattle and Heck horse - for nature conservation projects with the goal of process protection / wilderness development area.

Breeding process

Plant breeding

Breeding methods for different plant species depend on the type of reproduction, category and type of variety; Examples:

  • Self-fertilization (fertilized by one's own pollen); Line breeding (population with defined characteristics, the persistence of which is retained by selection); Line types; Wheat , barley .
  • Cross fertilization (pollen from other individuals); Population breeding (reproductive communities which are not identical in their hereditary constitution, but can be crossed); Open-pollinated varieties; Rye , grass.
  • Vegetative fertilization; (Progeny by cell division from somatic tissue of the mother plant); Clone breeding; (Carried out exclusively vegetative propagation); Clone variety; Potato .
  • Controlled fertilization (artificial process, for targeted crossing); Hybrid breeding (pollination control for maximum control of fertilization); Hybrid; Corn , sugar beet.
  • Other breeding methods are: embryo transfer , genetic engineering and smart breeding .

Animal breeding

There are basically five types of breeding strategies for farm animals.

Pure breeding

In pure breeding, animals of the same breed are paired with one another . The breed represents a so-called pure breed population .

Grafting

Occasionally, animals of other races are crossed into pure-bred populations , in particular animals of the races from which the breeding originally started. This process is known as graft breeding or graft crossing (outdated: blood refreshment ). The breed standard is achieved through (artificial) selection within the breed.

Displacement breeding

In the displacement breeding or crossbreeding (also English. Upgrading ) are in a race again animals crossed a second race, a feature of the second race the gene pool add to the initial population. The result of a displacement crossing is a new pure-bred population ( see above ) with a new characteristic.

Rotational crossing

In rotational crossbreeding, a number of purebred breeds are paired one after the other according to a fixed system - and mostly the female offspring after selection are used again for breeding. Two- and three-race rotational crosses are usually carried out. This means, if the three breeds A, B, C are used (three-breed rotation crossbreeding): Animals of breed A are crossed with animals of breed B, the cross-offspring AxB with breed C. The offspring of this three-breed crossbreed (AxB) xC are again crossed with animals of breed A and so on. The crossing leads to heterosis effects , which means that the products of a rotational crossing have better functional properties than the parent animals. Also in the case of rotary crossbreeding, the selection takes place according to characteristics in the pure breeds and through the selection of suitable crossbreeds. Furthermore, the animals that are used for rotational crossing are also selected. Rotary crossbreeding is only rarely used, but is particularly important in cattle farming.

Crossroads of use

When crossbreeding is used, animals of different pure breeds are crossed with each other. One also knows here different forms, z. B. Two-race crossbreed, three-race crossbreed, four-race crossbreed. The decisive factor here is that the end cross product is no longer bred, but only used, e.g. B. for milk or meat production. The crossing leads to heterosis effects, as a result of which the products of a usage cross have better usage properties than the parent animals. However, the heterosis effect is greater than with a rotational crossing.

The selection according to characteristics takes place in the case of utility crosses in the purebred populations and through the selection of suitable cross breeds.

Hybrid breeding is a special form of crossbreeding . Hybrid breeding creates pure lines that in many cases are heavily inbred . These pure lines are crossed with each other. Due to the strong selection during the breeding of the lines, the heterosis effects at the crossing can be predicted or increased much better.

Strictly speaking, the use cross is not a breeding process for a farm animal because the product of the use cross is no longer used for breeding.

If the crossbred animals are paired with each other, the next generation splits up in their characteristics according to the Mendelian rules . If the characteristics of the hybrids are stabilized by crossing each other, one speaks of the creation of a new breed.

Examples of the breeding methods

There are different breeding methods, for example outcrossing , selection breeding, inbreeding , line breeding . Most of the useful breeds are purebred. Examples of pure breeding in animals are the English thoroughbred and the thoroughbred Arabian , which do not tolerate any further crossbreeding. Most of the other breeds exceptionally allow crossbreeding of foreign breeds to improve properties, e.g. B. Simmental from Red-Holstein . The transition from the graft cross to the displacement cross can be fluid (e.g. emergence of the German Holstein population).

The crossbreeding is used with all farm animals in order to produce high quality animals. In cattle breeding , the pure-bred populations are kept by the individual breeders and, if necessary, crossed with other breeds. This is particularly the case in dairy cow husbandry (e.g. Brown Swiss , Jersey cattle ) or suckler cow husbandry for the production of animals suitable for fattening. Crossbreeds are also common in pig breeding . The races Pietrain are often used as father (good fattening performance) and German landrace as mother (good fertility, mother characteristics). The piglets resulting from this pairing (crossbreed piglets, sometimes also referred to as hybrid piglets) are only used for fattening.

The crossbreeding in the special form of hybrid breeding is mainly used in pig breeding and poultry breeding . Pure lines are bred as basic populations (similar to pure breeding) and very strongly selected. The different basic populations are crossed with one another to produce the farm animals. The basic populations in pig breeding, for example, are kept by breeding companies (basic breeding companies, e.g. JSR Hybrid Hirschmann, Schaumann, PIC, BHZP, SZV (Pig Breeding Association Baden-Württemberg)). The animals from the crossing of two basic populations but also animals of the basic population themselves are z. B. sold to "multiplication farms". The breeding farms produce gilts for the piglet producers. The piglets are finally generated by the pig producers, these show (by artificial insemination or natural mating ) sows (female line) with boars of other breeds / lines or intersections in accordance with the system of the hybrid breeding program. After 21 to 27 days, the hybrid piglets are weaned (= weaned). With about 30 kg live weight, the animals are now called runners, they are sold to the fattener . The fattening farm now fattening the animals up to a weight of around 100 kg until slaughter . The division of tasks between the basic breeding farm, the multiplier farm and the piglet producer can also vary and is called a separate or division of labor system.

The continuation of the breeding of crossbred animals - the so-called offspring - was z. B. used in the creation of most animal breeds. A recent example is the breeding of the German riding pony .

criticism

Plant breeding and agricultural livestock breeding are largely undisputed.

In relation to humans, the concept of breeding is linked to that of eugenics and racial hygiene . The state control of human reproduction in the sense of breeding is forbidden in most countries today by corresponding freedom rights . Representatives of the animal rights movement suggest that certain animals should be given this status on the basis of imputed basic rights.

Animal welfare-relevant consequences of dog breeding were criticized in the film Pedigree Dogs Exposed , among others . Among other things, the fact that dog shows increasingly select for appearance rather than functionality, that pedigree dog breeding leads to increased inbreeding depression and that some of the characteristics required in the breed standard are directly linked to suffering in the dog ( torture breeding ) are criticized .

See also

literature

  • Manfred G. Raupp: The Debate Concerning the Effects on Bioinformatics on Food Production ; Sciencia Agriculturae Bohemica 32, Czech University Prague-Suchdol 2001 CS ISSN  1211-3174
  • Helmut Hemmer: Neumühle-Riswicker deer - first planned breeding of a new form of livestock . Naturwissenschaftliche Rundschau 58 (5), pp. 255-261 (2005), ISSN  0028-1050

Institutions

Official German institutions

Advocacy groups

Web links

Individual evidence

  1. ↑ Grain growers are researching ever better varieties. Retrieved April 5, 2016.
  2. ↑ Amendment to the Animal Welfare Act, Federal Law Gazette I No. 35/2008
  3. ^ Philip Walling: Counting Sheep - A Celebration of the Pastoral Heritage of Britain . Profile Books, London 2014, ISBN 978-1-84765-803-6 . P. 43
  4. ^ Animal Welfare Act: Hobby breeding . In: Federal Republic of Germany (Ed.): Administrative regulation for the Animal Welfare Act . No. 12.2.1.5.1 . Berlin January 2015.
  5. ↑ In the Brockhaus encyclopedia from 1996 it says under the corresponding lemma: “ Blood refreshment, animal breeding: outdated description for the crossing of breeding animals from the area of ​​origin with animals in the breeding area. "[Emphasis on the Wiki author]
  6. Jump up blood . In: Heinrich August Pierer , Julius Löbe (Hrsg.): Universal Lexicon of the Present and the Past . 4th edition. tape 14 . Altenburg 1862, p. 827 ( zeno.org ).
  7. ^ Entry "Offspring" in the online dictionary , accessed on March 1, 2018.
  8. ^ Arnd Krüger : A Horse Breeder's Perspective. Scientific Racism in Germany. 1870-1933. In: Norbert Finzsch , Dietmar Schirmer (Ed.): Identity and Intolerance. Nationalism, Racism, and Xenophobia in Germany and the United States. University Press Cambridge, Cambridge 1998, ISBN 0-521-59158-9 , pp. 371-396.
  9. ↑ Jean-Claude Wolf : Arguments for and against animal law , March 2008
  10. ↑ Bundessortenamt - home page. Retrieved January 2, 2019 .
  11. ↑ http://www.jki.bund.de/
  12. ↑ http://www.fli.bund.de/
  13. ↑ http://www.bdp-online.de/
  14. ↑ http://www.zds-bonn.de/
  15. ↑ http://www.bdf-web.de/