Breeding value estimation

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Under genetic evaluation (CFB) comprises various standardized method in animal breeding the genotype of an individual based on the phenotype to assess this individual and his family and him by environmental factors induced modifications to delimit.

Action

The breeding value describes what effect the genes of an animal have on a single phenotype trait when these are combined with the genes of other animals and average environmental conditions prevail. A breeding value of 100 describes an average inheritance of the assessed trait, higher breeding values ​​stand for an inheritance in which the trait is strengthened, lower breeding values ​​for a weakening of the trait. If one compares the breeding value of an animal with the average breeding value of the entire population, it becomes clear whether this animal should be used in breeding and which breeding value is tolerable in its potential partners.

A material used for genetic evaluation statistical method is the best linear unbiasedness prediction , shortly Blev ( English Best Linear Unbiased Prediction shortly BLUP ). It is mathematically complex and involves the solution of systems of equations with hundreds of unknowns.

In principle, the procedure is that to determine the breeding value of an individual:

  • The phenotype of the individual
  • The phenotype of its parents
  • The phenotype of its full and half siblings
  • The phenotype of his offspring

A number can be calculated from these phenotypes using BLEV, which is called the breeding value.

Ideally, the breeding value is calculated from the phenotypes of the animal and its family according to the list above. The calculation method used allows a breeding value to be determined even if there is no complete information on the phenotype of all relevant individuals. In extreme cases, it is also possible to estimate a breeding value without knowing the phenotype of the animal whose breeding value is being estimated.

From this approach it is also clear that the breeding value of an individual can change as soon as new information on phenotypes becomes available for himself and his relatives.

Breeding value estimates can also be used when the phenotype under consideration follows a complex inheritance and can be influenced by the environment. The phenotype should have the highest possible heritability .

Horses

In warmblood sport horses, the breeding value estimation is used to select sport successes . The aim is to be able to assess the breeding value of young stallions as early as possible . The genetic value estimates for warmblood stallions are summarized in so-called stallion lists .

Two different breeding values ​​are estimated for German riding horse breeding: the breeding value estimation for young horse tests and the breeding value estimation for competition sport . The breeding value estimation of young horses is more influenced by the disposition of the offspring. In the case of the breeding value estimation of tournament sport, on the other hand, greater weight is placed on the training and performance of the horse. So it is less influenced by inheritance. In return, more results flow into the breeding value assessment of tournament sport because more tests take place. The estimation model for both breeding value estimates is a BLEV animal model that is based on several characteristics.

Breeding value estimation young horse test

The breeding value estimation of young horse tests is determined from the results of advanced tests for young horses (e.g. show jumping tests , young dressage horses ), broodmare tests , disposition tests and stallion performance tests in the individual associations. Around 4.4 million results from corresponding tests were available for this in 2018.

The marks used are the marks for walk, trot, canter, rideability and free jumping (for broodmare and disposition tests) as well as the marks for gaits, rideability, free jumping and jumping over the course (for stallion performance tests).

Breeding value estimation of tournament sport

For the breeding value estimation of tournament sport, the results of all registered sport horses are evaluated in Germany . For example, around 550,000 sport horses were registered with the FN in 2018 . In 2018, for example, the FN registered over 17.8 million results from tournament sport competitions in Germany, of which 12.3 million results from jumping competitions and 5.4 million results from dressage competitions .

Genetic assessments tournament sports with a confidence level of at least 70% will be released when the concerned stallion have at least five offspring with own work in the estimate and a published breeding value Young Horse Test has.

Farm animals

In the case of farm animals, breeding value estimation is mainly used in the selection for performance characteristics. In farm animals it is used to select fertility , milk yield and meat gain.

In the honey bee, honey yield, gentleness, honeycomb fit, swarm tendency and Varroa index are included in the breeding value.

Pets

In dogs, breeding value estimation is particularly widespread in the fight against polygenic hereditary diseases , such as hip dysplasia , elbow dysplasia and various eye diseases such as Collie Eye Anomaly .

literature

  • Horst Kräusslich (Hrsg.), Gottfried Brem (Hrsg.): Animal breeding and general agricultural teaching for veterinarians. Enke, 1997, ISBN 3-432-26621-9 .
  • Christian Fürst, Jörg Dodenhoff, Christa Egger-Danner, Reiner Emmerling, Henning Hamann, Dieter Krogmeier and Hermann Schwarzenbacher: Breeding value estimation for cattle - basics, methods and interpretations , 2015 ( online as pdf )

Individual evidence

  1. ↑ Reiner Beuing: Breeding value estimation in dog breeding (pdf; 67 kB)
  2. ↑ FN-Zuchtwertschaetzung_2018.pdf , FN
  3. ↑ FN breeding value estimation 2018 , November 24, 2018, fn-press
  4. ↑ State Institute for Apiculture Hohen Neuendorf: Breeding value results for selected queens