BREED VALUE ESTIMATION

 

Peter van Oirschot (SV) Holland.

 

What do you wish to achieve with the progeny from your females? Is it possible to achieve this goal by hereditary? Which male in this case is most suitable for my female.

 

Every breeder should ask themselves these questions.

 

It also must be remembered that not all of the qualities of both parents will be seen in the same amount with the children.

In principle counts for hereditary properties that the expectation for his/her progeny increases/decreases as:

 

(a) The amount of relatives with the same characteristic is either high or low.

(b) The relationship (hereditary of similarity) of dogs with the characteristic is high or low.

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In principal every characteristic of a dog is measurable. In how far the rating is influenced by hereditary is different per characteristic and even per animal. It is in the interest of breeders that they should know in advance, how big the changes are that the progeny will develop a certain characteristic.

 

The way hereditary properties do influence the characteristic is variable. The characteristic per animal;

 

(a) Is partly determined by genes but can also be influenced by environment and living circumstances.

(b) Can be determined by one gene (monogene) or by many genes together (polygene).

 

A dog can look well but the question is, are the genes also well? Further to that, what within that total breed is the expectation for the progeny. Above we have spoken about characteristic;which can be characteristics of the exterior and the behaviour, but also the presence or absence of a disease is also a characteristic from a dog.

 

 

 

What is Breed value estimation.

 

Since its beginning in Germany in 1988, it is now very common to do breed value estimations within many breeds. There is now good cooperation between these and also from abroad. International databases are now widely available.

There are some very good examples of how breed value estimations are made, nad more importantly did that particular breed make progress from that point. The other side of the coin is that breed value estimation on its own is not the correct solution. It is useless to know how many calories there are in a cake if you are not prepared to change your eating habits.

The breed value estimation is a measurement tool useful for breeding. It describes the effects of genes upon a characteristic at the moment those genes are combined with the genes of other animals within the same breed under the influence of similar environment conditions.

 

Breed value estimation and itís three important points.

 

(1)                             Breed value estimation is a measured value. This measured value has nothing to do with usefulness or uselessness. A high measured value for hip dysplasia means that the genes cause high degrees of hip dysplasia. A high measured value for wither height means that the height is increased.

(2)                             Breed value estimation is a measured value for only one characteristic. A dog has genes which can improve growth, genes that can reduce hip dysplasia, or genes that make some dogs better trackers than others. It is no use to make a summation of all these characteristics in one dog and then calculate the average of it, like we do at exams or contests.

(3)                             We define the breed value of genes at the moment they are being combined with the genes of other animals of that particular breed. That is why it is of no importance how the genes manifest themselves in the animal itself, but more importantly what happens when a hereditary property of a particular male is being combined with different females. So what happens by using that male in the next generation.

 

 

How do we get the information?

 

One of the problems in breeding is that you cannot see the genotype of a dog only the phenotype, which is influenced by nutrition, experience (training) and environment.It would be a big mistake to identify one dogs performance with his genetic aptitude.

Because of the inheritance of genes and the fact that half comes from the male and the other half comes from the female, it is useful to get the performances of the paents into the evaluation. The parent not only gives their genetic aptitude to that one particular dog but also to other progeny (brothers and sisters).After a whiel the influence ot the proceedings of those genes will be observable in all these animals. Finally the heredity aptitude of the progeny is the most important: above or under the average? There will be a larger progeny after some time and by that the breed value of a particular breeding dog becomes obvious.

In this way all relatives participate in the inheritance of that particular animal and thereby all become very valuable for the information for that animals breed value.

The significance of that information depends on how strongly the dogs are related.

(a)     Parents are 0.5 related to their children because the children become 50% of the inheritance of their parents.

(b)     Grand children are 0.25 related to their grand parents.

(c)     Half brothers/sisters do have 25% of their genes common.

 

Because an animal itself is related 100% to itself the information of his/her own performances is also very important.

Without further explanations of the computer calculation models used for combining al this information, it is obvious that all this information together is of more importance than only the information of the animal himself.

The relatives do not become 100% of the inheritance, but 0.5 or 0.25 or 0.125 etc. All together this information makes the other influences (like environment) become average. This also counts for influences by other genes, so that the whole becomes a breed typical representative.

Never again will so much information be available. This enables us to give a 100% breed value. That is why it is called a breed value estimation.

By the breed value of the parents we can get an idea of what can be present in their progeny. Because the puppies become a coincidental half of the parents by fortune or misfortune the brothers and sisters can be rather different. By means of the characteristics of those puppies we can increase the estimation of the breed value. For example, we will use the height of the withers. The male we use has a breed value of+0.5 and the female has a breed value of +1.5. We expect out of this combination, puppies with genes for +1 centimetre and thereby the average will be 1 centimetre higher than the breeds average height. This does not mean that al the puppies will have the same height. Because of half the inheritance one puppy can have the more positive genes and another can have lesser positive genes. All this can be checked by measurement. The smaller animals will have a lower breed value for the wither height than the larger oneís.

It can be assumed that the hereditary aptitude for these differences is also responsible for the fact that the smaller animals out of that litter will inherit smaller than their larger siblings. But again by environmental influences differences in height may also occur.

In practise we do not use absolute numbers but we convert them into relative numbers. The average breed number used is 100, and hereby the breed value is transformed, so the average may differ 10 points above or below. What we see is that a dog with 100 is average of inheritance. You can compare the numbers for characteristics and convert them, especially when weknow that they move between 70 and 130.

 

Registration of breed value estimation.

 

If one decides to do breed value estimation for one characteristic the result will be that there will be a breed value estimation for every animal of that breed. It does not have to be examined or evaluated because every animal has a lot of relatives that already have been evaluated by which the breed value can be derived. For example a females breed value for cryptorchism can be found by assessing her male progeny. This is also how the breed value for the production of milk by certain bulls is calculated.

For many breeds 6 characteristics are taken into research by means of breed value estimation. These are characteristics of great value or in which problems occur within that particular breed. The registration of these breed values are available fro the breeding committee and in some organisations, say SV, they are also available for the breeders. The breed associations do have the responsibility to the new owners of puppies that their expectations are guaranteed. They expect an original specimen of the breed with the breedís special qualities and with a good health. The breed association is in fact responsible that puppies are bred with a high quality standard. For the characteristic HD this means that we should have puppies to a HD degree lower thanthe average in the breed.

Because of half the inheritance from the sire and dam the breed value of the puppies may not be higher than the breed value of the respective parents. So if we want to use a female with a breed value of 106 she can only be mated to a male that has a lower rating, in this case lower than 94. This kind of rule has already shown a great progression in other breeds. It has also been proven that this only works when the breed association is enforcing these rules. When this responsibility has been given to the breeders themselves it has been proven that the progress stops or even declines.

In many breeds breed value estimation has already become the norm and with that the interest in breeding dogs has increased. Luckily those breeders have also shown that they not only breed with breed values (ratings), but still breed with dogs.

A passionate breeder needs more information for his creative work than breed values alone.

He has to look at Breed Surveys, exams and the progeny that already exist.

Only those kind of successful breeders will survive.

 

Reprinted with the kind permission of the author.