We start this article first by defining the word inbreeding.
Inbreeding is the production of offspring by parents more closely related than the population average. Genetically, consanguinity increases the share of homozygous genes in the consanguineous population.
Line breeding is a form of inbreeding in which an attempt is made to concentrate the inheritance of an ancestor or the line of an ancestor in a herd.
It is a great pleasure for me to share a topic with those interested in defining this topic of dog breeding. As a geneticist and master breeder, I am presenting this article because a lot of people in the dog business are raising dogs and you always hear the comment “Oh, he has a blood family.” Well, I am sharing this article with you so that before you comment, at least you know what the words mean and how they can be used in a positive way to help the breed we love so much, the Jack Russell breed!
Inbreeding is a mating system in which progeny are produced by more closely related parents than the average population from which they come. Example A: the mating of a father with his daughter
Example B: the mating of a full brother with a full sister.
These procedures are avoided because past experience has shown that inbreeding is often associated with the appearance of genetic defects and a general decrease in vigor and performance.
In human beings, it is believed that the children of the marriage of first cousins are doomed to be deformed physically or mentally, and this belief is the reason why we have laws to prohibit the marriage of close relatives.
The genetic effect of inbreeding is that it makes more pairs of genes in the population homozygous regardless of the type of genetic action involved. All the phenotypic effects of inbreeding are the result of this single genetic effect.
Inbred animals are generally less able to cope with their environment than non-inbred animals. This is demonstrated by their ability to reproduce and litter size decreases along with a slower growth rate and small body size at maturity. You will also see a weakening in the immune system that will cause further illness and disease within these consanguineous individuals. Some of the other negative effects that Jack Russell breeders really need to look at is the jaw line, how the teeth line up in our puppies and by which the families and the individual we use can identify the progeny with any other defects early .
Now we turn to the subject of genetic improvement and its benefits. Line breeding is a form of inbreeding in which you try to concentrate the inheritance of an ancestor, or a line of ancestors and it is usually a male rather than a female because a male generally produces many more offspring than a female. Line breeding is generally a mild form of inbreeding that is directed towards an ancestor that often involves the mating of half siblings. It can also be used as closely as a grandfather – granddaughter or uncle – niece mating. Again, you will increase the genetic traits of the father you want to use. I believe this method will be beneficial in helping to understand the definition and its use in any breeding program. But again, we must always strive to produce a structurally correct and genetically sound short-legged Jack Russell Terrier that we can all be proud of.
For example, some of the traits to avoid when mating our short-legged Jack Russell Terrier are excessive back length and poor quality legs that are not straight and healthy. We always prefer a dog whose ear fits over your head and folds down, not upright. Again we must monitor the jaw line to see if there are bites above and below. We must also take into account the depth of body capacity and the opening of its rib cage, after all, this is where the puppies will be taken. Again, you want a dog that has a wide base width when viewed from behind. This also affects the birthing process. And again, you want a prominent vulva in your females because the more correct we do to our dogs, the longer their reproductive lifespan will be and their overall health will improve. Again, this will ensure that you and your client have a puppy that you will both be proud of!