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An insight into Breeding – which is important for all!

Dog breeding means practice of mating selected dogs with intention to produce particular qualities and characteristics in offspring. However, this selective breeding has also led to a rise in various diseases.

 

Selective breeding…
Selective breeding or close breeding, commonly known as line breeding or inbreeding, results that the number of bad genes in most breeds

exceeds the average number which significantly reduces the genetic variables involved in mating two individual dogs and thereby increases the Coefficient of Inbreeding (COI) which alters the natural defense mechanism of body and finally may lead to various disease manifestations.

Coefficient of Inbreeding (COI)…
This is a mathematical tool that provides a measure of the degree of relatedness of the individuals in any given dog’s pedigree. It is an approximation and not an absolute measure. Individuals with low COIs (less inbred) are more likely to have two different MHC (Major Histocompatabilty Complex) haplotypes. Every individual has a pair of MHC haplotypes which are inherited from each parent.

The immune system…

Dr. MK Singh

Dr. MK Singh

The immune system is governed by the MHC. This cluster of genes is referred to as a ‘complex’ because of their close positioning on one chromosome. This positioning virtually enables it to be inherited as a unit called a

haplotype. MHC enables the immune system to respond precisely against invading infectious agents like bacteria or viruses. It exists in all species of mammals and not only unique to dogs. MHC genes are exceptionally polymorphic, each having many—sometimes as many as 100—different alleles or forms. MHC complexity is an excellent example of the importance of biological diversity—not only among species but also within them. All naturally reproducing species will avoid or significantly limit inbreeding.

Prone to infections…
Inbred individuals are always homozygous in relation to their MHC genes (i.e. the two sets of identical haplotypes received from parent). This situation diminishes the diversity among MHC and thus body’s capability to mount an effective immune response. Such dogs are more prone to infections and are more likely to suffer autoimmune disease or allergies.
Use of popular sires over several generations can play havoc with MHC diversity. Since any individual can only have two MHC haplotypes, if a significant portion of a breed descends from a relative few number of dogs, the whole population may be threatened. Furthermore, this may lead to poor or ineffective utilisation of vaccines.

Consequences of bad breeding in dogs

  • Skin problems
  • Immune system disease
  • Narrow immune response
  • Vaccine inefficacy
  • Blood disorders
  • Neurological, behavioural and sensory
  • Hearing and vision
  • Heart disease
  • Cancer
  • Orthopaedic
  • Affecting other vital organs and systems

Things to note

  • Close breeding must be discouraged by breeders.
  • Avoid the over-use of any individual dog, no matter how fine a specimen he might be.
  • No dog affected with chronic autoimmune disease or serious allergies should be bred.
  • Breeders should be aware of their dogs’ Coefficient of Inbreeding (COIs).
  • Crosses that produce autoimmune disease or allergies should always be discouraged.
  • Recording much information as possible on the allergy and autoimmune disease status of numerous relatives of the dogs.
  • If screening tests are available for a disease, it should always be used before breeding.

Saving – up to us!
The storm is upon us and we can get rid of it. The potential impact of close breeding on dog’s health is enormously great. Even though we are currently unable to eliminate this kind of problem, damage control must be properly instituted. With good record keeping, diligence and foresight the risk of
producing these costly, potentially devastating, and sometimes-fatal affections can be significantly reduced.
(Dr MK Singh is scientist in Immunology Section at Indian Veterinary Research Institute, Izatnagar, UP).

Breeding myths busted!

When it comes to breeding, a lot of myths surround it. Here are a few of them.

Myth: Breeding a flighty female dog will steady her temperament.

Fact: There is no evidence of this at all. A female-dog with unstable temperament may actually become more 017agitated when her protective instincts regarding her litter come into play. Moreover, the dam of a litter does imprint her character on her offspring. An unstable female-dog should not be bred.

Myth: Any dog carrying an undesirable gene should be neutered.

Fact: It depends on what the undesirable gene is. Every dog has some undesirable gene(s) whether they are expressed or not. Genes that affect the health and quality of life of the offspring should obviously be avoided, but it is important to know what the genetic history of the dog is not just the dog himself.

Myth: Repeat litters are never as good as the first ones.

Fact: There is no evidence that this is true. Each breeding is a combination of the genes of two dogs and different traits may be expressed, especially in an outcross pairing.

Myth: Bully breeds are not safe to adopt or rescue because of unknown genetic history. They attack more humans than any other dog.

Fact: There are quite a few Pitbull variations and they are a prolific and popular breed. They are bred to be territorial and protective. Although many bullies are sweet, some are aggressive. I don’t think there are statistics to support this statement, but the breed should be understood and properly kept.

The genetic history is less important with adoptions and rescues than knowing if the dog has a bite history with other dogs or humans.

Myth: Purebreds are ‘weaker’ than mutts.

Fact: When dogs are inbred, the deleterious genes become more concentrated and are therefore more likely to be expressed in the offspring. Obviously “mutts” are not inbred but they can also inherit undesirable genes. Purebreds can and should be healthy when bred by responsible breeders.

Myth: Genetic means congenital.

Fact: Congenital means a condition that exists at birth. A congenital defect may be an anomaly that results from developmental issues during the growth of a foetus and may not occur in siblings or other offspring. When a number of puppies have a congenital defect, then a genetic cause should be considered.

(Himmat Singh Sekhon runs Saras Tibetan Mastiffs kennel based in Amritsar, Punjab. The kennel was established in 1983 with exclusive interest in the breed)