What Are the Effects of Inbreeding Dogs?

Researchers have been studying the effects of inbreeding in dogs for many years. As with humans and other species, inbreeding has the ability to produce severe problems in one dog or an entire breed. Inbreeding occurs when closely related dogs are bred, sometimes by accident and sometimes by pure ignorance of the potential problems.

  1. Genetic Health Problems and Disease

    • Inbred dogs are at higher risk for certain genetic diseases. When closely related dogs are bred, each may have a recessive gene (only having one copy of the defected gene) for any given genetic disease. The recessive gene may be passed onto the new generation. Once the new generation carrying the recessive gene is bred with a related dog carrying the same recessive gene, the gene manifests and is displayed in the produced puppies, according to a study conducted by researchers at Imperial College London.

      Common genetic diseases include epilepsy, hip dysplasia and glaucoma. Deafness, blindness and other conditions may also manifest as a result of inbreeding.

    Shallower Gene Pools

    • Inbreeding is not always purposeful. In some cases, the gene pools of the breeds are slowly diminished because of having a small original breeding stock in a country. For example, prior to 1987, the gene pool of the basenjis in America was based on 12 original dogs--seven studs and five bitches. This resulted in the gene pool being diminished over the course of three to four decades. In the late 1980s, a project was started to bring the native African dogs to America to replenish the gene pool.

      Although the basenji breed is a prime example, the occurrence is not limited to this breed. The occurrence is also not limited to complete breed lines. The American Kennel Club's breeding standard is to breed for the "betterment of the breed." This, in essence, means breeding only the studs and bitches with all the health, appearance and temperament qualities of the breed standard. Because of this desire to produce top-quality pets and show dogs, one stud or bitch may produce so many litters that the gene pool of "top quality" dogs gets reduced and the recessive, undesirable genes get passed on and become dominant.

    Birth Defects

    • Inbreeding may also produce several birth defects. The breeding of closely related dogs affects the mutation of genes during fetal development. Birth defects may include additional or missing limbs or organs that never fully developed properly. Inbreeding also increases neonatal and fetal death along with the risk of birth defects, according to an article written by veterinarian Bretaigne Jones for Royal Canin.