Behavioural problems caused or exaggerated by inbreeding can range from low IQ and difficulty in training to spontaneous aggression. Intelligence deficit. Aggression. Fearful and timid temperament.
Inbreeding two closely related dogs can cause malfunctioning organs, cosmetic defects, and other abnormalities. While some congenital disabilities are manageable, others pose lifelong trouble for the dog. Many pedigree dogs born with any flaw are considered defective, so they won't be eligible for registration.
The highest level of inbreeding by far (> 80%) is for the Norwegian Lundehund. This breed suffers from extremely low fertility and high puppy mortality as well as an often lethal gastrointestinal disorder.
Behavioural problems caused or exaggerated by inbreeding can range from low IQ and difficulty in training to spontaneous aggression. Intelligence deficit. Aggression. Fearful and timid temperament.
Other negative effects of inbreeding documented include decreased immune system function, decreased viability, decreased reproductive ability and the loss of genetic diversity (i.e. decrease in genetic variation). Collectively, these adverse effects of inbreeding are known as inbreeding depression.
The most obvious effects of inbreeding are poorer reproductive efficiency including higher mortality rates, lower growth rates and a higher frequency of hereditary abnormalities. This has been shown by numerous studies with cattle, horses, sheep, swine and laboratory animals.
They found that on average, the more inbred an animal was (using its “true COI” measurement), the smaller the litter size. The least inbred dogs had an average litter size of 8 puppies, while the most inbred dogs had an average litter size of 6-7 puppies.
So it shouldn't really be a surprise that the breed has accumulated a few genetic inconveniences along the way. Bull terriers are also prone to breathing problems, heart and kidney disease, deafness, and knee issues. Purebred dogs are all inbred because, well, that's what it means to be a purebred dog.
You need to keep the original sire and dam, too. Breed three generations of female puppies back to your original sire. This concentrates the blood. This is called line breeding since you are breeding in a line back to the original sire.
Inbreeding refers to the mating of close relatives in species that are normally outbreeding. Matings between father and daughter, brother and sister, or first cousins are examples of inbreeding.
The European Union Responsible Dog Breeding Guidelines and the Dog Breeding Reform Group state that breeders should avoid breeding from individual dogs whose combined coefficient of inbreeding (the combination of both parents), measured over at least 10 generations, is greater than 6.5% [5].
Not all dog breeds are alike in terms of health, however. Tamaskan Dogs, Barbets, Australian Labradoodles, Danish-Swedish Farmdogs, Mudis, and Koolies were some of the least inbred, and they had rates of vet care comparable to mixed-breed dogs.
Inbreeding levels of 5-10% will have modest detrimental effects on the offspring. Inbreeding levels above 10% will have significant effects not just on the quality of the offspring, but there will also be detrimental effects on the breed. Do I still have to worry about COI if I am doing the health tests for my breed?
On most occasions, it is generally considered dangerous to breed brother and sister dogs together because of the risk of long term health complications. Even if inbreeding is carefully planned and managed, it still has the potential to cause other indirect problems over time.
How big their parents are. Generally speaking, puppies inherit their size from their parents. If you know how big mom and dad are, you'll have a good idea of how big your puppy will be. This is a good place to start if you're trying to estimate your puppy's future size.
The effect on longevity was not strong but caused higher mortality for men above one year of age. The risk of stillbirths showed a substantial association with inbreeding, with a higher risk for highly inbred. The probability of having children was lower for persons representing high levels of inbreeding.
Inbreeding means mating father to daughter, mother to son, and brother to sister. Line breeding involves mating more-distantly related animals, although there is a conventional wisdom that says line breeding is whatever works and inbreeding is whatever doesn't.
The negative aspects of inbreeding involve poor reproductive efficiency, high mortality rates, low growth rates, and a high frequency of hereditary abnormalities.
Inbreeding is a double-edged sword. On the one hand a certain amount of inbreeding can fix and improve type to produce excellent quality animals. On the other hand, excessive inbreeding can limit the gene pool so that the breed loses vigor.
Some dog breeds are more inbred than others because breeders select for specific traits based on how it makes a dog look. For example, smaller dog breeds like Shih Tzus and pugs are bred to have extremely short snouts—often, to the point where they appear flat-faced.
Results suggested that wild dogs avoided mating with kin. Inbreeding was rare in natal packs, after reproductive vacancies, and between sibling cohorts (observed on 0.8%, 12.5%, and 3.8% of occasions, respectively).