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Hip Dysplasia is a condition that affects the lame-femoral joint, also called the hip. This joint is formed by the femoral head and acetabular cavity of pelvis bones, and is responsible for the transmission of forces of the spine by the Member subsequent to the ground when the animal walk or run.
For this to function properly it is necessary that there is a perfect contact of the two bone surfaces (round the head of the femur and the acetabulum concave), but also resistance of surrounding soft tissues such as the joint capsule, round ligament (the head of the femur to the acetabulum, as the joint capsule), muscles and tendons surrounding the joint.
What is hip dysplasia?
Hip Dysplasia is a condition of biomechanics of development, that is, the animal is born normal but during their first months of life the hip joints suffer change in its shape due to lack of contact between the bone surfaces causing deformation of head of femur. The lack of joint congruity leads to osteoarthritis which in many cases is responsible for pain and consequent lameness.
The lack of congruence of bone joint surfaces due to a faster maturation process of the skeleton in relation to soft tissue (muscles, joint capsule, ligaments) which causes there to be ennui (lack of resistance) and consequently failure to maintain regular contact between the bone surfaces of the joint.
This lack of resistance of the soft tissue surrounding the joint leads early articular sub-luxação (head of the femur is badly seated in acetabular cavity) and later injuries to arthritis.
What causes hip dysplasia?
Hip Dysplasia is an inherited disease and genetics, although some environmental factors may contribute to an increased expression of the disease in animals with genes for hip dysplasia.
For the development of the disease, the animal has genes for hip dysplasia. No one knows for sure how many genes are involved, but it is known that there are many, so it is called poligénica disease. In poligénicas diseases the higher is the number of altered genes inherited from parents more marked is the disease in dogs. However, the question is not as simple as some of the genes combine randomly and not addictive, although a very small number.
Environmental factors such as being overweight, hydroxyglutarate ration growth curve very sharp, slippery and smooth, excess minerals such as calcium, over-exercising, contribute to exacerbating the changes but they are not the cause of the disease.
The hip dysplasia appears with equal prevalence in all races?
Hip Dysplasia is a disorder that appears most often in medium and large dog breeds, although it can occur in any breed.
The races are more prone for example s. Bernardo, Bulldog, Newfoundland, Labrador Retriever, Golden Retriever, Mastiff, German Shepherd, Serra da Estrela, Rafeiro do Alentejo, Shar-Pei, Akita, Setters, Swiss Banks Dog, Rottweiler, Dobermann, etc.
The small breeds are also affected although by their body weight in many cases not showing clinical signs of disease.
What is the importance of x-raying my animal?
There is no genetic test to lose an animal carrying genes for hip dysplasia. The radiographic examination, it is nowadays considered the means of diagnosis which best allows you to throw the animals not having clinical signs of hip dysplasia have however injuries consistent with the disease, being these injuries a marker for the presence of genes for the disease.
The animals should be x-rayed to 12 months for medium and large breeds and 18 months giant breeds. The Rottweiler being a large breed should be x-rayed to 18 months. From 5-6 years of age the assessment becomes more difficult since there may be no arthrosis lesions related to hip dysplasia. Therefore, for the purposes of screening of hip dysplasia should avoid submitting radiographs of
animals from this age.
Why anesthetize the animal to accomplish radiographic examination?
General anesthesia allows a full muscle relaxation and that way we can correctly position the animal for the exam. Otherwise we will have to repeat several times the radiograph until a rx of good quality. Without a correct positioning is impossible to assign a rating to the film. On the other hand the muscle relaxation allows to observe the joint laxity with greater ease and thus be more accurate the evaluation.
What is the meaning of the different degrees of classification of hip dysplasia?
The degrees awarded in classification of hip dysplasia in Portugal are the degrees defined by the breed Club International Federation and who identify themselves by letters: A, B, C, D, E.
The degrees A and B are animals without radiographic signs of hip dysplasia, the degrees C, D, e and match animals with signs of hip dysplasia. The grade C corresponds to mild Dysplasia, moderate dysplasia degree D and the degree and severe dysplasia.
What are the degrees of hip dysplasia that can use in reproduction?
In principle we should use in breeding animals with grades A and B, in fact that would make it possible to reduce significantly the number of genes for dysplasia. However, in some breeds, hip dysplasia level is so high that if you eliminate all animals with grade C we'd be with a set of very limited players. In these cases you can use a parent with degree C while the other must be A or b. This is an exception should not be the rule.
What is the importance of reducing the prevalence of the disease?
If we use in breeding animals with hip dysplasia perpetuates disease with increasing intensity due to the effect of the additive combination of the mostly genes and therefore animals with more marked signs. This has repercussions for the suffering of individual animal involved and its owners, the higher expense associated with therapy and often loss of animals with excellent characteristics in terms of beauty or work. On the other hand, in terms of a race inevitably leads to backsliding in terms of characteristics of the breed and a much larger effort later to obtain animals without signs of hip dysplasia.
What is the importance of knowing the degrees of Dysplasia in animals presents a pedigree?
The recognition of the degree of dysplasia until the 3rd or 4th generation of a pedigree is very important because it gives us the perception of the probability of occurrence of animals with hip dysplasia.
If I have a dog classed as grade B from parents and grandparents with grades A and B this animal probably will have very few genes for hip dysplasia. If on the contrary I use a player (male or female) with grade B but with some of the forefathers with grade C and D the probability to get dogs with hip dysplasia is frankly bigger.
The inscription of the degrees of Dysplasia in pedigrees and their analysis is a key helper in the careful selection of the reproducers.