Many diseases from which our dogs suffer are inherited conditions that are either passed directly to them from their parents, or are common in their breeding lines. Most of these diseases are more frequently seen in pedigree dogs, but mixed-breed pets can suffer from them as well.
Abnormal joint conformation is a highly inheritable problem and often leads to early-onset arthritis. The most commonly affected joints are elbows and hips. Pre-breeding screening programs are in place for the most vulnerable pedigrees, which include the Labrador Retriever, Golden Retriever, German Shepherd, and Rottweiler. The American Kennel Club (AKC) keeps a list of which breeds should be tested for abnormal joint conformation before mating on its website.
The most commonly inherited heart diseases in dogs are abnormal heart valves and enlarged hearts. Abnormal heart valves, or valve dysplasia (especially tricuspid valve dysplasia) are especially common in smaller breeds of dog, particularly the Cavalier King Charles Spaniel. This condition is also found in the Bull Terrier, Irish Terrier, and Sussex Spaniel. The problem with valvular disease is that a heart murmur, the main warning symptom, doesn’t generally appear until middle age, which is usually well after the affected dog has been bred.
An enlarged heart, or Dilated Cardiomyopathy (DCM), develops usually in large breeds of dog, such as the Golden Retriever, Doberman Pinscher, Boxer, and Great Dane. Again, this disease doesn't generally occur until middle age and the symptoms can be extremely subtle, making diagnosis a challenge. Unfortunately, in many cases, pet parents are unaware that there is a problem until their dog suddenly suffers from a heart attack. Even if DCM is caught before such an attack, it is usually well established and difficult to treat.
Retinal disorders and glaucoma are two of the most frequently diagnosed eye conditions that our dogs can inherit. Both will lead to blindness, but screening programs exist in the most affected pedigree breeds to try to remove dogs with these conditions from the bloodlines.
Inherited retinal disorders generally fall into two categories:
- Dysplasia, where the cells of the retina do not form properly, affects many Terrier breeds, such as the Soft-Coated Wheaten Terrier, Airedale Terrier, and West Highland White Terrier, as well as the Beagle, Chinese Shar Pei, and Australian Cattle Dog.
- Atrophy; where the cells gradually die away over time, is found in the Belgian Malinois, Border Collie, Dachshund, Papillon, and the Lhasa Apso.
These retinal cells are responsible for processing and filtering the light from the environment and sending the information to the brain, so if these cells fail, the affected dog will be unable to see. There is no cure.
Glaucoma is the result of increased pressure in the lens of the eye, which causes damage to the optic nerve. It can occur in various ways, some of which are heritable conditions affecting the Akita, Boston Terrier, Chihuahua, and Poodle, among other breeds. It is an extremely painful condition and will eventually result in blindness. Treatment is available, but can be challenging.
Some forms of cancer are very much more common in certain breeds of dog. For example, bone cancer, or Osteosarcoma, is almost exclusively seen in large and giant breeds, including the Saint Bernard, Irish Setter, and Greyhound. Golden Retrievers suffer more with Hemangiosarcoma, a cancer of the blood system that often develops tumors on the spleen. Bull breeds, especially Boxers, as well as English Bulldogs, Basset Hounds, Pugs, and Weimaraners, are vulnerable to Mastocytoma, or Mast Cell Tumors, found in the skin and respiratory tract, and Flat-Coated Retrievers are notorious for suffering from cancers of all kinds.
If your pet belongs to any of these breeds, it is wise to be vigilant for the relevant symptoms and changes associated with cancer. New and innovative treatments for canine cancer are continuously being developed to help our furry companions.
Many screening programs are in place for pedigree dogs to try to reduce the incidence of health issues. If you are planning to purchase a pedigree puppy, you should research the problems within the breed and ensure that the breeder has carried out the relevant testing.
Of course, you cannot guarantee that your dog won't suffer any problems, even if the proper screening programs are in place, or if you adopt a crossbreed. You can, however, take certain responsible steps, such as meeting the puppy's parents and questioning the breeder closely on their health, before you commit to buying any new dog.