Byline: Kansas State University
MANHATTAN, Kan., April 12 (AScribe Newswire) -- While you may love the size and facial features of your toy poodle, these characteristics are at the root of many health problems small, purebred dogs face.
Veterinarians at Kansas State University's College of Veterinary Medicine say many health problems that arise with small-breed dogs are present because the dogs are bred to be very small with infantile features. The two most noticeable problem areas are orthopedics and heart.
Dogs considered 'small breed' generally weigh less than 20 pounds. Typical breeds include the toy poodle, Lhasa apso, Pekingese, chihuahua and dachshund, among others.
Dr. James Roush, professor of clinical sciences at K-State's College of Veterinary Medicine, said two orthopedic problems commonly seen in small-breed dogs are patella luxation and Legg-Calve-Perthes disease.
In patella luxation, Roush said the knee cap sits on the inside or outside of the leg rather than the front. He said this is a hereditary problem that requires surgical treatment. Roush said the problem develops very early in small-breed dogs. Symptoms of patella luxation are lameness, 'skip' walking, crooked back legs and a popping sensation when the knee moves, as well as the inability to straighten knees.
Legg-Calve-Perthes disease is an autosomal-recessive inherited disease of the hip. This means that if both parents are carriers, the puppy has a 25 percent chance of having the disease.
The disease occurs when the dog is around 1 year old and leads to arthritis. Symptoms include lameness, reluctance to rise, play or jump into a vehicle and resistance to agility training.
Roush said owners can choose to treat the disease with surgery or pain medication after arthritis sets in.
Dr. Barret Bulmer, assistant professor of cardiology at K-State's College of Veterinary Medicine, said small-breed dogs are over-represented in the development of degenerative valvular heart disease.
He said that, as the heart valves undergo degenerative changes, they are no longer able to prevent the 'backward' flow of blood. If this insufficiency is severe enough, fluid may begin to accumulate in the lungs, outside the lungs or within the abdomen.
The first indication of a problem is often the presence of a heart murmur detected during a pet's annual veterinary evaluation. Bulmer said it is difficult to predict which dogs will eventually develop heart failure or how quickly the valvular disease will progress. Therefore, most pets with degenerative valve disease require periodic ECGs, chest X-rays and cardiac ultrasounds to follow their disease progression and determine when medical therapy is needed.
Bulmer said the cause of degenerative valve disease is unknown but is believed to be an imbalance in collagen formation and breakdown.
'Our current medical therapy is aimed at alleviating the signs of heart failure via the administration of diuretics, ACE inhibitors, digoxin and several other drug classes,' Bulmer said. 'Many owners have encountered these exact same drugs when a family member has been treated for heart disease. Investigations into the potential for heart valve replacement/repair and the potential for stopping or delaying the degenerative valvular process represent areas of research throughout the veterinary community.'
Owners of big dogs should be aware of special health concerns for large, purebred canines.
K-State veterinarians said two concern areas for large-breed dogs are orthopedic and heart problems.
Roush said these issues arise because large-breed dogs are bred to be the biggest and grow the fastest.
'You don't see these problems in mixed-breed or wild dogs,' Roush said.
Dogs considered 'large breed' generally weigh more than 60 pounds. Typical breeds include the Saint Bernard, Newfoundland, Great Dane, Labrador retriever and German shepherd dog, among others.
To help prevent orthopedic problems, veterinarians recommend that owners feed large-breed puppies a special dog food, usually called large-breed dog food. Roush said this is recommended because growth rates are different in large breeds.
He said large breeds are prone to many diseases that depend on how fast the dogs grow, which is primarily determined by the calcium intake and energy levels they receive from food. Large-breed dog foods are formulated to control these aspects of growth.
Roush said the orthopedic problems that most commonly affect large-breed dogs are hip dysplasia, elbow dysplasia, osteochondritis dissecans, hypertrophic osteodystrophy and cervical vertebral instability, also known as wobbler's disease.
The symptoms are similar for many orthopedic problems in large-breed dogs, and include lameness, reluctance to rise, play or jump into a vehicle and resistance to agility training. Treatment typically involves surgery or arthritis medication.
Hip dysplasia is a result of a poor fit in the hip joint that leads to arthritis. Elbow dysplasia is a syndrome comprised of three diseases that can be treated separately -- osteochondritis dissecans, ununited anconeal process and fragmented coronoid process.
Osteochondritis dissecans is a defect of joint cartilage in a major joint, usually the shoulder, knee, elbow or 'ankle' or between vertebrae. Roush said the condition primarily affects young dogs.
Hypertrophic osteodystrophy is an abnormal bone growth leading to pain at the ends of bones. Like osteochondritis dissecans, Roush said a dog suffering from hypertrophic osteodystrophy is usually young. The dog may not want to walk much and may have visible swellings that are painful and/or warm to the touch.
Cervical vertebral instability is caused by a malformation of the cervical vertebrae that causes instability between two vertebrae, usually in the neck. Roush said the condition is often referred to as wobbler's disease by veterinarians because a dog suffering from it will appear 'drunk' and 'wobbly.' Wobbler's disease leads to neurological disease and eventually paralysis.
Roush said large-breed dogs can be certified as free of orthopedic problems by the Orthopedic Foundation for Animals at 2 years of age.
Bulmer said the most frequent cardiac condition that affects large-breed dogs is a form of heart muscle disease called dilated cardiomyopathy.
Bulmer said dilated cardiomyopathy is a condition in which the heart cannot contract sufficiently to propel blood forward to vital organs and exercising muscles. Symptoms may vary from subtle exercise intolerance and lack of appetite to more severe signs like coughing and fainting episodes, as well as fluid accumulation. Rarely, dogs may experience sudden death without previous symptoms.
Bulmer said the cause of dilated cardiomyopathy is unknown but could be a combination of genetic, inflammatory, viral, environmental and nutritional influences. Although it is incurable, veterinarians can treat the symptoms of dilated cardiomyopathy and improve a dog's survival and quality of life.
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CONTACTS: Dr. Barret Bulmer, (000)-000-0000, bbulmer@vet.k-state.edu
Dr. James Roush, (000)-000-0000, roushjk@vet.k-state.edu; http://www.mediarelations.k-state.edu/WEB/News/MediaGuide/jroushbio.html; Pronouncer: Roush is ROWSH
