The Australian Shepherd is a healthy breed compared to many but is not without hereditary problems. Hip Dysplasia and several different eye defects are the most common problems in the breed.
Hip Dysplasia (HD) is found in all dog breeds and is basically bad development of the hip joints. This disease is not caused by a single pair of genes, but instead is "polygenic". This means many gene pairs determine the condition and development of the hip joints. This has made the disease extremely difficult to understand and to determine the genetic inheritance involved.
It has been found that the incidence of HD can be lessened by careful selection of breeding stock. Australian Shepherd breeders have been leaders in the control of the disease in this breed.
Why is HD such a concern? Lameness varying from slight to very severe crippling can occur, usually between six months to a year or in the dogs older years. Some dogs never show lameness at all but have the disease. These dogs can run and jump but carry the disease and can pass it on to their offspring.
HD can only be diagnosed with x-rays taken by a competent veterinarian after the dog is past it's second birthday. The Orthopedic Foundation for Animals (OFA) has for many years served as the diagnostic expert for this disease. X-rays submitted to the OFA are sent to three independent radiologists for a consensus opinion. OFA will not certify a dog free from HD until it is two years old. Dogs may be x-rayed for a preliminary evaluation earlier than two years, but because of the progressive nature of the disease, OFA will not certify them until two years of age.
Most recent statistics from OFA report an incidence of 6.5% of Aussies with HD from 9,712 evaluated. This sounds like a small percentage, but it is about 1 out of 15 which would be one in every two litters. This statistic comes from dogs owned by conscientious breeders and owners who use the OFA, and not the general population so this may be deceiving.
To be a conscientious breeder, breed only OFA certified individuals and guarantee pups to be free from HD. Littermates and siblings are also important. An animal diagnosed as having HD should never be bred.
For further information and applications to submit x-rays you can write to the OFA. They also have a booklet available for a $3.00 donation:
Orthopedic Foundation for Animals
2300 Nifong Blvd.
Columbia, MO 65201
The Aussie also can be affected by eye defects with varying degrees of hereditability. Progressive Retinal Atrophy (PRA) is a very serious disease which is caused by a recessive gene. The end result is complete blindness. We do know that affected dogs inherit the gene from both parents, so both parents are carriers. All the puppies from an affected dog will have the disease or be carriers. This disease may not show up until later in the dog's life which is a reason for yearly eye exams by a veterinary ophthalmologist.
A regular veterinarian can not diagnose most eye diseases. When a dog is examined by a veterinary ophthalmologist and diagnosed free of disease the owner will receive a form. The owner can submit this form to CERF to receive a number declaring the dog free from eye defects. If CERF is not used, the owner should be able to provide a copy of the ophthalmologist forms to potential buyers.
Another eye defect diagnosed in the Australian Shepherd is Collie Eye Anomaly (CEA) which is also hereditary. Again a veterinary ophthalmologist needs to check the eyes of all dogs used for breeding.
A defect that can be seen without special equipment is the Iris Coloboma, and it is especially noticeable in blue eyes. The inheritance of this defect has not been identified although studies have shown it occurring in families. In these eyes the pupil appears to extend into the iris (colored part of the eye) often with a jagged edge. The ASCA breed standard calls for the pupil to be well defined and perfectly positioned. If the pupil is not perfectly round and in the center of the eye, the eye is not normal. Most dogs with an Iris Coloboma appear to function normally, but there is evidence that this is inherited and affected dogs should not be bred.
Juvenile cataracts are a serious defect as they also end in blindness. This is a disease and different than old age or senile cataracts. Again a veterinary ophthalmologist would need to diagnose the disease in its early stages.
Other inherited diseases have been observed in the Australian Shepherd to a lesser degree. ASCA strongly recommends that all puppies be sold with a guarantee against hereditary defects and all breeding stock be OFA Certified and have a clear eye check.