Australian Shepherds, along with several other, mostly collie-type breeds, can carry a genetic mutation that makes them sensitive to certain drugs. Use of those drugs can cause serious neurological illness or even death. Fortunately, there is a DNA test that will let you know whether your dog has this mutation. All of our dogs have been tested(Normal/Negative) or clear by parentage for the mutation.
What is MDR1?
MDR1 is the abbreviated name of a gene called Multi-Drug Resistance 1. A mutation of this gene causes sensitivity to Ivermectin and a number of other drugs. Dogs with the mutation will react to those drugs. Whether a dog reacts depends on the dosage of the drug. A dog may not react to very low doses, as with the amount of Ivermectin found in heart worm products. Typical doses of a variety of medications will cause reactions in dogs with two copies of the mutation, but some drugs – most notably several chemotherapy agents – can cause reactions in dogs with only one. Dogs with this mutation have a transport defect—the drug goes in to their brains, fails to be transported out, and builds up to toxic levels. This causes serious neurological problems including seizures and sometimes death.
There are several genetically distinct forms of Progressive
Retinal Atrophy in dogs. PRA is a
gradual degeneration of the retinal tissue. The form found in Australian Shepherds is Progressive Rod Cone
Degeneration (PRCD). Age of onset is
usually in the prime of life. The first
things an owner might notice is night-blindness. T disease progresses, over months or years, until the dog is blind. The disease is caused by a recessive gene mutation.
Since PRCD is progressive, it may require multiple exams before diagnosis can be confirmed. PRAs can be misdiagnosed. Any Aussie diagnosed with PRA should also have the PRCD DNA test to confirm the diagnosis. Affected dogs should not be bred. Carriers should be bred only to mates that have tested clear and all offspring which will be used for breeding will need to be tested. Preference should be given to non-carrier offspring. Carriers should not be used at public stud.
To get a dog certified with OFA, an x-ray is taken of the hips and elbows and sent to OFA (Orthopedic Foundation For Animals). There it is evaluated and given a grade of excellent, good, or fair; these are all passing scores. They could also receive a score of (mild, dysplastic or severely dysplastic). While this doesn't show if a dog may carry the genes to produce hip problems, it shows the dog itself has normal hip structure. By testing our breeding dogs, we do all we can to lower the chances that puppies may inherit hip or elbow defects.