Health Conditions and Genetic Conditions Affecting Mini and Toy Aussies

Miniature Australian Shepherds (and Toys) are succeptable to certain genetic issues the same as their full size counterpart. We take all necessarry percautions by testing our adult dogs and basing our mating pair decisions off these results. By not crossing two carriers of the same disease, choosing clear (non carrier) puppies to keep back for our next generations, we preserve this wonderful breed while reducing the potential for health issues. Below you will find information reguarding the most common genetic issues and how our program is designed to avoid them- giving you pease of mind that your new pet will live a long and healthy life!

Common Conditions Tested

• PRA
• HC
• MDR1
• CD
• Hips
• Elbows

Information in this section is brought to you by the Australian Shepherd Health & Genetics Institute

Progressive retinal atrophy – (PRA) any of several diseases characterized by the gradual degeneration of the retina.  When discussing PRA it is important to know which type is under discussion as they are caused by different genes and, in at least one case (Centralized PRA) is due to nutritional imbalance.

Cone Degneration (CD) – a retinal disease causing day-blindness in puppies.  CD can be diatnosed by eight to twelve weeks of age.  There is a DNA test available.  The disease appears to have a recessive mode of inheritance, so both parents of an affected dog will be carriers.  Affected dogs should not be bred.  Carriers may be bred to clear-tested dogs.

Collie Eye Anomaly (CEA) is a sometimes blinding congenital inherited eye disease.  All dogs with CEA have bilateral choroidal hypoplasia (CH), also called chorioretinal dysplasia, a thinning of the vascular tissue in the back of the eye which does not significantly impair vision.  Some dogs will also have optic nerve coloboma, in which the nerve tissue is not fully developed where the optic nerve enters the back of the eye.  A few will have retinal detachment.  Both of these more serious defects can be blinding.  CEA is present at birth and does not progress, so there is no worry that an affected puppy will get worse as it gets older.  It also does not cause the affected puppy any pain.

Multi-Drug Resistance 1(MDR1)-  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.

               Which drugs cause MDR1 reactions?

Ivermectin was the first drug recognized to cause a reaction, but it is far from the only one.  Ivermectin at low dosage, as found in heartworm medications, will not cause a reaction.  The larger doses needed for worming will.  Other commonly administered drugs on the list include acepromazine and Imodium.  Fortunately, there are alternative medications available if your dog requires treatment.

The drugs involved can be found on the VCPL website.

Common Definitions-

Heritability –  that portion of a trait which can be inherited (Example: Hip dysplasia is not 100% heritable because environmental conditions can affect its expression), also the degree of variation which can be influenced by heredity. (Example: All Schipperkes are black and black color is inherited, but the heritability of black in Schipperkes is 0% because they are all homozygous for the trait and there is no variation.)

Ten Steps to a Healthier Australian Shepherd Breed- (link)

1. I recognize that genetic disease is a longstanding fact in the Australian Shepherd breed. Only through open and honest communication and sharing of accurate information can we, the breeders and guardians of this breed, improve the overall genetic health and significantly reduce the incidence of genetic diseases in the breed we love. 
2. I support the open disclosure of all health issues that affect the Australian Shepherd, utilizing publicly accessible canine health registries in the country of my residence whenever possible.
3. I openly and publicly disclose all information in my possession about the health issues that have been produced by my dogs and dogs from my breeding, and also those health issues where a significant risk factor may exist.
4. If I receive information about a new genetic issue in connection with my dogs or breeding, I work to the best of my ability to notify the purchasers/owners of dogs that are related to the dog with the new issue.
5. I support and assist other breeders in their disclosure efforts.
6. I do not speak ill of any breeder or breeding program that has produced an affected Australian Shepherd.
7. I compassionately support and assist owners of affected dogs in the gathering of information on the genetic diseases that have stricken their dogs.
8. I support research studies for genetic diseases in Australian Shepherds, submitting biological samples from dogs in my kennel or of my breeding when they are available and applicable for the study. I encourage others to do the same.
9. Before being bred, all of my dogs are DNA profiled with an accredited laboratory and the results made public, if such services are available within my country, or before my stock is exported to a country that has DNA profiling available.
10. I will have my dogs screened for genetic diseases, as recommended on the ASHGI web site, by veterinarians who have the proper certification. I support the recording of test results in open registries and as they become available to me, I will post my results. As new genetic tests for Australian Shepherds become available, I will submit my breeding stock for those tests.