Health and Genetics

Aussie Health & Genetics – Overview

Canine Geneticists estimate that the average “normal” dog carries 4-5 defective genes.  Each dog inherits 50 % of its genetic payload from each parent. Most genetic diseases that affect quality of life tend to be polygenic ( which means several genes are involved )
The Australian Shepherd, although generally known as a healthy breed has several “late onsetting” problems that can show up well after they are adults.

Epilepsy and Cataracts are listed at the top of the Breed’s health concerns.  To understand about genetics and breeding strategies visit that has compiled noted authors in these subjects.

Australian Shepherd Health and Genetics keeps up to date information on current health studies and articles of interest on their website. (

The CNASA encourages everyone in the Aussie Fancy whether a Breeder or companion owner to participate in any current Health studies for our Breed to ensure we can safe-keep the Aussie for future generations to enjoy.

Articles of Interest

The list of articles below will be changed and/or added to as new submissions are received.

If you click on the names of the articles they will all open in new windows – just close the window to return to this page…

The Latest News

DNA tests now available for 2 eye diseases in the Aussie breed.

Progressive Retinal Atrophy (PRA) has recently been identified in the Australian Shepherds.

Optigen ( announces that a DNA-based test is now available for a form of PRA (refers to a group of diseases that cause the retina of the eye to degenerate slowly over time).

This genetic disorder causes rod and cone cells in the retina at the back of the eye to degenerate and die, even though the cells seem to develop normally early in life. The result is declining vision and eventual blindness. The rod cells operate in low light levels and are the first to lose normal function. Then the cone cells gradually lose their normal function in full light situations. Typically, the clinical disease is recognized first in early adolescence or early adulthood.

Also available at Optigen is the test for the recessive eye disorder Collie Eye Anomaly (CEA) / Choroidal Hypoplasia (CH).

Since the choroid layer does not develop normally from the start, the primary abnormality can be diagnosed at a very young age. The ophthalmologist, looking at the back of the eye (the fundus) with an ophthalmoscope, typically will see an area of choroidal thinning that appears like a “window” to the underlying vessels and sclera.

The affected dog is homozygous recessive – that is, both copies of the gene are mutant. All affected dogs, regardless of the actual severity of the lesions, are homozygous for the same mutant gene. (A dog with one mutant copy and one normal copy of the CEA/CH gene is a carrier – is heterozygous. A dog with two copies of the normal CEA/CH gene is homozygous normal.)

This genetic test can distinguish all three genetic states – normal, carrier and affected. With this information, the breeder can plan matings that avoid producing any affected dogs by always selecting one parent that is normal. The other parent can be normal, carrier or even affected, and no affected dogs will result.