Mini and Toy Australian Shepherd Health Page

Health concerns and your new Aussie.

While in general Aussies are a very hardy breed there are a couple of health issues that are Aussie specific and we would like to do our part to make all future Aussie owners aware of them. 

 NEVER PRESCRIBE IVERMECTIN TO ANY  AUSTRALIAN SHEPHERD
Ivermectin Sensitivity. Some Australian Shepherds and Miniature Australian Shepherds are highly sensitive to Ivermectin, available both as a single worming treatment and in a lower dosage as a heartworm preventive under the brand name Heartguard®. Ivermectin affects the central nervous system in individuals to which it is toxic. Symptoms of Ivermectin toxicity include depression, excitability, seizures, loss of muscle control, drooling, coma or even death. Interceptor® is a non-Ivermectin based heartworm treatment safer for most Miniature Australian Shepherds. Sentinel® combines
Interceptor® and Program® into one pill.

Breeding Merle to Merle
Basically what all this is saying is that don't buy a dog from a merle to merle breeding.  Ever!!!!  Responsible and knowledgeable breeders do not do this.  In fact I will go a step further and say if the breeder is doing merle to merle breeding I wouldn't buy a dog from them even from their non merle to merle breedings.  If they don't know enough to avoid this they probably shouldn't be breeding Aussies. 

 Pretty much the first paragraph says it all.  The health problems created by this combination are often hidden until you fall in love and are many thousands of dollars into the health care of a "pretty" yet unhealthy dog. 

While Aussies may be best known for their unusual merle coloring, the incomplete dominant gene which produces the pattern is semi-lethal. When a dog inherits two alleles for merling, which can happen only when a merle is bred to a merle, the resulting puppies
are often predominantly white, deaf and/or blind and often develop other less immediately noticeable problems, including organ failure and auto-immune disorders. Merle to merle breeding should only be undertaken with great care by those breeders who understand the consequences and are willing to make the difficult decision to cull puppies exhibiting undesirable traits. One breeder saved one apparently normal puppy from a merle to merle breeding but which at the age of 4 months began exhibiting unusually aggressive behavior. The puppy was later identified to have certain underdeveloped organs, causing it great pain and the choice was made to humanely euthanize the puppy.
Each Miniature Australian Shepherd carries two alleles for merling; one allele each is inherited from each parent. The alleles are represented "M", for merling, or "m" for solid. Therefore, a mini Aussie can be genotypically MM (phenotypically an excessive white
dog, a.k.a. homozygous merle, double merle, lethal white, lethal merle), Mm (heterozygous or single merle) or mm (solid).

A merle to merle cross will require that, on average  25% of the puppies be euthanized at birth, as the merling gene is connected with disorders of eyes, ears and other internal organs. The exact cause is unknown, but one current theory suggests that the lack of melatonin interferes with the correct development of organs situated directly beneath the under pigmented areas. Each merling allele inhibits more pigmentation from the solid coat pattern. Therefore, a dog which has two alleles for merling may completely lack pigmentation, especially around the head. Because of the correlated defects, "excessive white" is a disqualifying fault according to the ASCA Breed Standard.