The Australian Cattle Dog like most breeds
have hereditary and congenital problems which the new
owner should be aware exist and should discuss with the
breeder prior to purchase.
Progressive Retinal Atrophy
Progressive Retinal Atrophy (PRA ) refers to a group of inherited diseases that cause loss of sight in many dog breeds. Most forms of PRA are believed to be inherited as simple Mendelian recessives. They differ in their age of onset and histology. Progressive Rod/Cone Degeneration (prcd) is the form of PRA found in the Australian Cattle Dog (ACD) and in the Australian Stumpy Tail Cattle Dog (ASTCD).
Prcd is known to have caused blindness in Cattle Dogs as young as 3 years old. Age of onset is, however, variable. Some Cattle Dogs do not develop clinical signs of the disease until they are 6 or 7 years old, or even older.
Prcd has been known in ACDs population from early in the breed's history. Old stories have been handed down about "moon-blindness" or "night-blindness" and inability to see in subdued light. These observations are often a sign of prcd. More recently, it become evident that the incidence of prcd was alarmingly high. Because prcd is commonly late in onset, affected animals may parent litters before the disease is diagnosed.
Wooleston Blue Jack, and his ancestors Little Logic and Logic Return are behind all modern ACDs. Pedigree study suggests that the popularity of this lineage, and the genetic convergence on it, may have contributed to increased incidence of prcd. It is probable that Little Logic carried the disease. For example: Glennie Blue Gem, whelped in 1964, was closely line bred to Little Logic. Her blindness is thought to have been the result of prcd.
Prcd is inherited as an autosomal recessive. This means that an affected dog must have inherited the prcd gene from both parents. A dog that inherits the prcd gene from one parent and the healthy gene from the other will not develop the disease, but can pass the prcd gene on to its offspring. Such a dog is known as a carrier for prcd. A dog which has no copies of the prcd gene can’t (obviously) pass on the disease – such a dog is known as clear for prcd.
Prcd in ACDs attracted the interest of Dr Greg Acland, an Australian veterinary ophthalmologist holding research and academic positions in the USA. In 1996, Dr Acland collected blood samples from over 100 ACDs in the United Kingdom and Netherlands for initial study. Blood samples from ACDs in North America and Australia later enlarged the collection. Dr Acland’s research, carried out at Cornell University, was successful, in 2002, in proving a DNA test that can (a) identify prcd affected ACDs before the disease becomes clinically evident, (b) can determine whether a dog carries the disease (even though it is itself unaffected), and (c) can identify dogs that are completely clear of the disease. More information can be found on the following web sites:
Studies of congenital deafness in the
dog are limited although those breeds to date with the
highest prevalence include the Australian Cattle Dog,
Australian Shepherd, Bull Terrier, Catahoula, Dalmatian,
English Cocker Spaniel, English Setter and West Highland
Inherited congenital sensorineural deafness
is usually, but not always associated with pigmentation
genes responsible for white in the coat, but, as the Dalmatian
is influential in the overall makeup of the Australian
Cattle Dog, the breed is unfortunately plagued with this
Through extensive research it has been
established that deafness does not develop in dogs until
the first few weeks of life, with normal development occurring
to that point. Studies have shown that Australian Cattle
Dogs do not go deaf until weeks 3-4 after birth. The histologic
pattern that occurs in most dogs breeds is known as cochleo-saccular,
or Scheibe, type of end organ degeneration.
Since the ear canal does not open until
approximately 14 days in dogs, and deaf puppies cue off
the responses of litter mates, and it is not uncommon
for deafness to go unrecognized for many weeks. In some
breeds, deaf puppies will display more aggressive play
with litter mates because they do not hear cries of pain,
but deaf puppies after weaning will not waken at feeding
times unless physically shaken.
Assessment of the presence of auditory
function requires a simple test known as brainstem auditory
evoked response or BAER as it is commonly known. In this
test a computer based system detects electrical activity
in the cochlea and auditory pathways in the brain in much
the same way that an antenna detects radio or TV signals.
Management of deafness comes back to
the old saying "You must be cruel to be kind".
A bilateral or full deaf pup must be put to sleep as the
quality of life of deaf dogs is greatly diminished. Unilateral
deafness where the dog has full hearing in one ear only
is a easier problem to manage and these dogs make ideal
pets with the owners often unable to detect any impairment.
Some dogs with unilateral deafness will show a directional
deficit and may not immediately reactive to your presence
if sleeping soundly with the good ear on the ground. However,
there is no evidence to discourage breeding from unilaterally
deaf dogs, although preference to breeding with full hearing
dogs will with the cooperation of all breeders eventually
prevent further affected dogs and the ultimate increase
in the prevalence of the disorder.
Link to http://www.sheepdog.com/diseases/pra/pramenu.html
for more information
Hip Dysplasia appears in many breeds
of dogs. In some breeds it is the most common cause of
osteoarthritis or degenerative joint disease. The term
dysplasia is a developmental condition that results in
abnormal looseness or laxity of the hip joints.
The signs of HD vary from decreased exercise
tolerance to severe crippling although some dogs may never
shows signs of dysplasia and generally remain very fit
and active. Even though a large percentage of Australian
Cattle Dogs today do not work stock as such, they channel
their energy and intelligence into other activities including
obedience, agility, tracking, showing and being the active
family member therefore the exercise diminishes the affects
of this common and often crippling disease.
Any diagnosis of Hip Dysplasia must be
made via expert radiographic diagnosis. This involves
taking x-rays of the joint and typically sending the film
to organizations that will evaluate, register and certify
the dog. You cannot make a reliable diagnosis of HD on
the basis of external symptoms such as lameness or gait.
There are many types and degrees of patella luxation.
The patella or kneecap can luxate or dislocate medially
which is towards the body midline or laterally which is
away from the midline and can be traumatic or congenital
in origin. The problem has been evident in Australian
Cattle Dogs for some time with the breed suffering from
lateral luxation in most cases diagnosed. Surgical correction
is not usually necessary unless the dogs shows symptoms
such as pain or gait abnormalities. The condition can
be easily diagnosed by your veterinarian and a simple
check of the patella can be performed by your veterinarian
to see if the dog is predisposed to the condition. In
Australian Cattle Dogs luxating patellas has shown to
be an inheritable problem, and as such a dog that possesses
this problem should not be bred as the possibility of
it's progeny inheriting the condition is high. Also studies
show that in about 50% of cases treated surgically the
dog demonstrates reoccurring patellar luxation in as short
a time as 1 year.