AT July-Aug 2005

fairly common and may be so subtle only
the most observant person would notice
them. Others involve ritualized behavior
like "ly-biting"or tail-chasing. A dog that
seems to zone out may be having a mild
seizure..
Seizures originate in the brain at a
specific focus. Over time, the focus can get
larger as it begins to affect adjacent cells.
When this happens the seizures get worse
and what was an occasional space-cadet
episode turns into full-blown seizures.
One pupin my currentlitterhas very small
testicles and another is cryptorchid. I've
placed the cryptorchid in a pet home, but
should I do the same with the other?
The small testicles in the one pup, combined
with the cryptorchidism in his litter brother,
is a reason for concern but not necessarily
one that should wash him out immediately.
Have you discussed this with your vet?
Were there any environmental issues, like
meds given the bitch during gestation, that
may have resulted in small testes?
Ifthe vet doesn't think there's any need
to be concerned, I'd give the pup time to
grow up and start pumping male hormones.
If his testes remain abnormally small you
may want to make sure his semen is normal.
If it is, then I wouldn't worry about it other
than to avoid bitches with a family history
of testicular abnormalities.
Atfour years old, my girl had erlichia
and now, at eight, she has lung cancer.
Didthe erlichia infection sether up to get
cancer later?
While it is true that some infections can set
the stage for later cancers, I'm not aware of
any research linking erlichia and any type
of cancer.
Typically, lung cancer is caused by
inhaled carcinogens such as second-hand
cigarette smoke. There was a study a few
years back that showed dogs owned by
smokers were at higher risk for this type
of cancer. Since dogs do a lot of snuffling
along on the ground, it is also possible for
them to inhale something that might set
them up for lung cancer down the line.
How much consideration isgiven to stress
being a triggerfor some of the immune
systemproblems, sincestresscan lowerthe
immune system's response to disease?
Therolestress plays inanydisease probably
varies from individual to individual and
from one time to another. Some of us.
Q&A
both dog and human, handle stress better
than others. At some point in our lives, all
of us experience stress.
There is no doubt that stress affects
immune system function and not just by
making you more susceptible to whatever
bugs might be around. I can remember
the ophthalmologist who treated my
autoimmune eye disease telling me to avoid
stress. I was going through a divorce at the
time and told him if he could come up with
a way to have a stress-free divorce, we'd
write a book and get rich!
While there is no way to put exact
figures on it, stress can affect the immune
system in several ways:
• Lower ability to resist infection
• Trigger immune-mediated diseases
• Decrease the system's ability to destroy
potentially cancerous cells
Stress is not a good thing if you have
too much of it or don't handle it well.
Negative stress events are fairly obvious,
but even positive things (marriage, new
baby, moving to a new home, new job,
holiday gatherings) can induce stress for
people. Positive stressful events from your
dog's point of view, would include things
that cause major excitement or significant
changes in routine.
How can you say epilepsy is not caused
by a dominant gene with incomplete or
variablepenetrance when it's notdifficult
tofindcurrent-daygeneticists referring to
these as a suspected mode ofinheritance
for one thing or another?
True, they do. However most, when
pressed, will admit that they aren't sure why
Significant Aussie
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a trait does that. Incomplete and variable
penetrance are "science-speak" for "I don't
know what the heck is happening here." But
you can't put the latter in a peer-reviewed
journal.
I tried a few years back to find one
single solitary trait that was proven to be
single-gene dominant with incomplete or
variable penetrance. I corresponded with
researchers I know and put the question to
discussion lists on which researchers with
an interest in canine genetics participate.
Nobody could come up with any.
Zip. Zilch. Nada.
Traits of this type may have a single
major gene, but even so the variation in the
trait suggests additional causes. They are
almost certainly either polygenic or have
a significant environmental aspect. I don't
think anyone questions that environment
plays a role in many genetic diseases. Hip
dysplasia is a classic example, autoimmune
diseases are environmentally mediated and
some epileptic dogs seize only in certain
situations.
Too often, breeders fall into a selfdefeating
trap by grasping at the straw of
variable/incomplete penetrance to mean
that a problem, whatever it is, most likely
came from the other parent, not their own
animal. Please don't do this. In the long run
it will hurt you, dogs, and the breed.
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AUSSIE TIMES I July-August 2005 77