2018 May June

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Featured Research
Border Collie Collapse (BCC)
Q&A
NOTE: This was formerly called Exercise Induced Collapse (EIC). The
new name has been given to distinguish between the similar disease
in Labradors, for which a gene has been identified, and the condition
seen In herding dogs, including Aussies. It is extremely frequent in
Border Collies, which is what led to the name.
To identify genes responsible for causing BCC in Australian Shepherds,
Border Collies and other breeds in order to develop a DNA screening
test.
Dr. James Mickelson
University of Minnesota
purebred Australian Shepherds that have exhibited an episode of
collapse during exercise.
blood preferred
Katie Minor
University of Minnesota
C339 Veterinary Teaching Hospitals
1352 Boyd Ave.
St. Paul MN 55108
612-624-5322
minork@umn.edu
For information on other studies looking for samples from Aussies, go to:
www.ashgi.org/home-page/how-you-can-help/research-support/current-research-for-aussies
If you breed her to a non-merle you
will probably get a litter that appears to
be all non-merle or maybe mostly nonmerle
with a few identifiable cryptics that
have one or a few small merle spots. The
question you need to answer for yourself is
how much risk are you comfortable with? If
you can’t bear the possibility that you might
produce a double merle, then don’t breed
the new boy to your red merle girl. If you
are willing to chance a rather low risk, then
go ahead. For more on cryptic merle see:
http://www.ashgi.org/home-page/geneticsinfo/coat-color/cryptic-merles
So how do I use COI information? What
COI should a dog have? Do you need to
seek mates that are “lower” on the issue
scale AND will produce a lower COI litter?
Can I use it to dilute the risk for bad stuff?
Use coefficients of inbreeding (COI)
as a yardstick to track inbreeding levels in
your breeding program. While you might
have an excellent reason to do a high-COI
cross, you want the overall trend to be
steady or even down, not up.
If we were in a perfect world – which
this decidedly is not – COI should be
no more than 6.5%. In the real world,
we need to keep in mind that the breed
average is around 12.5% – the same as a
half-brother/sister cross. Try not to exceed
breed average. Go lower if you can. If you
get below 10% you are doing well for this
breed at this point in time.
COI is a measure of probability that
any given gene will be homozygous by
descent. In other words, if WTCH OTCH
ATCH IntCh Bigbucks Studly TDX UDX
is a double grandsire and he is the only
common ancestors in the whole pedigree
except for his own pedigree for ten
generations, your dog would have a COI
of 12.5% and you’d have a one-in-eight
probability of getting a double dose of any
one of his genes. Since he has around 19K,
genes, you will double up on quite a few.
For the good things, that’s wonderful, But
ol’ Studly will have a few bad ones lurking
around his genome just as every dog does
so you stand a chance of getting a pair of
one or more of them, too. COI can’t predict
which genes will double-up, just that some
will. The higher the COI, the larger the
number that are homozygous so the greater
the risk that some of those pairs might not
be so good.
Of course, most pedigrees aren’t that
simple. You can have multiple common
ancestors often appearing more than once
on each side and in different generations.
This is why it takes a computer to calculate
COI. Use ten generations because adding
generations beyond that rarely makes a
significant difference in the result and doing
fewer makes the number artificially low.
By lowering COI you might lower
risk for doubling up on things, but if you
are looking at a specific trait you want to
eliminate, like HD, you need to research
pedigrees for that rather than depend
on a low COI to avoid it. If you breed a
dysplastic Aussie to a dysplastic Labrador
the litter will have a zero COI but will likely
include dysplastic offspring.
Breeding is a complex business. There
is no one magic bullet that will guarantee
everything will come out the way you want
it to. For COI – all other things being equal
– try not to produce a litter with a higher
COI than the average of the two parents’
COIs. Example: If sire is 12.5% and dam
is 23.0%, you would want the litter to be
no more than 17.8%.
A really good young stud dog that does a
lot of winning could conceivably produce
hundreds of puppies. Can’t this be a
problem if it turns out down the line that
he carries genes for something we can’t
test or screen for? What’s the best way to
manage a dog like this?
This risk is something a stud owner
needs to take into account if she has a
superior young male and lots of bitch
owners clamoring to breed their girls to
him. Every dog carries some genes for
something you don’t’ want, whether for
structure, behavior or health. Overuse of
studs – usually excellent individuals with
stellar show or performance careers – has
led to significant increase in a genetic
disease in many breeds, including this
one. This isn’t restricted to dogs; if you
know Quarter Horses, think of the stallion
Impressive. The quickest way to make a
rare disease common is a popular sire.
It is best to start any young male’s
stud career by breeding him to bitches
who have had a couple litters so you have
an idea what they are apt to produce. This
way you can judge his contribution more
clearly. If they are your own, even better
because you will have a better chance of
following those pups as they mature. Once
you know his qualities aren’t skin deep you
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