AT July-Aug 2005

there were a few basic things we needed
to know: inheritance, neonatal health, litter
size, tail status ofparents, and tail status of
offspring. Inheritance can be deduced from
either studying a large sample or several
generations, and by looking for clues in
other breeds. Submitting samples for a
DNA test to determine if the gene for the
NBT inAussies is that same as in Pembroke
Welsh Corgis is one way of arriving at
an answer more quickly. I am currently
investigating the possibility of doing this
and will post information at a later date if
it is indeed doable.
Meanwhile, I will be collecting
Australian Shepherd litter information
through this year (2005) and then
publishing the results. The information I
need from breeders takes a relatively short
amount of time to fillout and provide to me.
Most ofthe data have been sent to me via e-
mail, as the data forms are available online
or can be e-mailed as attachments upon
request (my e-mail is imgnr@dnaco.net").
Pictures are helpful to verify tail lengths,
plus I may ask to use some for the final
article; however, they are not mandatory.
I request a five-generation pedigree, some
general information on the parents (such as
previous litter sizes and tail status before
docking, if known), and then the litter data
(which includes tail length or category, total
number ofpups, number of stillborn pups.
In Other Words
and notes on any neonatalhealth problems,
particularly in regards to the spinal area or
hind quarters). That's it.
As of this writing, I have just over
50 litters in the study. The more data, the
more accurate the findings will be, so any
and all breeders are invited to contribute,
including litters with all full tails as well
as those with NBT pups in them. Full tail
litters will help serve as a control group
for comparison. The objectives of this
study are to determine a possible mode
of inheritance for the natural bobtail trait,
to find out whether or not there is any
clear correlation between the presence
of the gene and neonatal health defects,
or if the presence of the gene leads to a
reduction in litter size or has no effect on
it. Early results indicate that the gene for
the NBT in Aussies may be inherited in the
same manner as it is in Pembroke Welsh
Corgis—a dominant gene with modifying
factors that determine actual tail length
in the NBTs—as it appears that a NBT
parent will usually produce some NBT
pups, no matter who that dog is bred to.
Whether or not it is the same gene as the
Pembrokes could only be proven by DNA
testing. It is unclear whether there is an
increase in spinal defects or other serious
health problems, as there simply has not
been enough of these problems reported
in this study thus far. It could be because
that although spina bifida and imperforate
anus do exist, they are actually rare in our
breed. In the matter of litter size when the
NBT trait is present—a final analysis of
data will give us some indication about
this, but thus far litter sizes have varied
in both litters with all full tails and litters
with NBTs present. What will be most
interesting to see is what crosses ofNBT x
NBT will produce in the way oflitter size,
but at this point there have not been enough
of such crosses to state anything one way
or another.
The two data sheets needed for
participation in this study may be
downloaded from http://www.dnaco.net/
~imgnr/nbt study.htm or received
as attachments directly from me at
imgnr@dnaco.net. Although pedigrees will
be requested on all litters to help determine
the mode of inheritance, no information
will be disclosed to the public (or to any
individuals). Everything is confidential.
Study results will only contain numerical
data. No pedigree information or specific
sires or dams will be mentioned.
My thanks to Heike Poole, again, for helping
me make sure I understood the German laws
before putting them into my own words, and to
CASharpfor helping me create the data sheets
andher input. Atid ofcoursemany, many thanks
to all those breeders out there who have sent
along data and shared information!
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108 AUSSIE TIMES I July-August 2005