Pedigree Dogs
Exposed
Tuesday 19 August
9:00pm -
10:00pm
BBC1 East
An in-depth
investigation
into the health
of pedigree
dogs. The
programme
examines the
level of
inherited
disease and
other welfare
concerns in
man's best
friend,
featuring
interviews with
experts. It
reveals the
surprising
historical
factors that
have contributed
to problems in
some breeds and
explores what
might be done to
tackle these
serious and
debilitating
health issues.
Director Jemima Harrison; Producer Jon
Lane,
Passionate Productions. Previous films
include the widely acclaimed "Can Dogs Smell
Cancer".
Director Jemima Harrison has owned dogs
all her life. She currently owns Flatcoat
Retrievers and co-ordinates
Black Retriever X Rescue
Extent of inbreeding in pedigree dogs
revealed in new study
By Laura Gallagher
Friday 15 August 2008
The extent
of inbreeding in purebred dogs and how this
reduces their genetic variation is revealed
in a new study by Imperial College London
researchers. Inbreeding puts dogs at risk of
birth defects and genetically inherited
health problems.
These issues and the researchers'
findings are highlighted in an upcoming TV
programme entitled "Pedigree dogs exposed,"
which will air on BBC One on Tuesday 19
August 2008 at 21.00 BST.
Particular dog breeds are believed to be
prone to particular health problems and
birth defects. For example, Dalmation dogs
are predisposed to deafness, many Boxer dogs
have problems with heart disease, and
disproportionate numbers of German Shepherd
dogs have an abnormal developmentof the hip
joints known as hip dysplasia.
Inbreeding in pedigree dogs arises
because certain dogs, prized for exhibiting
the characteristics desirable for that
breed, are used to father many litters of
puppies. When dogs from these litters come
to be mated, some will be paired with dogs
having the same father from other litters.
Over generations, more and more dogs across
a particular pedigree are related to one
another and the chances of relatives mating
increase.
Recessive genetic variants only have
adverse health effects such as deafness when
an individual carries two defective copies
of the gene. If a popular sire carries just
one defective copy, he will not show the
problem himself and nor will his puppies.
However, the defect may become common in
later generations if his grandpuppies and
great grandpuppies are mated with each
other, rather than introducing new genetic
traits by breeding outside their relatives.
Although the problems associated with
inbreeding have been known for many years,
prior to the new study it had not been
systematically measured. For this study,
researchers from Imperial used mathematical
modelling to analyse how dogs were related
to one another within ten different dog
breeds including the Boxer and Rough Collie.
They looked at the parentage of eight
generations of dogs, using records collected
from 1970 to the present day by the UK
Kennel Club.
The researchers' analysis showed that,
for example, Boxer dogs were so closely
related to one another and had such little
genetic variation between them that
genetically, 20,000 dogs looked like a
population of about 70. In the Rough Collie
breed, 12,000 dogs looked in genetic terms
like a population of about 50.
Such small effective population sizes
mean that the chances of a dog breeding with
a close relative, resulting in birth defects
and genetically inherited health problems,
are high. The researchers argue that those
involved in breeding dogs should encourage
breeding from a larger pool of potential
mates in order to create greater genetic
variation and lessen dogs' chances of
inheriting genetic disorders. They suggest
measures such as limiting how many times a
popular dog can father litters; encouraging
mating across national and continental
boundaries; and relaxing breed rules to
permit breeding outside the pedigree.
Professor David Balding, the
corresponding author of the research from
the Division of Epidemiology, Public Health
and Primary Care at Imperial College London,
said: "The idea that inbreeding causes
health problems in particular dog breeds is
not a new one, but we believe ours is the
first scientific study to explore this issue
and analyse the extent of inbreeding in a
systematic way, across many breeds. We hope
that following our work, dog breeders will
make it a high priority to increase the
genetic diversity within different breeds.
Otherwise, we will see growing numbers of
dogs born with serious genetically inherited
health problems."
The researchers carried out their
analysis as part of an effort to explore how
understanding disease in dogs can help
inform research into human disease. The
research was funded by the Biotechnology and
Biological Sciences Research Council.
Further information about the research is
provided in the study, which is published in
the journal Genetics:
"Population structure and inbreeding from
pedigree analysis of purebred dogs,"
Genetics, 179(1): 593–601, 2008.
doi:10.1534/genetics.107.084954 Calboli FC ,
Sampson J, Fretwell N, Balding DJ
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main difference is the number of compressions vs. breaths. The American
Red Cross recently changed the requirement for humans to one breath per
30 compressions. Pet CPR is one breath to five or six compressions. The
same technique is used, except with small animals you use one hand.
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the animal is not breathing and has no pulse, close its mouth and place
your mouth over the animal's snout and blow forcefully. Then alternate
breaths with chest compressions.
