COEFFICIENT OF INBREEDING (COI) CALCULATION
Written by Celeste Pongrácz
Revised March, 2008
COI is the calculation of the level of inbreeding in a dog or
litter.
High COI percentages increase the probability that genetic
defects will be carried from common ancestors on both sides
of the pedigree and will match up to cause the actual genetic
disease or defect in the animal.
Many other problems of a high COI also affect dogs, such as
Autoimmune disease and inbreeding depression symptoms,
which result in reproductive and longevity issues.
A COI of 12.5% is equivalent to a half brother - half sister
mating or a grandparent - grandchild mating.
A COI of 25% is equivalent to a parent-child or brother -
sister mating.
Ideally, the COI of a litter should not exceed 6.25% or the
average COI of the two parents. It is highly recommended
to avoid COI percentages in excess of 12.5% and a COI in
excess of 20% should be totally avoided.
Some genetically inherited diseases and faults in herding
breeds are:
Hip and elbow dysplasia
Patella luxation
Epilepsy
Eye disease such as: cataracts, Collie Eye Anomaly (CEA)
and Progressive Retinal Atrophy (PRA)
Cancer
Allergies and skin problemsRetained testicles
Autoimmune diseases
Bad bites and missing teeth
Unacceptable colors
Temperament problems such as shyness and aggressiveness
Inbreeding depression symptoms are seen as the loss of
viability or function resulting from excess inbreeding.
Sometimes these symptoms are very subtle and gradual and
are often blamed on diet, pollution and other environmental
factors. While these factors may also contribute, it is the
dogs genes that make it more susceptible. The most
frequently seen inbreeding depression signs are:
Chronic poor health/poor keepers
Higher incidence of disease in a line (or breed) of one or
more diseases than is seen in the breed or canines as a
whole
Higher incidence of immune system diseases
Unusually small litter size
Difficulty in getting and keeping bitches pregnant
Bitches that abandon a litter or are poor mothers
Bitches that kill or damage puppies intentionally or by lack
of care
Studs that are indifferent to a bitch in standing heat
Studs that cannot breed without help
Low sperm count
Earlier average age of death in a line or in the general breed
population
All of these factors make it incredibly important that you do
the COI calculation on any planned litter. Keeping the
breed healthy is easier than cleaning it up after the fact.
Once the gene pool is closed and the genetic base remains the
same, the genetic situation can either remain stable or
deteriorate, it cannot improve without new genetic material
brought in via outcrossing to another breed or the use of
non-registered stock.
Inbreeding, linebreeding and the usage of popular sires are
methods of the past ages of dog breeding, their time is over.
Nature goes to great lengths to avoid inbreeding, so should
today’s breeder. COI calculation can give the breeder an
indication of how inbred a dog or litter will be. Knowing
this percentage will enable you to make the best choices
towards reducing inbreeding in your dogs.
Today the emphasis should be put on health, temperament
and working ability if purebred dogs are going to survive
into the next hundred years. Active concern for health
should be your number one breeding goal, because without
health, you have no dog.
Unfortunately you cannot simply download a free program
for calculating a COI off of the internet and add into it the
dogs on the pedigrees you hold in your hands. You cannot
even pay for a program and add in this information and
expect to get the right percentages. You need to have all the
dogs behind the pair you plan to mate for 10 generations
back in order to get the correct percentage as this is how far
back the generations need to be taken into account.
You may not realize this, but 1 dog with 10 generations
behind it has 2046 dogs in its 10 generation pedigree! If you
want to calculate the COI of a pairing, you need to add in
2046 dogs from the one parent and 2046 dogs from the
other, that’s 4092 dogs.
10 generations may seem like a lot of generations and a lot
of dogs, but it is not and it is figured on a sliding scale with the
generations affect reducing by the proper proportions
as they recede. I have a professional database program
that I purchased in 2004 and have put hundreds of hours of
work into it. I presently have over 5500 Mudi’s that I have
entered into my database. I continue to work on it and add
in more dogs as I find them, some new ones and some older
ones. As this is a continual process, COI’s will change from
time to time, they do not get lower however, only higher,
but the changes are usually small.
I provide free COI calculations for the Mudi breed to
anyone, no fee is ever charged. Please email me with the
names of the dogs that you would like to breed together at:
peter.celeste.pongracz@gmail.com
"Inbreeding was once a valuable tool in shaping today's
breeds. As these have now reached a high degree of
homogeneity, it has lost its importance and turned into a
fatal and disastrous habit." Hellmuth Wachtel, Ph.D.
"The breeding of purebred dogs is akin to (breeding
laboratory mice)...(most breeds) are becoming
progressively more inbred. My observation is that most are
on the road to extinction, but most breeders do not even
realize they are part of an experiment." John B.
Armstrong, Ph.D.
"However, we ignore the biological impacts of the practice
(inbreeding) at our peril - or more accurately, the peril for
our dogs." C.A. Sharp
I would like to extend my sincerest thanks to C.A. Sharp for
all of her efforts to help us breed healthier dogs and to all of
the researchers that work towards providing us the
knowledge and tools to accomplish this.
ANOTHER EXCELLENT COI ARTICLE:
http://www.ashgi.org/articles/breeding_coi.htm
