Border Collie stands alone in its exceptional ability to work livestock.
ABCA defines the breed by this working ability. The main goal
of any Border Collie breeder should be to produce sound, useful,
working dogs. While Border Collies also excel in many non-herding
activities, they should be bred primarily to work livestock. The
ultimate responsibility for maintaining the integrity of this as
yet unspoiled breed lies with the breeders. Breeders are urged to
take this responsibility seriously. Puppy buyers are encouraged
to buy only from those breeders who do take this responsibility
Both breeders and buyers should understand there are risks
involved in any breeding, regardless of the amount of care taken
to avoid problems. In order to ensure a healthy gene pool for future
generations of Border Collies, breeding prospects should be evaluated
with reasonable concern for potential problems and realistic goals
for what will be produced. The breeding prospect should be considered
as a whole being, with positive and negative aspects of the individual
being weighed and balanced for an overall picture of a dog's suitability.
Breeding should be undertaken with thoughts of what the parents
have to offer to their pups that could benefit the breed.
To be considered a genetic disease, a health problem needs
to have been demonstrated to be heritable, that is, passed on through
one or both parents. Some diseases have high heritability, which
means if the genes are present, the individual will have the disease,
and some diseases have low heritability, meaning both genetic and
environmental factors are involved in whether the disease occurs.
It is generally easier to control diseases with high heritability
because all individuals with the genetic makeup for the disease
can usually be identified. The term heritable disease should be
distinguished from the term congenital disease, or problems that
are present from birth, which may or may not be heritable.
Border Collies are considered to be a generally healthy breed.
However, as in all animals, there are some potential health problems.
This information is presented to help both breeders and buyers to
become more aware of some of the health and genetic issues in the
breed at this time.
The primary genetic diseases currently thought
to be a problem in the breed are as follows:
HD is by far the most prevalent known genetic disease that affects
Border Collies. Factors that contribute to the development of HD
ultimately cause the hip joint to be damaged. Joint damage called
osteoarthritis, also known as degenerative joint disease (DJD) is
manifested by cartilage and bone breakdown and irregular bony remodeling
in response to stresses and inflammatory processes in the joint.
DJD is, in effect, the identifiable result of factors that cause
HD. The standard for diagnosing HD at this time is still the front
extended-leg view of the hips on x-ray such as that evaluated by
The Orthopedic Foundation for Animals (OFA). OFA reports a 12.6%
affected rate for Border Collies evaluated from 1974-2000. This
HD incidence ranks them somewhere in the middle of the dog breeds.
Pre-submission screening and selection for probable favorable OFA
results by owners and their veterinarians very likely skews this
percentage significantly to the low side. Therefore, the true incidence
of HD is probably much higher, possibly as high as double the OFA
figure. If true, this would mean, on average, one out of every four
Border Collies has HD.
Despite what some may claim, data from numerous scientific
studies provide overwhelming evidence that HD is an inherited disease.
It is thought to be caused by at least three and possibly as many
as six primary genes. The number of genes involved, combined with
the high incidence, means it's probable that most Border Collies
are at least carriers of one or more of the genes that can contribute
to the development of HD, even if they don't have the disease themselves.
To confuse matters more, the expression of the disease is affected
by environmental conditions such as the type and amount of food
a dog gets at critical growth stages, as well as the type and amount
of exercise and activity it gets. It must be remembered, however,
that these environmental factors do not cause HD. They merely affect
whether the HD genes present in that individual will be expressed
to the fullest. Even if the expression of HD in a certain individual
is suppressed by careful control of environmental factors, you have
not changed the dog's genetic makeup. That dog will still pass on
the genetic tendency for HD just as if it actually had the disease.
Conversely, if a dog does not have the genes for HD, it won't develop
the disease no matter how it's raised.
The possible incidence of one in four dogs may seem falsely
high if the presence of HD is defined by dogs showing significant
lameness. The clinical symptoms of HD do not always correlate
well with the severity of the disease as judged by radiological
findings. Border Collies with HD that are fortunate enough to show
few if any symptoms may have progeny that are not so fortunate.
The exact complex combination of genetic and environmental factors
that contributed to an individual's lack of symptoms will not occur
in its pups. Therefore, it is important to remember that a
high tolerance of an individual for the effects of HD does not mean
that individual is suitable as a breeding prospect.
The best way, at this time, to avoid producing puppies with
a predisposition to develop HD is to test both parents and be aware
of the hip status of other related dogs such as the parents' other
progeny, the parents' parents, and the littermates and half siblings
of the parents. The more tested, unaffected dogs there are in the
pedigrees, the better the chances of producing unaffected pups.
Unfortunately, even following the most stringent guidelines, puppies
may still be produced that will develop HD. This does not mean there's
no point in testing parents before breeding them. This
line of false reasoning is akin to arguing that, because working
parents will occasionally produce pups that won't work, there's
no point in testing the working ability of breeding stock. Selection for good hips will increase your chances of producing
pups with good hips, but it's unrealistic to expect that puppies
with HD will never be produced from tested, unaffected parents.
Likewise, it is unrealistic to expect every dog who has ever produced
a pup with HD to be banned from breeding. Since it's likely that
most non HD-affected Border Collies are carriers of one or more
of the genes for HD, most dogs will produce at least one pup with
HD if bred enough times. Sooner or later, a cross with another carrier
will produce the wrong combination of the HD genes and an affected
pup will result.
Given the incidence and complexities involved with HD in
our breed, the recommendations at this time are to breed only
hip tested, unaffected parents. Also, try to plan crosses
having as many tested, unaffected dogs in the pedigrees of both
parents as possible. If an affected puppy is produced from a cross
of two unaffected parents, at the very least, don't repeat that
particular cross because that affected puppy has proven
that the two parents can together provide the right combinations
of genes to create more puppies with HD.
The ABCA Health and Genetics Committee is investigating a
promising new technique that measures several factors involved in
the development of HD. This procedure involves taking hip x-rays
on a sedated dog while the dog is in a kneeling position. This angle
is favorable for identifying strengths and weaknesses in the hip
joint in a more natural, weight-bearing position. This type of measurement
is called a Dorsolateral Subluxation (DLS) measurement. ABCA is
planning a study to evaluate this technique in 8-12 month old Border
Diagram of the position for
x-ray in the DLS procedure
Eye Anomaly (CEA) CEA is a congenital disorder where the parts of the
eye, particularly the retinal area, do not develop normally. The
severity of the disease ranges from no visual impairment to blindness.
It is not a progressive disease and affected dogs usually have only mildly impaired vision.
This disease is much more straightforward than hip dysplasia in both
its inheritance patterns and in our ability to control it. CEA is
an autosomal recessive disorder. Autosomal means it is passed on
and expressed equally in males or females. Recessive means a dog
may carry a "bad" (mutated) CEA gene and pass it on to its offspring without
having the disease itself. A dog is defined as Clear (or Normal) if it has no
"bad" CEA genes. A dog is defined as a Carrier if it has one "bad" CEA
gene and one normal gene. The eyes of both the Carrier and the Clear dogs will be unaffected by the disease. A
dog which has two "bad" CEA genes is defined as Affected. The
outcomes of the different crosses of these dogs are as follows:
Clear X Clear = 100% CEA Clear puppies
Clear X Carrier = on average, 50% Clear, 50% Carriers
Clear X Affected = 100% Carriers
Carrier X Carrier = on average, 25% Clear, 50% Carriers,
Carrier X Affected = on average, 50% Affected, 50% Carriers
Affected X Affected = 100% Affected
The incidence of CEA in Border Collies in North America is
about 2.5%. The carrier rate is probably ten times that figure,
It is possible to determine whether a dog is Affected with CEA by having it examined by a Diplomate of the American College of Veterinary Ophthalmologists (DACVO). To be sure of obtaining accurate results, however, puppies should be examined before they are 12 weeks of age, because some dogs have a mild form of the disease called "go normal," where normal tissue grows over and covers up the diseased area of the eye as the dog matures. These "go normal" dogs cannot reliably be identified by an eye exam in adulthood, but they will pass on a "bad" CEA gene to their offspring just as if they had full blown expression of the disease.
Until a few years ago, the only way to know if a dog was a Carrier was for it to produce an Affected puppy. Since there are so many unknown Carriers, that meant there was no way to prevent inadvertently producing Affected pups. Since 2005, however, there has been a reliable DNA test for the CEA gene, which can determine whether a dog is Affected, a Carrier, or Clear. The test is being administered through OptiGen, LLC, and further details about it can be obtained on their web site at www.optigen.com.
It is recommended that breeders utilize the OptiGen test to determine the status of all dogs used for breeding. A Clear (Normal) dog bred to a Clear (Normal) dog will produce only Clear puppies, so the offspring of such a mating need not be DNA tested; their status is known. An Affected dog should be bred only to a Clear dog, and only when the dog's exceptional merits are such as to justify a breeding that will produce pups which will all be Carriers. Carriers, too, should be bred only to Clear dogs, in order to avoid producing affected pups; at the same time, breeders should not exclude Carriers from their breeding program, as this would be detrimental to the goal of maintaining the highest level of working ability in our breed and would also tend to constrict the gene pool. All pups with a Carrier parent should be tested to determine their CEA status before being bred. If testing all breeding stock is not feasible, at a minimum breeders should ensure that one parent of any litter is DNA Clear, as this is the only way to be sure that Affected pups will not be produced. Breeders and owners should be frank and forthcoming in informing anyone inquiring about a breeding or a puppy purchase about the CEA status of the dogs involved, and the significance of that for any offspring they may have.
Epilepsy is a disease characterized by seizures or "fits"
as they are sometimes called. Although it's clear Border Collies
can be affected with epilepsy, the incidence and heritability in
our breed are unknown.
The ABCA is supporting research aimed at finding the gene(s) that may cause epilepsy in the breed.
Since there can be many causes, determining why a dog has
seizures is a complex process. The diagnosis of primary epilepsy
is made based on negative results for other causes of seizures.
Therefore, it is a diagnosis made by exclusion rather than by a
specific test. Since we have little breed-specific information to
go on, ABCA breeding recommendations concerning this disease are
based on those for other affected breeds in which the disease is
more well-defined. Recommendations are: Do
not breed affected dogs. If two unaffected dogs produce an affected
puppy, do not repeat that cross.
Genetic diseases not considered to be a
significant problem in the breed at this time:
Retinal Atrophy (PRA) PRA is a progressive disease where tissue
in the retina of the eye is destroyed. It may initially be noticed
as decreased ability of the dog to see at night, and may eventually
progress to total blindness.
Despite the persisting impression that this genetic disease
is prevalent in the breed, extensive investigation has shown the
incidence of PRA in Border Collies in North America to be extremely
low to non existent. Therefore, the ABCA does not currently consider
it a major health concern.
dysplasia Elbow dysplasia is a general term used for
what is essentially three different types of degenerative elbow
disease. These diseases may occur singly or together and are thought
to be caused by several different genes.
More and more owners are having their Border Collies' elbows
evaluated each year. However, OFA reports a 0% incidence of elbow
dysplasia for 210 Border Collies tested from January 1974-December
1999. ABCA does not consider elbow dysplasia a significant health
problem in the breed at this time.
Common diseases with questionable heritable
Dissecans (OCD) OCD is a condition that occurs primarily in puppies
between the ages of 4-9 months, but can also be found in older puppies.
It is considered to be a common disease in rapidly growing dogs
of large breeds. However, medium breeds such as the Border Collie
can also have a high incidence of this disease. It is seen twice
as often in males as in females. The shoulder joint is the most
commonly affected site but it can be seen in stifles, elbows, hocks
or other joints. The diagnosis is usually confirmed by x-ray of
the involved joints. In approximately one third of the cases
of OCD, the disease is bilateral (in both joints). Occasionally,
it is present in several different joints in the same individual.
OCD is thought to be caused by a problem in the growth rate of the
joint cartilage relative to the underlying subchondral bone.
Although the factors that cause OCD are not completely understood,
direct factors considered to be involved in the development of OCD
are rapid growth and trauma to the joint. Indirect factors affecting
rapid growth include nutrition, hormones, and genetic predisposition
to rapid growth and large size. Indirect influences that may lead
to increased trauma to the joint include conformation and behavior,
which are also influenced by heredity. Therefore, the genetic link
for most types of OCD is considered to be indirect, that is, an
inherited tendency. Certain sites for OCD lesions, such as the elbow,
appear to have a greater direct genetic contribution and a higher
heritability than other sites, such as the shoulder. The most important
contributing factor in OCD of the shoulder, the most common site,
is thought to be trauma. OCD can best be prevented in growing puppies
by controlling the main precipitating factors, overnutrition and
activities that could result in injury to the joints.
Because factors involved in the heritability of OCD are considered
to be indirect, and therefore not easily controlled by selection,
ABCA has no breeding recommendations for OCD at this time.
with no known heritable contribution:
Acquired Retinopathy (FMAR): This inflammatory eye disease is
common in many working breeds and is probably the most frequently
seen retinal lesion in Border Collies. Sometimes called "distemper
scars" or "worm scars", it is characterized by lesions
in the retina that can accumulate over the years, often leading
to impaired vision and sometimes leading to blindness. The
lesions have a typical "bull's eye" pattern, and tend
to be asymmetrical (affect one eye more than the other). The
age of onset and rate of progression varies greatly from individual
to individual. Males are more frequently affected than females.
The characteristics of this disease strongly suggest environmental
cause; no heritable pattern has ever been established for its occurrence.
Its pathology clearly distinguishes it from PRA, although
it is sometimes mistaken for PRA, especially in the later stages
of the disease.
summary, this brochure is meant to provide a brief description
of some common diseases, some current knowledge about their heritability
in our breed, and relevant breeding recommendations. Please remember,
diseases present in Border Collies are not limited to those discussed
here. Also remember, these recommendations are guidelines,
not restrictions. Keep track of updated and more in depth
Border Collie health and genetics information by checking the ABCA
web site at www.americanbordercollie.org .