Health testing is a very important part of breeding boxers and more people
need to be aware. This page provides an explanation of genetic disease and
descriptions of those diseases prevalent in boxers, followed by a list of the
tests available to screen for those diseases and determine genetic fitness for
The American Boxer Club’s recommended health screening programme for
breeding boxers can be viewed at http://www.americanboxerclub.org/health-screening.html
What is a genetic disease?
A genetic disorder is one in which an abnormality in the genetic make-up (the
genome) of the individual plays a significant role in causing a disease or
condition. While some disorders can occur as the result of spontaneous mutation,
most genetic disorders are inherited. These diseases are heart-breaking because
they can impact severely on the quality and length of life of the affected dog -
who is generally a well-loved family member by the time the condition is
The frequency of inherited conditions can be greatly reduced through good
breeding practices. For this to occur, we need to know how the disease is
inherited, how to identify the condition as early as possible, and ways to
recognize carriers of the disease who are not clinically affected. Where testing
regimes are available, it is important that all potential breeding stock are
screened. Animals found to be affected by, or are carriers of a disease should
not used for breeding.
Genetically inheritable diseases prevalent in boxers
- Aortic stenosis/sub-aortic stenosis
(AS/SAS) is one of the most
common heart defects occurring in boxers. Stenosis is narrowing of the aorta,
right below the aortic valve, which forces the heart to work harder to supply
blood. Reduced blood flow can result in fainting and even sudden death. The
disease is inherited but its mode of transmission is not known at this time.
Diagnosis must be made by a veterinary cardiologist, after detection of a heart
murmur. Breeding dogs must be properly screened for this disease and affected
dogs must not be bred from.
- Boxer cardiomyopathy is an electrical conduction disorder which
causes the heart to beat erratically (to have an arrhythmia) some of the time
and can result in weakness, collapse or sudden death. These arrhythmias are
difficult to detect with any certainty by listening to the heart with a
stethoscope, unless they are very frequent thus the first sign of the disease
may be fatal. Cardiomyopathy is a genetically
inheritable condition with devastating results. Because a dog cannot be
cleared of cardiomyopathy by a routine veterinary examination and the disease
may not show itself until after a dog reaches breeding age, it is important
that all breeding stock are properly screened for this disease.
Boxer cardiomyopathy is a distinct disease from the dilated cardiomyopathy common in some other breeds. Other names for BCM are Boxer Arrythmic Cardiomyopathy (BAC), Familial Ventricular Arrhythmia (FVA) and Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC).
- Hip dysplasia is an inheritable malformation of the hip joint
leading to osteoarthritis. The hip joint is a ball and socket joint,
where the top of the thigh bone (femur) fits into a socket in the pelvis. The
bones are held in place by ligaments. Hip dysplasia occurs when the socket is
poorly formed or the ligaments are loose, enabling the ball of the femur to
subluxate – to slide part way out of its socket. Over time this causes
degeneration of the joint (osteoarthritis) and the dog suffers pain and
becomes weak and lame in the hind end. Hip dysplasia is a progressive disease,
meaning that it becomes worse with time.
Hip dysplasia has polygenic inheritance, meaning it is caused by the
inheritance of multiple genes. It is not yet known how many, or which genes
are involved. Factors that can make the disease worse include excess weight,
excess or prolonged exercise before maturity, a fast growth rate, and
high-calorie or supplemented diets.
describes an inactive thyroid gland which can be
responsible for such conditions as epilepsy, alopecia or hair loss, obesity,
lethargy, hyperpigmentation, pyoderma and other skin conditions. While not
considered life threatening, the quality of life for a dog suffering from
hypothyroidism is much reduced.
- Corneal dystrophy is
an inherited abnormality that affects one or more layers of the cornea. Both
eyes are usually affected, although not necessarily symmetrically. Chronic or
recurring shallow ulcers may result, depending on the corneal layers affected.
- Demodectic mange. The demodex mite lives on the skin of all
dogs, and is passed to puppies by their dam. In healthy dogs, this mite causes
no problems. However, demodectic mange can occur when a dog has a weakened or
compromised immune system. The American Academy of Veterinary Dermatology
passed a resolution in 1983 suggesting that all dogs that develop generalised
demodex should be neutered or spayed as there is a genetic link to the
development of generalised demodectic mange.
Demodectic mange can occur in localised form, which is characterised by a
few spots that do not itch. These patchs usually appear on head, neck and
fore limbs. Ninety percent of those puppies that develop localised demodex
will heal on their own. Ten percent of those puppies will go on to have
- Cancer. Boxers are
particularly prone to the development of mast cell tumours, lymphoma and
brain tumours. White boxers, and coloured boxers with white markings should
be protected from the sun as they are liable to develop skin cancer if
allowed to burn.
- Bloat or Gastric dilatation-volvulus (GDV) is a very serious
condition that occurs when the stomach becomes distended with air, and then
twists on itself while dilated. This interferes with the blood supply
digestive organs, blocks the passage of food, thus leading to worse bloat. The
distended stomach impedes the normal return of blood to the heart, causing a
decrease in blood pressure and drastically reduced cardiac output.
Blood/oxygen-deprived tissues start to die, releasing toxins into the blood
stream which among other adverse effects, cause serious disturbances in heart
rhythms (cardiac arrhythmias). Dogs affected by bloat can die within hours.
Dogs most susceptible to bloat are the large, deep-chested breeds, in
whom the stomach appears to be more mobile within the abdomen. Risk factors
are: hereditary predisposition, over-eating (large meals), rapid eating,
raised feeders, pre-moistening of dry food preserved with citric acid,
feeding dry food with a fat in the top four ingredients. The risk of bloat
increases with age. Feeding a food with a rendered meat ingredient,
inclusive of bone, in the first four ingredients decreases the risk
The Purdue veterinary research team, who conducted a research study in
2000 into the risk factors associated with bloat concluded these are the
things you can do to help prevent bloat:
a.. The strongest recommendation to prevent GVD (bloat) should be to not
breed a dog that has a first degree relative that has had bloat. This places
a special responsibility on an owner to inform the breeder should their dog
b.. Do not raise the feeding dish.
c.. SLOW the dog's speed of eating.
- Allergies. Boxers are
rather prone to allergies, which can be environmental or food related. These
often translate into itchy, scaly and sometimes infected skin. Boxers do not
tend to do well on foods that have a high grain content, particularly those
including corn, wheat or beet pulp.
- Deafness. About 20% of
white boxers are deaf, due to their lack of pigmentation and suppression of
blood supply to the cochlea (inner ear). White boxers should not be bred
since the genes responsible for deafness in whites are inheritable. Breeding
dogs that carry the extreme white spotting gene (white boxers have two
copies of this gene, see http://www.boxerworld.com/forums/view_boxer-coat-colour.htm)
will cause pigment dilution in all offspring and increase the incidence of
deafness throughout the breed.
Tests available to screen for serious genetic diseases and which should be
undertaken on all breeding boxers
Holter Monitor: A 24-hour EKG (electrocardiogram) that tests for the
presence of PVCs (Premature Ventricular Contractions). This test screens for
Boxer Arrythmic Cardiomyopathy, and should be repeated yearly. There is, at this
time, no set number of PVCs that would be considered "affected" with
BAC. A zero or low number of PVCs does not mean that the dog is free of BAC, it
only means that the dog was not exhibiting PVCs during that 24-hour period.
However, consistent zero/low readings on yearly Holtering would indicate a
higher possibility that the dog is not affected with BAC.
For more information, please visit http://www.americanboxerclub.org/healthtbc.html
and read these articles: Reports From The Health And Research Committee, May
2000; Information on Boxer Cardiomyopathy; Report and Article by Dr. Meurs;
Article on Boxer Cardiomyopathy; Information on Holter monitoring.
Doppler Echocardiogram: An ultrasound of the heart that detects abnormal
flow velocities and allows for the diagnosis and quantification of the severity
of Aortic Stenosis. A clear Doppler after the dog is 24 months of age is
considered conclusive (the dog does not have AS). Some studies show that Aortic
Stenosis is a polygentic (cause by several genes) disease, so two clear parents
can produce affected offspring.
Cardiac Auscultation: A stethoscopic examination of the heart that
detects murmurs that may be indicative of AS. According to the UK Breed Council
Control Scheme, a dog that is found to have no murmur or a Grade 1 murmur upon
auscultation after 12 months of age is considered normal and acceptable for
OFA Heart: The OFA will certify dogs as "normal" if they are
found, upon ausculatation after 12 months of age, to be without a cardiac
murmur, or with an innocent heart murmur that is found to be otherwise normal by
virtue of an echocardiographic examination which includes Doppler studies.
Screening can be done by a general practice veterinarian, a specialist, or a
cardiologist. Submission of results is voluntary. OFA Heart testing may detect
Aortic Stenosis, although mild cases may go unnoticed if auscultation is
performed by a general practice vet. It will not detect Boxer Arrythimic
OFA has developed a database registry for Holter Monitor results for the Boxer
breed. Submission of results is voluntary and they are confidential.
For more information on all OFA tests, please visit http://www.offa.org
**All heart testing should be performed by a board-certified veterinary
OFA Hips (Orthopedic Foundation for Animals Inc): An X-ray of the pelvic
joint to screen for hip dysplasia. Ratings of "Excellent,"
"Good," or "Fair" are considered to be free of HD. One view
is taken, the dog is commonly sedated or anesthetized but this is not required,
and submission of results is voluntary. The X-rays must be taken after the dog
is 24 months of age. There are several other factors that influence the
expression of HD, including diet and environment, and two clear parents can
produce dysplastic puppies.
PennHip (University of Pennsylvania Hip Improvement Program): An X-ray of
the pelvic joint to screen for hip dysplasia. Laxity of the hips is evaluated
and compared to the breed average (the Boxer breed average is .48 laxity). Three
views are taken, the dog must be sedated or anesthetized, and submission of
results is mandatory. PennHip X-rays can be taken as early as 16 weeks, although
most feel a definitive rating should wait until the dog is older.
OFA Thyroid: A blood test to detect autoimmune thyroiditis. Annual
testing through 4 years of age is recommended, after that, testing every other
year should suffice. A negative at any one time will not guarantee that the dog
will not develop thyroiditis. Most vets do not perform a full thyroid panel - as
a result, there are only six laboratories that are approved for OFA thyroid
certification: the veterinary laboraties at Michigan State University, Cornell
University, University of Guelph, University of Minnesota, University of
California - Davis, and Texas A&M University.
CERF (Canine Eye Registration Foundation) testing screens for heritable
eye diseases such as PRA (Progessive Retinal Atrophy). Results are kept in a
centralized, national registry. Testing must be performed by a member of the
American College of Veterinary Ophthalmologists. Submission of results is
mandatory but confidential. CERF screening is repeated yearly.
If you want to discuss about these topics, visit our Boxer