![3DHenri=20](3D"http://www.boxerworld.com/forums/imgarticles/henri.jpg"=20)
Health testing is a very important =
part of=20
breeding boxers and more people need to be aware. This =
page=20
provides an explanation of genetic disease and =
descriptions of=20
those diseases prevalent in boxers, followed by a list =
of the=20
tests available to screen for those diseases and =
determine=20
genetic fitness for breeding.=20
The American Boxer Club=92s recommended health =
screening=20
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=20
genetic make-up (the genome) of the individual plays a =
significant role in causing a disease or condition. =
While some=20
disorders can occur as the result of spontaneous =
mutation,=20
most genetic disorders are inherited. These diseases =
are=20
heart-breaking because they can impact severely on the =
quality=20
and length of life of the affected dog - who is =
generally a=20
well-loved family member by the time the condition is=20
apparent.
The frequency of inherited conditions can be =
greatly=20
reduced through good breeding practices. For this to =
occur, we=20
need to know how the disease is inherited, how to =
identify the=20
condition as early as possible, and ways to recognize =
carriers=20
of the disease who are not clinically affected. Where =
testing=20
regimes are available, it is important that all =
potential=20
breeding stock are screened. Animals found to be =
affected by,=20
or are carriers of a disease should not used for=20
breeding.
Genetically inheritable diseases prevalent in =
boxers
- Aortic stenosis/sub-aortic stenosis
=
(AS/SAS) is=20
one of the most common heart defects occurring in =
boxers.=20
Stenosis is narrowing of the aorta, right below the =
aortic=20
valve, which forces the heart to work harder to =
supply=20
blood. Reduced blood flow can result in fainting and =
even=20
sudden death. The disease is inherited but its mode =
of=20
transmission is not known at this time. Diagnosis =
must be=20
made by a veterinary cardiologist, after detection =
of a=20
heart murmur. Breeding dogs must be properly =
screened for=20
this disease and affected dogs must not be bred =
from.=20
- Boxer cardiomyopathy
is an electrical =
conduction=20
disorder which causes the heart to beat erratically =
(to have=20
an arrhythmia) some of the time and can result in =
weakness,=20
collapse or sudden death. These arrhythmias are =
difficult to=20
detect with any certainty by listening to the heart =
with a=20
stethoscope, unless they are very frequent thus the =
first=20
sign of the disease may be fatal. Cardiomyopathy is =
a=20
genetically inheritable condition with devastating =
results.=20
Because a dog cannot be cleared of cardiomyopathy by =
a=20
routine veterinary examination and the disease may =
not show=20
itself until after a dog reaches breeding age, it is =
important that all breeding stock are properly =
screened for=20
this disease.
Boxer cardiomyopathy is a distinct disease from =
the=20
dilated cardiomyopathy common in some other breeds. =
Other=20
names for BCM are Boxer Arrythmic Cardiomyopathy =
(BAC),=20
Familial Ventricular Arrhythmia (FVA) and =
Arrhythmogenic=20
Right Ventricular Cardiomyopathy =
(ARVC).
- Hip dysplasia
is an inheritable =
malformation of=20
the hip joint leading to osteoarthritis. The =
hip=20
joint is a ball and socket joint, where the top of =
the thigh=20
bone (femur) fits into a socket in the pelvis. The =
bones are=20
held in place by ligaments. Hip dysplasia occurs =
when the=20
socket is poorly formed or the ligaments are loose, =
enabling=20
the ball of the femur to subluxate =96 to slide part =
way out=20
of its socket. Over time this causes degeneration of =
the=20
joint (osteoarthritis) and the dog suffers pain and =
becomes=20
weak and lame in the hind end. Hip dysplasia is a=20
progressive disease, meaning that it becomes worse =
with=20
time.
Hip dysplasia has polygenic inheritance, meaning =
it is=20
caused by the inheritance of multiple genes. It is =
not yet=20
known how many, or which genes are involved. Factors =
that=20
can make the disease worse include excess weight, =
excess or=20
prolonged exercise before maturity, a fast growth =
rate, and=20
high-calorie or supplemented =
diets.
describes an inactive =
thyroid=20
gland which can be responsible for such conditions =
as=20
epilepsy, alopecia or hair loss, obesity, lethargy,=20
hyperpigmentation, pyoderma and other skin =
conditions. While=20
not considered life threatening, the quality of life =
for a=20
dog suffering from hypothyroidism is much reduced. =
- Corneal dystrophy
=
is an=20
inherited abnormality that affects one or more =
layers of the=20
cornea. Both eyes are usually affected, although not =
necessarily symmetrically. Chronic or recurring =
shallow=20
ulcers may result, depending on the corneal layers =
affected.=20
- Demodectic mange
. The demodex =
mite lives=20
on the skin of all dogs, and is passed to puppies by =
their=20
dam. In healthy dogs, this mite causes no problems. =
However,=20
demodectic mange can occur when a dog has a weakened =
or=20
compromised immune system. The American Academy of=20
Veterinary Dermatology passed a resolution in 1983=20
suggesting that all dogs that develop generalised =
demodex=20
should be neutered or spayed as there is a genetic =
link to=20
the development of generalised demodectic mange. =
Demodectic mange can occur in localised form, =
which is=20
characterised by a few spots that do not itch. These =
patchs=20
usually appear on head, neck and fore limbs. Ninety =
percent=20
of those puppies that develop localised demodex will =
heal on=20
their own. Ten percent of those puppies will go on =
to have=20
generalised demodex.
- Cancer. Boxers are particularly =
prone to=20
the development of mast cell tumours, lymphoma and =
brain=20
tumours. White boxers, and coloured boxers with =
white=20
markings should be protected from the sun as they =
are liable=20
to develop skin cancer if allowed to burn. =
- Bloat
or Gastric dilatation-volvulus =
(GDV) is a=20
very serious condition that occurs when the stomach =
becomes=20
distended with air, and then twists on itself while =
dilated.=20
This interferes with the blood supply digestive =
organs,=20
blocks the passage of food, thus leading to worse =
bloat. The=20
distended stomach impedes the normal return of blood =
to the=20
heart, causing a decrease in blood pressure and =
drastically=20
reduced cardiac output. Blood/oxygen-deprived =
tissues start=20
to die, releasing toxins into the blood stream which =
among=20
other adverse effects, cause serious disturbances in =
heart=20
rhythms (cardiac arrhythmias). Dogs affected by =
bloat can=20
die within hours.
Dogs most susceptible to bloat are the large,=20
deep-chested breeds, in whom the stomach appears to =
be more=20
mobile within the abdomen. Risk factors are: =
hereditary=20
predisposition, over-eating (large meals), rapid =
eating,=20
raised feeders, pre-moistening of dry food preserved =
with=20
citric acid, feeding dry food with a fat in the top =
four=20
ingredients. The risk of bloat increases with age. =
Feeding a=20
food with a rendered meat ingredient, inclusive of =
bone, in=20
the first four ingredients decreases the risk =
of=20
bloat.
The Purdue veterinary research team, who =
conducted a=20
research study in 2000 into the risk factors =
associated with=20
bloat concluded these are the things you can do to =
help=20
prevent bloat:
a.. The strongest =
recommendation to=20
prevent GVD (bloat) should be to not breed a dog =
that has a=20
first degree relative that has had bloat. This =
places a=20
special responsibility on an owner to inform the =
breeder=20
should their dog bloat.
b.. Do not raise the =
feeding=20
dish.
c.. SLOW the dog's speed of =
eating.
- Allergies. Boxers are rather prone =
to=20
allergies, which can be environmental or food =
related. These=20
often translate into itchy, scaly and sometimes =
infected=20
skin. Boxers do not tend to do well on foods that =
have a=20
high grain content, particularly those including =
corn, wheat=20
or beet pulp.
- Deafness. About 20% of white =
boxers are=20
deaf, due to their lack of pigmentation and =
suppression of=20
blood supply to the cochlea (inner ear). White =
boxers should=20
not be bred since the genes responsible for deafness =
in=20
whites are inheritable. Breeding dogs that carry the =
extreme=20
white spotting gene (white boxers have two copies of =
this=20
gene, see http=
://www.boxerworld.com/forums/view_boxer-coat-colour.htm)=20
will cause pigment dilution in all offspring and =
increase=20
the incidence of deafness throughout the breed. =
Tests available to screen for serious genetic =
diseases and=20
which should be undertaken on all breeding boxers
Holter Monitor: A 24-hour EKG =
(electrocardiogram) that=20
tests for the presence of PVCs (Premature Ventricular=20
Contractions). This test screens for Boxer Arrythmic=20
Cardiomyopathy, and should be repeated yearly. There =
is, at=20
this time, no set number of PVCs that would be =
considered=20
"affected" with BAC. A zero or low number of PVCs does =
not=20
mean that the dog is free of BAC, it only means that =
the dog=20
was not exhibiting PVCs during that 24-hour period. =
However,=20
consistent zero/low readings on yearly Holtering would =
indicate a higher possibility that the dog is not =
affected=20
with BAC.
For more information, please visit http://www.americanboxerclub.org/healthtbc.html=20
and read these articles: Reports From The Health And =
Research=20
Committee, May 2000; Information on Boxer =
Cardiomyopathy;=20
Report and Article by Dr. Meurs; Article on Boxer=20
Cardiomyopathy; Information on Holter =
monitoring.
Doppler Echocardiogram: An ultrasound of the =
heart that=20
detects abnormal flow velocities and allows for the =
diagnosis=20
and quantification of the severity of Aortic Stenosis. =
A clear=20
Doppler after the dog is 24 months of age is =
considered=20
conclusive (the dog does not have AS). Some studies =
show that=20
Aortic Stenosis is a polygentic (cause by several =
genes)=20
disease, so two clear parents can produce affected=20
offspring.
Cardiac Auscultation: A stethoscopic =
examination of the=20
heart that detects murmurs that may be indicative of =
AS.=20
According to the UK Breed Council Control Scheme, a =
dog that=20
is found to have no murmur or a Grade 1 murmur upon=20
auscultation after 12 months of age is considered =
normal and=20
acceptable for breeding.
OFA Heart: The OFA will certify dogs as =
"normal" if=20
they are found, upon ausculatation after 12 months of =
age, to=20
be without a cardiac murmur, or with an innocent heart =
murmur=20
that is found to be otherwise normal by virtue of an=20
echocardiographic examination which includes Doppler =
studies.=20
Screening can be done by a general practice =
veterinarian, a=20
specialist, or a cardiologist. Submission of results =
is=20
voluntary. OFA Heart testing may detect Aortic =
Stenosis,=20
although mild cases may go unnoticed if auscultation =
is=20
performed by a general practice vet. It will not =
detect Boxer=20
Arrythimic Cardiomyopathy.
OFA has developed a =
database=20
registry for Holter Monitor results for the Boxer =
breed.=20
Submission of results is voluntary and they are=20
confidential.
For more information on all OFA =
tests, please=20
visit http://www.offa.org/
**All heart testing should be performed by a=20
board-certified veterinary cardiologist.**
OFA Hips (Orthopedic Foundation for Animals =
Inc): An=20
X-ray of the pelvic joint to screen for hip dysplasia. =
Ratings=20
of "Excellent," "Good," or "Fair" are considered to be =
free of=20
HD. One view is taken, the dog is commonly sedated or=20
anesthetized but this is not required, and submission =
of=20
results is voluntary. The X-rays must be taken after =
the dog=20
is 24 months of age. There are several other factors =
that=20
influence the expression of HD, including diet and=20
environment, and two clear parents can produce =
dysplastic=20
puppies.
PennHip (University of Pennsylvania Hip =
Improvement=20
Program): An X-ray of the pelvic joint to screen for =
hip=20
dysplasia. Laxity of the hips is evaluated and =
compared to the=20
breed average (the Boxer breed average is .48 laxity). =
Three=20
views are taken, the dog must be sedated or =
anesthetized, and=20
submission of results is mandatory. PennHip X-rays can =
be=20
taken as early as 16 weeks, although most feel a =
definitive=20
rating should wait until the dog is older.
OFA Thyroid: A blood test to detect autoimmune=20
thyroiditis. Annual testing through 4 years of age is=20
recommended, after that, testing every other year =
should=20
suffice. A negative at any one time will not guarantee =
that=20
the dog will not develop thyroiditis. Most vets do not =
perform=20
a full thyroid panel - as a result, there are only six =
laboratories that are approved for OFA thyroid =
certification:=20
the veterinary laboraties at Michigan State =
University,=20
Cornell University, University of Guelph, University =
of=20
Minnesota, University of California - Davis, and Texas =
A&M=20
University.
CERF (Canine Eye Registration Foundation) =
testing=20
screens for heritable eye diseases such as PRA =
(Progessive=20
Retinal Atrophy). Results are kept in a centralized, =
national=20
registry. Testing must be performed by a member of the =
American College of Veterinary Ophthalmologists. =
Submission of=20
results is mandatory but confidential. CERF screening =
is=20
repeated yearly.
If you want to discuss about these =
topics,=20
visit our
Boxer=20
Health and Puppy=20
Matters forums.
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