I met with Dr. Sandra Minors (Dip ACVIM-Cardiology), at the Bronte Road Animal Hospital, Oakville, Ontario in July, just after our Canadian National Specialty to learn more about the incicdence of hereditary heart problems in Rottweilers. I also spoke with the cardiology resident working under Dr. Michael O'Grady (Dip ACVIM-Cardiology) at the Ontario Veterinary College in early August, then was fortunate enough to speak with Dr. Larry Tilley (arguably the pre-eminent verterinary cardiologist in Narth America, if not the world!) at a cardiology seminar I attended in Toronto, August 16, 1997. After speaking with these veterinary cardiologists it appears that we (Rottweiler Breeders) fall far behind breeders of Golden Retreivers, Newfoundlands, Labrador Retrievers, Dobermann Pinchers and Boxers in the testing of our dogs. The primary problem seen in our breed remains sub-aortic stenosis (SAS), but both Dr. Minors and Dr. O'Grady have reported several familial lines with an alarming number of cases of hypertrophic cardiomyopathy (HCM). All three cardiologists noted that our breed is now second only to Golden Retrievers in the number of diagnosed cases of SAS, and feel that if we do not start getting the average breeder to obtain cardiac clearance prior to breeding, healthy hearts in our breed will go the way of the DoDo bird!X Both Dr. Minors and Dr. O'grady's resident noted that they have a hard time finding a Boxer without a murmur now, and Goldens are almost as bad!.....Rottweilers will be next!!!!!!
What can we do to make our membership understand the enormity and seriousness of this problem? I, myself, called up a few breeders and stud dog owners listed in The Rottweiler Quarterly, and greater then 95% of those called either did not understand why they should be checking their dogs' hearts or they did not check for heart problems "because there were no heart problems in their lines". If the knowledgeable guardians of our breed refuse to check for cardiac problems, how can we bully and berate those who through sheer ignorance do not screen hips, elbows, thyroid, eyes, etc., etc., prior to breeding? I myself had a litter in which nine of the ten pups had cardiac problems and five were humanely destroyed when they failed to thrive. I would rather have a dysplastic dog, a hypothyroid dog, a Von Willdebrands carrier or a dog with entropion to tell you the truth......SAS and HCM both have the very real potential to kill our dogs at a young ae with no warning whatsoever, and I feel this is and will remain the most pressing health issue affectin our breed.
Dr. Catherine A. Priddle DVM
Aortic stenosis is characterized by a narrowing of the aortic valve, the outflow tract from the heart's left ventricle. This causes a partial obstruction of blood flow into the circulation, increasing the heart's workload and in turn causing an increase in the thickness of the left ventricular wall. This "left ventricular concentric hypertrophy" results in decreaed left ventricular distensibility and an increase in heart dysrhythmias. Aortic stenosis may be subvalvular, valvular or supravalvular, depending on where the constriction is located. Subvalvular, or Sub Aortic Stenosis (SAS) is most common.
Most commonly, puppies are presented to a veterinarian for their first series of vaccinations and a heart murmur is noted as an incidental finding, as the affected puppy is without clinical symptoms of cardiac disease. However, in severe cases, syncope (fainting) or sudden death may occur. For those of you who may be interested, the murmur is systolic, with the Point of Maximal Intensity (PMI) over the left heart base. The murmur presented may be of varying intensity, from low (grade 1 or 2 out of 6) to moderate or severe (grade 3/6 or greater). These murmurs can be confused with "innocent", or non disease related murmurs, which usually occur as well over the left ventricular outflow tract, are of low intensity (grade 1/6 or 2/6) and occur early in systole (prosystole). Innocent murmurs, however, should resolve by six months of age. Some authors believe that similar innocent heart murmurs may also occur in adults, particularly in large and giant breeds and/or very athletic dogs.
Research has indicated that aortic stenosis is a progressive disease, but the rate of progression varies with maturity. In immature/growing dogs the rate of progression is increased, while progression is restricted to a very slow rate in mature/adult dogs. It has been reported that if a dog with aortic stenosis lives to be greater then three years of age, it USUALLY does not have aortic stenosis that is severe enough to affect left ventricular performance.
Diagnosis (and most accurate prognosis) is acheived either through Doppler echocardiography, which is a safe, non-invasive procedure or via cardiac catheterization. On Doppler, the velocity of bloodflow through the aorta is measured, and it has been reported that if the bloodflow velocity is less than 4 metres/second at maturity, the dog USUALLY will have a normal quality and quantity of life. However, if the bloodflow velocity is measured to be greater than 5 metres/second, the dog will USUALLY succumb to the disease. These testing procedures in our dogs are very important, as an affected dog's electrocardiogram (EKG) is usually normal and radiographs are frequently normal in affected dogs as well.
In order to attempt to learn more about the hereditary
nature of this disease, it is important that we all have our dogs tested
by a board-certified cardiologist prior to breeding. Although the abscence
of a heart murmur DOES NOT mean that a particular dog is not affected,
or that he/she does not carry this disease, and therefore, the ability
to pass it on to successive generations, it DOES afford us a low cost,
non-invasive screening test. The cardiologist will listen to your dog's
heart in a quiet setting at rest and then again after exercise. Dogs who
have a heart murmur are recommended to undergo further testing, specifically
Doppler echocardiography. The Orthopedic Foundation for Animals (OFA),
now has a cardiac registry and will catagorize dogs as;
1) Normal-congenital heart disease not evident,
2) Equivocal-congenital heart disease cannot be diagnosed nor excluded or
3) Abnormal-examination indicative of congenital heart disease. It is important that we read the ENTIRE cardiac certification number, as the OFA is allowing non-specialist general practitioners to certify dogs, and only by examining the entire certification number can you differentiate between those dogs examined by a board-certified veterinary cardiologist and those certified by a general practitioner. The OFA certification number of a cardiologist cleared dog will have a "C" at the end of the number combination, while the number of a practitioner cleared dog will have a "P". For example, O-CA123/45M/P-T would be Rottweiler-Cardiac number 123/age 45 months/PRACTITIONER cleared-Tatooed, whereas RO-CA123/45M/C-T would be the identical dog with a CARDIOLOGIST cleared OFA certification number.
I, myself, have a dog that three general practitioners
(including myself!)auscultated and would have classified free of a heart
murmur. However, a board-certified veterinary cardiologist heard a soft
(grade 1-2/6) murmur upon examination and the dog has been classed (for
now) as "equivocal" by the OFA. After consulting with this cardiologist
and others, I have decided to breed this dog now (he is 2 years old), check
all resulting puppies at 6-9 months of age and have him rechecked at 4-5
years of age (maturity). I will also have his heart checked by a cardiologist
post mortem, so the outflow tract, chambers size, heart wall thickness,
etc. can all be measured. Will it be difficult to remove the heart of a
dog I love so dearly? YES...but I see it as a greater act of love, one
last thing he (and I) can do for this magnificent breed.
Questions/Comments/Discussion always welcome!
Dr. Cathy Priddle
RCC Health Committee
Heartworms have been common in the south eastern coastal
states for more than 50 years. During the last 20 they have become a real
threat to our Rottweilers. They have slowly spread inland from the East
coast and now few states, if any, are free from heartworms. Hundreds of
dogs die every year from this insidious deadly parasite.
The heartworm depends on both the dog and the mosquito in order for it to continue. Adult heartworms are found in the right ventrical of the heart and adjacent vessels. The larvae produced from the adult female heartworm is called microfilaria. These microscopic creatures will circulate through your dog's blood vessels until a feeding mosquito ingests them. Once inside the host mosquito, the microfilaria will develop into its second and third stages. This takes about 2 to 3 weeks. It is at the third stage, when the mosquito bites your Rottie or someone elsets dog, the larvae is then deposited back into the unfortunate canine. Next the larvae moves to the fat or muscle cells underneath the skin where they then molt and again make a transformation a fourth and fifth time.
About three months later young adult heartworms begin traveling directly to the right ventrical of the heart where they will take up residence and mature. About 6 to 7 months later, the female heartworms begin producing new microfilaria, and so on, and so on and........
Because most heartworms are very slow in maturing, your Rottweiler may not exhibit signs of the infestation until it is already in the advanced stages. Symptoms could be coughing, loss of appetite, difficulty breathing while exercising and possible general lethargy. At times signs can include vomiting, diarrhea, and possible jaundice (where normal pink parts of a dog's gums and eyes appear yellow). Once these signs are present, however, the heartworm disease is usually so advanced that successful treatment is greatly reduced. Never wait more than a couple of days if you notice any of the above symptoms in your Rottie.
There is another form of heartworm disease that is even more serious than the one already mentioned. It is called post caval syndrome. Dogs that have developed this syndrome will often have severe breathing difficulty by the time a veterinarian sees them. Their jugular veins will pulse with every heartbeat. For a dog with post caval syndrome to survive it should have immediate surgical removal of as many of the worms as possible directly through the jugular vein. The means of diagnosis is via a blood test. Once it has been determined your Rottie is free of any deadly heartworms he/she can be placed on a preventative treatment. Giving a dog preventatives that is already infected with heartworms can produce serious problems. There are different ways to administer preventatives, some that must be given daily and others monthly. Be sure to discuss this with your local veterinarian, but above all be sure to qet sour Rottweiler tested and on a preventative treatment. This is a case where really an ounce of prevention, even if daily, will prevent what could be disaster for your best friend. Treatment of heartworm disease is not only expensive, but very dangerous to your dog.
More and more veterinarians across the countrv are recommendinq that all dogs be kept on heartworm preventative year round.
The OFA is the Orthopediac Foundation for Animals, Inc.
and is responsible for maintaining the hip and elbow registries, among
others, for dogs in North America. At the OFA a panel of three board-certified
veterinary radiologists will read your dog's pelvic radiograph and give
the dog a rating of Excellent, Good or Fair hip structure, all of which
are permissible to breed. They will also examine your dog's elbows via
standardized XRay procedures, and rate him "Clear" of elbow dysplasia.
As many of you are probably aware, the Ontario Veterinary College radiologists
will also read hip and elbow XRays amd will grade them "Clear", but these
ratings are not standardized along OFA guidelines, as the OVC will grade
hips at 18 months of age (versus 24 months for OFA), and they do not have
the grading system(s) of the OFA.
Canine Hip Dysplasia (CHD) is an inherited trait involving multiple gene factors. CHD is a developmental disease, all dogs are apparently born with normal hips, but, in affected individuals, the radiographic signs become evident within several months to years. The OFA reports that the accuracy of diagnosis is approximately 95% at 24 months of ge. Because OFA data is drawn from breeders submitting radiographs that have been pre-screened by their own vets, this data is biased toward normal (i.e. if your vet told you your dog was dysplastic, you would not likely send the XRay into the OFA, so they receive a greater percentage of normals then are actually present in the population). This presents a scary picture in our breed. OFA results from January 1974 to July 1991 show that 37,497 Rottweilers were evaluated and that 23.3% were dysplastic!! ...Imagine the numbers who were not sent in because their own vets diagnosed CHD at the time the XRay was taken, in addition to the numbers that were never even radiographed!! I would hazard a guess that probably about 40% of our breed is affected by this crippling disease!!
The OFA suggests that we, as responsible breeders should only breed dogs with normal hips to dogs with normal hips. Prospective breeders and buyers should check OFA numbers with the registry and ask to see the OFA certificate. If an OFA number canot be verified assume the dog to be dysplastic until proven otherwise! Preliminary evaluations can be done as early as 4-5 months of age with 85-90% accuracy. Please remind your vet that when taking the XRay anesthesia is recommended, and for bitches the OFA recommends radiographing 3-4 weeks before or after a heat period to prevent any false positives due to hormonal effects of the estrus cycle. The OFA further states that there are no environmental factors which cause CHD, there is no evidence that vitamin C is beneficial in reducing or preventing CHD, high caloric intake resulting in rapid growth and increased weight gain may exacerbate dysplastic hips, but will not create hip dysplasia, running, jumping, slick floors, etc. will not cause hip dysplasia, and that previous injuries to the legs or hip structure can be recognized on the XRays and are taken into account when evaluating hip status.
The OFA elbow registry is for dogs 24 months of age or greater, and is a standardized evaluation of the elbow joint for ununited anconeal process, fragmented coronoid process, osteochondrosis, or any combination thereof which would constitute elbow dysplasia. Over 70 breeds have been evaluated for elbow dysplasia by the OFA, and positive results have been found in 20 breeds. Rottweilers are currently ranked fifth on the affected breeds list. As of December 31, 1991, 402 Rottweilers have been evaluated, with 38.8% showing signs of elbow dysplasia. Again, these results are biased toward normal, pushing our breed's actual affected percentage up close to the 50% range!! Certainly something to ponder...whether breeding or buying!
Speaking as a fellow breeder, I cannot diagree with any of the above mentioned 'scientific' results, but I will admit to you that I take every precaution possible to prevent CHD and elbow/shoulder problems in my dogs. As well as breeding only unaffected dogs and buying pups only from unaffected parents, I also line my whelping box with indoor/outdoor carpeting and flannel sheets rather then newspaper for better traction, I try not to house dogs on cement any more then is absolutely necessary, I carry puppies up and down stairs for as long as my back can handle it, there are no fat dogs (especially puppies!) at my house (which my handler keeps complaining to me about!), dogs are not allowed to jump into the back of the truck (for example) until after 24 months of age, and no forced exercise is done (i.e. bicycling) until they are certified. I prelim all my dogs at approximately one year of age, if they are not CHD free at that age, I would spay/neuter and place them in a suitable home depending on the severity of the disease. I radiograph the dog's elbows at 24 months of age and send the radiograph to the OFA for evaluation at the same time as the hips are done.
I shall give approximate costs (from the OVMA Fee Guide for Small Animal Procedures 1993) involved in having a dog radiographed and submitted to the OFA for CHD evaluation.
1) Anesthesia & Reversal: $60.00
2) Radiograph: $47.80
3) One Half Day Hospitalization: $16.90
4) Courier to OFA: $30.00
5) OFA Evaluation Fee: $25.00 (US Funds).
Many vets have a standard fee for radiographs sent to the OFA which may make this slightly less expensive, but prices will vary. The elbows can be radiographed at the same time, with the additional charge of two XRay films. The OFA charges $15.00 to prelimhips or evaluate elbows and $25.00 to evaluate hips and elbows on one dog submitted at the same time.
"A stitch in time saves nine" and "Penny wise, pound foolish" certainly applies here to breeders who complain that they can't afford to have their dogs hips and/or elbows XRayed prior to breeding, or that they just get their own vet to read the radiographs because the OFA is too expensive. I, personally, cannot afford the loss of respect in the dog community, the emotional and mental anguish I would suffer by producing dogs with defects that I could have prevented (or at the very least took every precaution available to attempt to prevent), and I cannot afford to replace puppies or refund purchase prices because my dogs are not healthy. PLEASE PEOPLE, MAKE USE OF THESE REGISTRIES PRIOR TO BUYING OR BREEDING, FOR THE BETTERMENT OF THE BREED (afterall, isn't that what we are all striving toward??). .