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Health Matters!
The HSDAA Health Committee (Bobbi Lowry RN, Chair, Joanne V Baldwin DVM, Margie Staniszeski RN) presents an overview of Silk Dog health, past, present, and future!
What follows is a brief explanation of the various health considerations which are carefully monitored by HSDAA.
For information on health testing in common use by Silk Dog breeders and owners, please visit Health Testing ABCs.
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It is the mission and responsibility of the HSDAA Health committee to educate breeders and the general public about health issues and to encourage the intelligent, careful breeding of sound, healthy puppies so that prospective owners have a choice when seeking a puppy...they have the option of choosing a puppy from parents who are completely health tested, who have passed a conformation evaluation, and which are certified free of chondrodysplasia.
The Havana Silk Dog has been developed by careful selection from an ancestral gene pool in common with the Havanese. There are a number of health issues that are all too common in this gene pool and the goal of the HSDAA breeders is to continue selecting away from these historical issues which include cataracts, chondrodysplasia, patellar luxation, hip and/or elbow dysplasia, liver abnormalities, cardiac abnormalities, and deafness. Other conditions with lower incidence that have been found include, but are not limited to, seizures, kidney dysplasia, hypothyroidism and skin problems.
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A cataract is an opacity of the lens of the eye. Cataracts can develop early, or late, become mature, causing blindness or be slow in growth and not progress to blindness. They can appear in different locations within the lens and affect one or both eyes. Surgical correction of cataracts (removal) is best done before cataracts become mature. Although cataracts do not appear to be an issue in the Havana Silk Dog, HSDAA recommends annual CERF exams for all HSDs. It is only through continued monitoring that we can be sure that we have left this devastating health issue behind.
To this end, the Havana Silk Dog has its own database with CERF so that we can track any ocular problems which may be found. Owners and breeders are encouraged to report any health issues which may arise to the Health Committee so that we can follow any trends in the breed.
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| Cross-section of the eye |
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| Chondrodysplasia in the Havanese |
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Chondrodysplasia does not appear to be an issue in the Havana Silk Dog due to rigorous screening and elimination of any affected dog from the gene pool. Literally, this is "faulty cartilage", and it can be manifested in a variety of ways. It can be characterized by premature closure of the growth plates of long bones either symmetrically, or asymmetrically. This can result in short legs (dwarfism) that are straight or bowed either unilaterally or bilaterally.
An extensive research project completed at Texas A&M concluded that chondrodysplasia co-segregates with several other health issues affecting Havanese (ie cataracts, heart and liver abnormalities) so we hope that eliminating CD will also reduce, or eliminate several other issues as well. Owners and breeders are encouraged to report any suspected CD to the Health Committee so that we can build a database which will help us assess breed health.
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Patellar Luxation
Patellas (kneecaps) normally ride in a groove in the lower end of the femur (thigh bone) and is held in place by ligaments attaching it to the femur and to the tibia (shin bone.) If the patella is unstable and is able to move out of this groove, it is said to be luxating. Patellas can luxate medially or laterally, on one or both legs. The severity of the luxation is described by Grades, with Grade 1 being the most mild (the patella can be moved out of the groove with moderate pressure but returns when released.) Grade 4 is the most severe involving deviation of the legs and permanent luxation of the patella(s). Surgical correction is often recommended for Grades 3-4 as this condition can cause pain, arthritis and difficulty in movement. It is not recommended to breed dogs with this condition as it may be passed on to future generations. If an owner or breeder has a Silk Dog with patellar luxation please report it to the HSDAA Health Committee.
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Hip Dysplasia
Malformation of the hip joint can result in development of arthritis due to damage done to the articular cartilage from trauma as bones grind together because they do not fit correctly. Dysplastic dogs may, or may not, show clinical signs of lameness. All Havana Silk Dogs must have normal hips as evaluated by OFA (Orthopedic Foundation for Animals) before being granted 'certified' status so the registration process itself weeds dysplastic dogs out of the gene pool. The incidence of hip dysplasia in the Havana Silk Dog appears to be extremely low and continued testing and evaluation of breeding stock should keep it this way. While some deny that hip dysplasia is an issue in toy dogs, the breed ranked #2 in incidence of hip dysplasia at OFA is the Pug, a Toy breed. The conformation standard to which the Silk Dog is being bred (dropped croup, finer bone, etc) represents a phenotype that is less likely to develop hip dysplasia than dogs with heavier bone, flatter pelvis, and a higher tailset (ie think Pug vs Whippet.)
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Elbow dysplasia is a general term used to identify an inherited polygenic disease in the elbow of dogs. Three specific etiologies make up this disease and they can occur independently or in conjunction with one another. These etiologies include:
- Pathology involving the medial coronoid of the ulna (FCP)
- Osteochondritis of the medial humeral condyle in the elbow joint (OCD)
- Ununited anconeal process (UAP)
Elbow abnormalities have usually been associated with chondrodysplasia in Havanese and are probably the result of abnormal stress on the joint due to malformation of the forelegs, therefore are not expected to be a significant issue in the Havana Silk Dog. If you have a Silk Dog with elbow dysplasia, please report it to the Health Committee.
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There has been one confirmed case of portosystemic shunt in the Havana Silk Dog breed. The membership response to this discovery was immediate and positive. HSDAA Health representative contacted Dr Sharon Center, who is conducting a CHF funded research project to find the gene(s) responsible for liver shunts in the dog. The breeder of the puppy and the breeders/owners of numerous related dogs volunteered to submit samples for bile acids and/or DNA to Dr Center for the study. A kindred chart was made of the pup's family tree and, to date, samples from 5 generations of related dogs have been, or are being submitted.
In addition to cooperating with samples, the HSDAA membership voted to become a sponsor for Dr Center's study with an initial donation of $7000. This response is characteristic of this health conscious, pro-active club. Open sharing of information and generous support for health research is the norm at HSDAA. The incidence of HMD is not known in the Silk Dog but Dr Center maintains that it appears to be widespread in the Havanese so, we cannot assume that we left it behind. When Dr Center's research is completed, a gene test will be a most valuable tool to assure that the dogs we are producing have normal liver function.
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◊The HSDAA Health Committee recommends that breeders include liver panels in the health screening performed on dogs contributing to the gene pool so that we can assure that only dogs with normal liver function are used for breeding.◊
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Cardiac Abnormalities
The most common cardiac problem many toy breeds appears to be premature degeneration of one or more heart valves. Each side of the heart has a valve to keep blood from going backward from the ventricles to the atria. The valve between the left atrium and left ventricle is called the mitral valve. Because of the very large pressure created when the left ventricle contracts, the mitral valve wears out in many dogs. This wearing out process begins with a small leak that gradually gets more severe.
As animals age, the heart valves age as well, which can result in inefficiency and incomplete closure. Turbulence of the blood flowing through the faulty valve results in noise which is heard as a murmur. Sometimes there is a genetic predisposition for premature aging of the valve which would result in murmurs at a younger than anticipated age. Left untreated, dysfunction of the heart valves can lead to cardiomyopathy and heart failure. If murmurs are found on auscultation (part of every veterinary exam) then further diagnostics can be done (echocardiogram) to further diagnose the specific cause of the murmur so that treatment can be instituted to prevent, or delay, further deterioration of the heart.
We have not noted a significant incidence of premature valvular degeneration in the Havana Silk Dog but do recommend annual cardiac exams for all Silk Dogs and ask that anyone with a Silk Dog with early murmurs report them to the Health Committee.
Note: While OFA does maintain a Cardiac database it is specifically focused on 'congenital' cardiac defects therefore, OFA cardiac certification is no guarantee that a dog will not later develop cardiac abnormalities and does not replace annual cardiac examinations, which can be done by your veterinarian. If abnormalities are found, referral to a cardiologist can be requested. Septal defects (hole in the internal heart wall) is one congenital cardiac defect that can be detected by ausculation on puppies which is appropriate for listing in the OFA Congenital Cardiac database. See Health Testing ABCs for more information on congenital cardiac defects.
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| An HSD puppy bravely being BAER tested. |
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| Deafness
At this time deafness does not appear to be an issue in the Havana Silk Dog. HSDAA does require BAER testing to preclude the possibility of any deaf dog contributing to the gene pool. HSDAA breeders generally BAER test puppies before they go to new homes. We continue to screen because of the history of a low incidence of deafness in the Havanese gene pool....better to be safe than sorry.
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