Dog Owner's Home Veterinary Handbook.pdf - Mr. Walnuts

THE CIRCULATORY SYSTEM • 353
history of bleeding from the gums following tooth eruptions, and oozing from
wounds following tail docking and dewclaw removal.
Breeds at risk for vWD in which bleeding is likely to be mild include the
Doberman Pinscher, Golden Retriever, Standard Poodle, Pembroke Welsh
Corgi, Manchester Terrier, Miniature Schnauzer, Akita, and others. Breeds in
which bleeding is likely to be more severe include the Scottish Terrier, Shetland
Sheepdog, German Shorthaired Pointer, and Chesapeake Bay Retriever.
Hypothyroidism is common in dogs with vWD, and may contribute to the
bleeding risk.
The diagnosis is made by specific blood tests, including a bleeding time. In
this test, a small cut is made and the amount of time it takes for bleeding to
stop on its own is measured. From a nail cut too short, two to six minutes is
normal, while from a cut on the gums, two to four minutes is normal. A quantitative
test for von Willebrand’s disease involves measuring the vWD antigen.
Dogs with vWD antigen levels below the normal range are at risk for
expressing and/or carrying the trait.
OFA maintains a vWD registry for many of the breeds mentioned here. A
DNA test to identify affected dogs and carriers is available through VetGen
and is the most accurate diagnostic test.
Hemophilia
This is a sex-linked recessive trait that occurs only in males who inherit a
maternal X chromosome carrying a defective gene. Females always inherit
two X chromosomes, at least one of which usually contains a normal dominant
gene. Thus females can carry the trait but do not develop the disease—
the exception being a female who inherits two recessive genes: one from a
hemophiliac father and the other from a mother who is either a hemophiliac
or a carrier. This is extremely rare.
Hemophilia produces bleeding into the chest and abdominal cavities, muscles,
and subcutaneous tissues. Bleeding into the joints is common.
Hemophilia A (the most common type) is a deficiency of coagulation factor
VIII. Hemophilia B is a deficiency of factor IX. Hemophilia occurs in all
breeds, with a predisposition among German Shepherd Dogs, Airedale
Terriers, and Bichons Frises.
Other coagulation deficiencies involve factors VII, X, XI, and prothrombin.
These deficiencies are inherited as single-factor autosomal traits and
affect males and females alike. They are less common than hemophilia.
Affected breeds include the Boxer, English and American Cocker Spaniel,
English Springer Spaniel, Beagle, and Kerry Blue Terrier.
The diagnosis of a coagulation factor deficiency is based on a number of
clotting tests, plus an analysis for the specific factor that is deficient.
PennGen offers genetic tests for factor VII and factor XI.