What Is Von Willebrand Disease?
Von Willebrand disease (vWD) is the most common inherited bleeding disorder in dogs. It is caused by a deficiency or functional abnormality of von Willebrand factor (vWF), a large glycoprotein that plays a critical role in the early stages of blood clot formation. When a blood vessel is damaged, vWF acts as a bridge between the vessel wall and platelets, allowing platelets to stick together and form the initial platelet plug that stops bleeding. Without sufficient functional vWF, this plug forms poorly or not at all, resulting in prolonged or excessive bleeding from wounds, surgical incisions, and mucosal surfaces.
The condition was first described in humans by Finnish physician Erik von Willebrand in 1926, and the canine equivalent has since been recognised in over 50 breeds. It follows an autosomal pattern of inheritance — meaning it is carried on non-sex chromosomes — though the specific mode (dominant, recessive, or incomplete penetrance) varies between breeds and disease types.
The Three Types of Von Willebrand Disease
Type 1: Mild Deficiency
Type 1 vWD is the most common form. Dogs with Type 1 have a partial reduction in vWF levels but the protein that is present is structurally normal and functional. Bleeding tendency is mild to moderate, and many affected dogs go through life without any obvious clinical problems unless they undergo surgery, trauma, or a procedure that challenges their haemostatic system. The Dobermann Pinscher is the most significantly affected breed for Type 1 vWD, with studies suggesting that approximately 70 percent of Dobermanns in some populations carry the gene mutation. Other breeds with Type 1 include the German Shepherd, Golden Retriever, and Pembroke Welsh Corgi.
Type 2: Moderate Deficiency
Type 2 vWD is less common but more severe than Type 1. In this form, not only is the total amount of vWF reduced, but the largest and most functional forms of the protein — known as high-molecular-weight multimers — are absent or markedly reduced. The German Shorthaired Pointer is the breed most associated with Type 2 vWD, and affected dogs typically experience more significant bleeding episodes than those with Type 1. Type 2 is considered a moderate bleeding disorder.
Type 3: Severe Deficiency
Type 3 vWD is the most severe form and is fortunately the rarest. Affected dogs have a complete or near-complete absence of vWF, resulting in severe, spontaneous bleeding that can occur without any obvious precipitating cause. Bleeding into joints, muscles, and body cavities can occur alongside the more typical mucosal and wound bleeding seen in Types 1 and 2. Breeds most commonly affected by Type 3 include the Chesapeake Bay Retriever, Scottish Terrier, Shetland Sheepdog, and Kooikerhondje. Surgical procedures in Type 3 affected dogs carry extremely high haemorrhagic risk and require specialist planning.
Recognising the Signs
The most common clinical signs of von Willebrand disease reflect a primary haemostatic defect — that is, a problem with the initial platelet plug, rather than with the clotting cascade. This means bleeding tends to be from mucosal surfaces and minor wounds, rather than the deep-tissue or spontaneous bleeding into joints more typical of haemophilia.
- Prolonged bleeding from minor cuts, nail clips, or skin wounds
- Excessive bleeding during or after surgery or dental procedures
- Spontaneous nosebleeds (epistaxis)
- Blood in the urine or stools
- Bleeding from the gums
- Prolonged bleeding during oestrus in females
- Unexpected bleeding from the umbilicus in neonatal puppies
Many dogs with Type 1 vWD have no clinical signs at all and are only identified through screening prior to surgery or through routine DNA testing.
Diagnosis
Buccal Mucosal Bleeding Time
The buccal mucosal bleeding time (BMBT) test is a simple in-clinic screening tool. A standardised, spring-loaded device is used to make a small, consistent incision in the mucous membrane of the upper lip, and the time taken for bleeding to stop is recorded. A prolonged BMBT (typically more than four minutes in dogs) suggests a primary haemostatic defect and is consistent with vWD, though it is not diagnostic on its own as other platelet disorders can give the same result.
vWF Antigen Testing
A quantitative measurement of vWF antigen in the blood confirms the deficiency. Samples are typically sent to a specialist laboratory, and results are expressed as a percentage of normal. In general, dogs with vWF levels above 70 percent are considered normal, 50 to 70 percent is borderline, and below 50 percent is diagnostic for vWD. Very low levels — below 15 to 20 percent — are associated with a significant bleeding risk.
DNA Testing
Genetic testing is now available for vWD in many of the commonly affected breeds and is strongly recommended for breeding decisions. A DNA test can identify dogs as clear (two normal copies of the gene), carriers (one normal copy and one mutated copy), or affected (two mutated copies). Carriers typically do not bleed excessively themselves but can pass the mutation to offspring. DNA testing is reliable, non-invasive (a cheek swab is usually sufficient), and permanent — unlike vWF antigen levels, which can fluctuate with illness, stress, and hormonal status and may give misleading results in some circumstances.
Treatment and Pre-Surgical Management
Desmopressin (DDAVP)
Desmopressin acetate (DDAVP) is a synthetic analogue of the hormone vasopressin. In dogs with Type 1 vWD, administration of DDAVP before surgery stimulates the release of stored vWF from the endothelial cells lining blood vessels, temporarily increasing circulating vWF levels and improving haemostasis. It is given as a nasal spray applied to the conjunctiva or as an intravenous injection, typically 30 to 60 minutes before a procedure. The effect lasts for approximately one to two hours and is most reliable in Type 1 vWD. DDAVP is less effective in Types 2 and 3, where structural protein abnormalities or complete absence of vWF mean that releasing more stored protein does not significantly help.
Blood Products
For dogs undergoing major surgery or those experiencing significant haemorrhage, fresh frozen plasma or cryoprecipitate — a plasma fraction rich in vWF and clotting factors — can be administered to provide the missing protein directly. These options are particularly important for Type 3 affected dogs in whom other strategies are insufficient.
Responsible Breeding
Because vWD is an inherited condition, responsible breeding is the most effective tool for reducing its prevalence. Breeders should DNA test all dogs before breeding and avoid mating two carriers or affected dogs together. Eliminating all carriers from breeding programmes too rapidly can reduce genetic diversity in some breeds, so gradual selection pressure — pairing a carrier with a clear dog and selecting clear offspring for the next generation — is a balanced approach. Breed clubs for at-risk breeds often publish health testing protocols that include vWD screening as a standard requirement.