Understanding vWD in Dogs
Von Willebrand Disease (vWD) is a hereditary bleeding disorder that affects dogs. It is caused by a deficiency or reduced level of von Willebrand factor (vWF), which is a clotting protein in the blood. This protein plays a crucial role in the adhesion of platelets to damaged blood vessels, facilitating the formation of blood clots. When dogs lack sufficient vWF, their blood may not clot properly, leading to potential bleeding and prolonged bleeding times.
What is Von Willebrand Disease?
Von Willebrand Disease (vWD) is an inherited bleeding disorder in dogs, characterized by a deficiency or reduced level of the von Willebrand factor (vWF) clotting protein. vWF is essential for the formation of blood clots, as it promotes platelet adhesion and stabilizes blood clots. Dogs with vWD may experience symptoms ranging from mild to severe bleeding, especially after injuries, surgeries, or giving birth.
The age of onset for vWD can vary among dogs. Some may show signs of the disease early in life, while others may only exhibit symptoms later in life. It is important to note that vWD is a lifelong condition and requires ongoing management.
Symptoms and Severity
The severity of vWD symptoms can vary depending on the individual dog and the type of vWD they have. Some dogs may show no apparent signs of the disease and live a normal life without experiencing significant bleeding episodes. However, in more severe cases, uncontrolled bleeding can occur, leading to potentially life-threatening situations without medical intervention.
Common symptoms of vWD in dogs include:
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- Skin bruising
- Bleeding from the gums or nose
- Excessive bleeding during surgeries or after injuries
- Prolonged bleeding after giving birth
It’s important to recognize these symptoms and seek veterinary care if you suspect your dog may have vWD. While there is no cure for vWD, proper care and management can help dogs with the condition live a normal lifespan. Your veterinarian can provide guidance on monitoring your dog’s condition and recommend appropriate measures to prevent excessive bleeding episodes (Cornell University College of Veterinary Medicine).
In the next section, we will explore the different types of vWD that can affect dogs, including vWD Type 1, vWD Type 2, and vWD Type 3.
Types of vWD in Dogs
Von Willebrand Disease (vWD) in dogs is classified into three types: Type 1, Type 2, and Type 3. Each type has distinct characteristics and varying levels of severity.
vWD Type 1
vWD Type 1 is the most common form of the disease in dogs. It is characterized by low levels of von Willebrand Factor (vWF) in the blood. vWF plays a crucial role in blood clotting, and its deficiency can lead to a bleeding disorder.
Type 1 vWD is generally less severe than Type 2 and Type 3 vWD and can often be managed with appropriate treatment. It is associated with a specific mutation (c.7437G>A) in the vWF gene and is inherited as a dominant trait with incomplete penetrance.
vWD Type 2
vWD Type 2 is less common than Type 1 and is characterized by qualitative defects in vWF. Dogs with Type 2 vWD may have reduced levels of vWF or abnormal forms of the protein that are less effective in promoting clotting. This type of vWD can be more severe than Type 1 and may require more intensive management and treatment (UC Davis Veterinary Genetics Laboratory).
Within Type 2 vWD, there are further classifications based on the specific defect in the vWF protein. These include Type 2A, Type 2B, Type 2M, and Type 2N. Each subtype has its own distinct characteristics and may require tailored treatment approaches.
vWD Type 3
vWD Type 3 is the most severe form of the disease. Dogs with Type 3 vWD have extremely low or undetectable levels of vWF. This complete absence of vWF significantly impairs blood clotting, leading to excessive and potentially life-threatening bleeding (UC Davis Veterinary Genetics Laboratory).
Type 3 vWD is inherited as an autosomal recessive trait, meaning that both parents must carry the defective gene for a dog to be affected. Breeding between two carriers of Type 3 vWD is strongly discouraged to prevent the transmission of this serious bleeding disorder to offspring (Veterinary Partner).
Genetic testing for vWD Type 1, Type 2, and Type 3 is available at the Veterinary Genetics Laboratory (VGL). This testing can help breeders assess the genetic status of breeding dogs and identify the risk for bleeding disorders. The VGL offers a single test for vWD Type 1 at a cost of $55 per animal, with a $5 discount for testing three or more dogs. The results of the test can also be submitted to the Orthopedic Foundation for Animals (OFA) (UC Davis Veterinary Genetics Laboratory).
Understanding the specific type of vWD in a dog is essential for appropriate management and treatment. Genetic testing can provide valuable information for breeders and veterinarians, allowing them to make informed decisions about breeding programs and tailor care plans for affected dogs.
Breeds at Risk
Von Willebrand Disease (vWD) can affect various dog breeds, but some breeds have a higher prevalence of the disease. Here are three breeds that are particularly at risk:
Doberman Pinscher
The Doberman Pinscher is the breed with the highest incidence of von Willebrand Disease (vWD). According to VCA Hospitals, over 70% of 15,000 Dobermans screened were found to be carriers of the disease. However, it’s important to note that many of these carriers did not show signs of the disease at the time of testing. On average, diagnosis typically occurs around four years of age. To learn more about vWD in Doberman Pinschers, visit our article on von Willebrand Disease in Dogs.
Scottish Terrier
Scottish Terriers have also been found to be at risk for von Willebrand Disease. About 30% of Scottish Terriers were found to have abnormally low concentrations of von Willebrand factor, a key protein involved in blood clotting. This breed is particularly susceptible to the more severe forms of the disease. Regular testing and monitoring are crucial for Scottish Terriers to ensure their well-being.
Shetland Sheepdog
Shetland Sheepdogs, also known as Shelties, are another breed that can be affected by von Willebrand Disease. Similar to Scottish Terriers, approximately 28% of Shetland Sheepdogs have been found to have abnormally low concentrations of von Willebrand factor. While not as prevalent as in Doberman Pinschers, it is still important for Sheltie owners to be aware of this potential health concern and consider testing and preventive measures.
Regular screening and testing for von Willebrand Disease are essential for these at-risk breeds. Additionally, other breeds, such as Golden Retrievers, Rottweilers, and German Shepherds, are also routinely tested for vWD. By being proactive in monitoring and managing vWD in these susceptible breeds, dog owners can help ensure the well-being and health of their furry companions.
Diagnosis and Testing
When it comes to identifying and confirming von Willebrand Disease (vWD) in dogs, proper diagnosis and testing are essential. Two primary methods used for diagnosing vWD in dogs are buccal mucosal screening and von Willebrand factor testing.
Buccal Mucosal Screening
A screening test called buccal mucosal screening time can be performed in the veterinarian’s office to raise suspicion of von Willebrand’s disease, especially in breeds known to be at risk. This test involves collecting a sample of cells from the dog’s cheeks and gums using a cytology brush. The sample is then assessed to determine the time it takes for bleeding to stop and clot formation to occur. Abnormal results from this screening test can indicate the presence of vWD.
Von Willebrand Factor Testing
To confirm the diagnosis of vWD and determine the exact amount of von Willebrand factor (vWF) present in the blood, a laboratory blood test is necessary. The primary test used is the von Willebrand factor antigen assay (VWF:Ag), which measures the concentration of vWF in a blood sample. This test is crucial for accurately diagnosing vWD in dogs.
Dogs with low plasma VWF:Ag levels below 50% are predicted to be at risk of transmitting or expressing the vWD trait. Severely affected dogs typically have marked reduction in plasma VWF:Ag, with values of less than 25%. It is important to note that proper sample collection, processing, and shipping methods are critical to ensure accurate results. Inaccurate results can occur due to clots or hemolysis in the sample, which is why following the recommended procedures is essential.
For certain breeds at risk of vWD, DNA testing is available to determine if a dog is clear, affected, or a carrier of the disease. This type of genetic testing is typically used in breeding programs to make informed decisions about potential breeding pairs. It involves collecting a DNA sample by brushing cells from the dog’s cheeks and gums, which can be done using cytology brushes provided by specialized laboratories. It is recommended to wait until puppies are at least three weeks old before performing the DNA test.
By utilizing buccal mucosal screening and von Willebrand factor testing, veterinarians can accurately diagnose vWD in dogs. These diagnostic tools help to determine the severity of the condition, guide treatment decisions, and assist in breeding programs to prevent the spread of vWD in susceptible breeds.
Treatment Options
When it comes to managing von Willebrand disease (vWD) in dogs, there are various treatment options available to help control bleeding episodes and improve the overall quality of life for affected dogs. These treatment options include medications and therapies, as well as emergency interventions.
Medications and Therapies
One common treatment option for vWD in dogs is the administration of medications and therapies. One such medication is desmopressin acetate, which is a synthetic hormone that helps increase the amount of von Willebrand factor (vWF) in the blood. Desmopressin acetate can be administered intravenously or as a nasal spray, and it works by temporarily boosting the levels of vWF, thereby improving the blood clotting process and reducing the risk of bleeding (Cornell University College of Veterinary Medicine).
In certain cases, blood products such as cryoprecipitate or fresh frozen plasma may be used to control bleeding episodes in dogs with vWD. These products contain clotting factors, including vWF, that can help promote blood clot formation and prevent excessive bleeding. Transfusion of blood or fresh frozen plasma from a healthy donor dog may be necessary in emergency situations to stabilize a bleeding dog with vWD. Prior to blood collection, the donor dog may receive a drug called DDAVP to increase the level of vWF in the blood, which can benefit the dog with vWD (VCA Canada, VCA Hospitals).
Emergency Interventions
In emergency situations where a dog with vWD experiences severe bleeding or trauma, immediate intervention is crucial. Transfusion of blood or fresh frozen plasma may be necessary to stabilize the dog and replace the clotting factors that are deficient in vWD. DDAVP may also be used to raise the level of vWF in the blood of the donor dog, benefiting the dog with vWD during emergency transfusions (VCA Canada, VCA Hospitals).
It’s important to note that certain medications can decrease platelet function and increase the risk of spontaneous bleeding in dogs with vWD. Additionally, emotional stress may precipitate bleeding in some cases. Therefore, it’s crucial for dog owners to closely monitor their pets for any signs of bruising or bleeding, especially during stressful events. Maintaining a stress-free lifestyle for dogs diagnosed with vWD can help minimize the risk of bleeding episodes.
By utilizing various medications, therapies, and emergency interventions, veterinary professionals can provide effective treatment and management strategies for dogs with vWD. Regular monitoring, close communication with the veterinarian, and adherence to the recommended treatment plan are essential for ensuring the well-being of dogs affected by this inherited bleeding disorder.
Breeding Considerations
When it comes to breeding dogs, it is important to consider the hereditary transmission of von Willebrand disease (vWD). Understanding the hereditary nature of this condition and following appropriate breeding guidelines can help reduce the prevalence of vWD within a particular breed or line of dogs.
Hereditary Transmission
vWD in dogs is an autosomal trait, meaning that both males and females can transmit and express the condition with equal frequency. Dogs with one abnormal von Willebrand factor (VWF) gene may exhibit abnormal and variable bleeding, a pattern known as “incomplete dominance” (Cornell University College of Veterinary Medicine).
In the case of vWD types 2 and 3, the condition typically shows a recessive expression pattern. This means that clinically affected dogs have inherited two abnormal VWF genes, one from each parent. Breeds with type 1 vWD may exhibit a different inheritance pattern, with one abnormal VWF gene resulting in a milder form of the disease.
Breeding Guidelines
To minimize the risk of vWD in future generations, breeding guidelines based on VWF:Ag (von Willebrand factor antigen) diagnostic ranges or genetic tests can be followed. Dogs that test within the normal range (VWF:Ag > 70%) are recommended for breeding programs, as they are more likely to produce vWD-clear offspring.
Dogs that fall within the borderline or abnormal range may still be considered for breeding if they do not exhibit a bleeding tendency. However, it is ideal to breed these individuals with test-clear mates to reduce the proportion of vWD carriers in subsequent generations. By following these guidelines, breeders can make informed decisions to help reduce the prevalence of vWD while maintaining the health and well-being of their breeding lines.
When considering breeding dogs, particularly those susceptible to vWD, it is crucial to prioritize the health and welfare of the offspring. Consultation with a veterinarian or genetic counselor experienced in canine von Willebrand disease can provide valuable guidance and support in making responsible breeding decisions.
