Anemia

• Of all the canine blood disorders, anemia is the most commonly diagnosed, and happens when the blood, the blood cells in particular, are not circulating properly. There are two types of anemia. The first is regenerative anemia and typically happens after an injury, and the dog will often recover on his own or after blood transfusions. The second time is non-regenerative anemia and is diagnosed when the blood cells have defects that are permanent. This type of anemia may be the result of genes or from problems, such as cancer.
  
  

Coagulation and Platelet Disorders

• These disorders relate to the blood not clotting properly. To protect your dog's body from excessive bleeding or internal injury, the blood must clot at a specific rate. In these disorders, the blood does not clot, or at least not fast enough, and the dog may have internal bleeding. If there's a cut, you may not be able to stop the bleeding. Most dogs with a coagulation or platelet disorder are born with it, though they often die shortly after birth.
  
  

Vascular Disorders

• The most common vascular disorder is Rocky Mountain spotted fever, a disease which is spread by ticks. According to "The Dog Health Handbook," vascular disorders in dogs occur when there "are deficiencies of collagen protein in the blood."
  
  

Infection Related Blood Disorders

• These types of blood disorders generally occur in response to an infection somewhere in your dog's body. Leukopenia results when there is a reduced white blood cell count, and Leukocytosis is an increase in white blood cells.
  
  

Cancer

• There are certain types of cancer that will cause changes in your dog's blood. For example, bone marrow cancers will alter counts in both red and white blood cells. In certain types of tumors, such as hemangiosarcoma tumors, blood disorders will also appear, such as problems with the blood thinning and not clotting properly.