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Anemia Due to Enlarged Blood Cells in Dogs

Anemia, Megaloblastic (Anemia, Nuclear Maturation Defects) in Dogs


In this disease, red blood cells fail to divide and become abnormally large. These cells are also deficient in necessary DNA material. These giant cells with underdeveloped nuclei are called megaloblasts, or “big cells.” Red blood cells are mainly affected, but white blood cells and platelets can also go through changes.

Giant schnauzers seem to have an inherited tendency to have this kind of anemia. In dogs, it is generally mild, and left treated. The seriousness of the anemia can range from mild to severe. This disease is genetic in Toy Poodles, but it does not require treatment.

The condition or disease described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats, please visit this page in the PetMD health library.

Symptoms and Types


  • Deficiencies of Vitamin B-12 and folic acid
  • Leukemia
  • Bone marrow disorder
  • Genetics
  • Drugs such as chemotherapy


Tests will be conducted to rule out the following:

  • All mild to moderate non-regenerative anemias, including those of inflammatory disease, renal disease, and lead poisoning
  • Complete blood counts will be taken and bone marrow aspiration analysis

Complete blood count, biochemistry, and urinalysis will examine the following:

  • Is the anemia mild or moderate?
  • Is the anemia caused by over-sized cells?
  • Bone marrow biopsy usually reveals if there are an abnormal amount of cells



An in-depth examination of the properties of urine; used to determine the presence or absence of illness


The prediction of a disease’s outcome in advance


The process of removing tissue to examine it, usually for medical reasons.


A condition of the blood in which normal red blood cell counts or hemoglobin are lacking.