Failure to Absorb Vitamin B12 in Dogs

By PetMD Editorial on Oct. 10, 2008

Cobalamin Malabsorption

Cobalamin malabsorption refers to a genetic abnormality by which the vitamin B12, also known as cobalamin, fails to be absorbed from the intestine. This condition occurs secondary to the absence of a specific binding receptor in the lower intestine (the ileum) for intrinsic factor-cobalamin complex (IF-cbl). This is a rare disease that tends to affect Giant Schnauzers, Border Collies, and Beagles. In the Giant Schnauzer, it is inherited as a simple autosomal recessive trait. Symptoms generally appear at 6 to 12 weeks of age in Giant Schnauzers, and around four to six months in Border Collies.

Symptoms and Types

  • Anorexia
  • Lethargy
  • Failure to gain weight


The cause of this disease is genetic inheritance.


Your veterinarian will perform a thorough physical exam on your pet, with a complete blood profile, including a chemical blood profile, a complete blood count, and a urinalysis. The blood serum will be examined for cobalamin concentration levels; low levels would be indicative of an absorption failure. The serum check will also give some information on any secondary conditions affecting the body by how high the levels of white blood cells are in the blood serum. Urinalysis may return higher than normal levels of white blood cells as well. You will need to provide a thorough history of your pet's health leading up to the onset of symptoms, including any genetic information you have.

Your veterinarian may find chronic non-regenerative anemia, where the body does not respond to a deficiency of red blood cells, or mild to severe neutropenia, where the body is suffering from an abnormally low amount of white blood cell neutrophils.

Further tests may show that the failure of cobalamin to absorb is related to other congenital metabolic diseases, or to a parasite in the gastrointestinal tract.


Medical treatment can typically be on an outpatient basis, with long-term supplementary administration of cobalamin. Any other appropriate medications will be as prescribed by your veterinarian, based on the medical findings.

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