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Folate Levels and Recommendations for Supplementation

Experimentally induced folate deficiency can lead to anemia (with a tendency for it to be macrocytic), leukopenia, weight loss, erratic appetite, decreased weight gain, watery exudate from eyes, glossitis, decreased antibody response to viral infection, and an increased rate of birth defects in dogs and weight loss, anemia (with a tendency for it to be macrocytic) and leukopenia in cats.

To our knowledge the benefit of supplementing folic acid to dogs and cats with gastrointestinal disease and serum folate concentrations below the lower limit of the reference interval has not been clearly demonstrated. However, because experimentally-induced folate deficiency can lead to clinical consequences and folic acid is cheap and safe we consider supplementation in animals with a decreased serum concentrations. The difficulty in administering pills to the patient and the severity of their hypofolatemia also influence our decision whether to treat individual patients or not.

Folic acid supplements sold for use in humans are readily available. We recommend a dose of 200 mcg for cats and smaller dogs (<20 kg BW) and 400 mcg for larger dogs (20 kg BW) PO once daily for 4 weeks. It is very important to also address the proximal small intestinal disease that is suspected as the underlying cause of the decreased serum folate concentration. If the animal’s clinical signs have resolved, we do not usually recheck serum folate concentrations. If the clinical signs are persistent, rechecking serum folate concentration 1 week after supplementation is stopped may be helpful