Veterinary Guide to Cobalamin (Vitamin B12) Malabsorption in Dogs (2025)🐶 

By Dr. Duncan Houston BVSc

🔍 Introduction

Cobalamin malabsorption (B₁₂ deficiency) in dogs may be inherited (e.g., Imerslund–Gräsbeck syndrome) or acquired due to GI disease. This condition impairs red blood cell production, energy, and gut health. Early detection, proper testing, and B₁₂ supplementation are critical for recovery. 🐾

💡 Inherited vs. Acquired Causes

• Genetic (Imerslund–Gräsbeck syndrome): caused by missing ileal receptors (Cubilin/Amnionless), affecting breeds like Giant Schnauzers, Beagles, Border Collies.
• Acquired deficiency: associated with exocrine pancreatic insufficiency (EPI), chronic enteropathy, or SIBO disrupting intrinsic factor or ileal absorption.

⚠️ Clinical Signs

• Poor growth, anorexia, lethargy, weight loss despite appetite.
• GI signs: chronic diarrhea, vomiting, gas—common in malabsorption.
• Blood abnormalities: nonregenerative anemia, neutropenia; rare neurologic signs or seizures in severe cases.

🔬 Diagnostic Approach

• Measure serum cobalamin; low levels suggest deficiency—but normal levels don’t rule out intracellular deficiency. Consider methylmalonic acid (MMA) or homocysteine testing for confirmation.
• Assess GI health: CBC, chemistry, TLI for EPI, folate levels, imaging, fecal parasitology.
• Genetic testing for suspected inherited cases in relevant breeds.

🛠 Treatment & Supplementation

• Parenteral B₁₂ supplementation (SC injections): weekly for 6–8 weeks, then monthly lifelong for inherited cases.
• Oral supplementation: may be effective if GI absorption intact; less reliable if malabsorption is severe.
• Treat underlying GI disease: pancreatic enzymes for EPI, dietary trials or antibiotics for chronic enteropathy/SIBO.

📈 Prognosis & Follow-Up

• Cobalamin repletion often rapidly improves appetite, energy, GI health.
• Monitor serum B₁₂ levels and adjust supplementation schedule as needed.
• Ongoing management required for inherited forms—lifelong injections and regular check-ups.

🛡 Prevention & Breeding Advice

• Breed counseling: avoid breeding dogs with genetic B₁₂ malabsorption.
• Early GI screening in at-risk breeds to catch malabsorption or EPI promptly.
• Maintain balanced diets and manage GI disorders proactively.

🔧 Tools & Support Services

• Ask A Vet App: 24/7 support for interpreting labs, guidance on injections, and treatment plans 📱

✅ Final Thoughts

Cobalamin malabsorption in dogs—even if rare—can profoundly affect growth, GI function, blood health, and neurologic status. With accurate diagnosis, appropriate B₁₂ supplementation, and management of underlying causes, many dogs recover well. Genetic cases require lifelong treatment and breeding consideration. In 2025 and beyond, tools like Ask AVet, effective care. 🐾❤️

Download the Ask A Vet app today for expert B₁₂ treatment plans, long-term tracking, and personalized support. 📱💡