Overview of Zinc Deficiency in Dogs
Zinc deficiency in dogs can cause hair loss and skin problems. Zinc is an essential mineral required for the production of over 300 enzymes necessary for various bodily functions including healthy skin and hair, normal immune function, normal thyroid function, wound healing, and normal sexual function.
Zinc should be a normal component of a dog's diet. The absence of zinc in the diet can cause various abnormalities affecting the skin, metabolic function and immune function. Zinc deficiency causes the condition called zinc responsive dermatosis.
Zinc isn't readily or easily absorbed by intestine of dogs. It is estimated that only 5 to 40% of ingested zinc is absorbed in normal dogs.
Causes of Zinc Deficiency in Dogs
Causes and risk factors for canine zinc deficiency include:
- Young puppies and dogs fed a diet deficient in zinc.
- Diets rich in calcium prevent normal zinc absorption. Calcium binds with zinc, which prevents absorption.
- Dog breeds such as the Siberian Husky or Alaskan Malamute have a genetic inability to absorb zinc properly. Zinc deficiency has also been reported in Bull Terriers, Labrador Retrievers,
- Doberman Pinschers, Standard Poodles, German Shepherd dogs, Golden Retrievers, Rottweilers, German Shorthaired Pointers, Beagles, Rhodesian Ridgebacks and Great Danes.
- Diets excessively high in zinc prevent normal zinc absorption.
- Diets with low levels of total fat and essential fatty acids affect zinc absorption
- Plants contain a substance called phytate which hampers the absorption of zinc. Diets that are high in fiber (plant-based) can cause zinc deficiency.
- Inflammatory bowel disease can cause abnormal absorption of zinc.
What to Watch For
Signs of zinc deficiency in dogs may include:
- Hair loss (Alopecia)
- Scaling and crusting skin lesions around the face, head, legs, and pads of the feet
- Red or swollen footpads
- Thickened crusted footpads
- Fissures (cracks) on the nose and/or footpads
Severely affected dogs may display:
- Generalized lymph node enlargement
- Lack of appetite (anorexia)
- Stunted growth in puppies
- Increased incidence of infection such as pneumonia or infections around the eyes and mouth
Diagnosis of Zinc Deficiency in Dogs
Diagnosis of zinc deficiency is often made based on the clinical signs and history. Other diagnostic possibilities may include:
- Zinc levels can be measured but are often unreliable based on various laboratory procedures. Zinc blood levels less than 0.8 ppm is suggestive of zinc deficiency although Zinc blood levels can be affected by age and other illnesses making them difficult to interpret.
- A skin biopsy submitted for histopathology may reveal classing signs of zinc deficiency including skin changes suggestive of zinc deficiency but is not considered diagnostic.
- Response to therapy with zinc supplementation is one informal way zinc deficiency is sometimes confirmed.
Treatment of Zinc Deficiency in Dogs
- Treatment is focused on daily zinc supplementation. Normal growing puppies require approximately 60 mg to 150 mg of zinc per pound of body weight (120 mg to 300 mg of zinc per kilogram) depending on the activity level of the dog. Working dogs require higher levels of supplementation. Supplementation should include up to 500 mg/pound (1000 mg/kg) of zinc for zinc deficient dogs. Breeds at risk should be supplemented with zinc.
- Normal sources of zinc include meat and fish products. Grains are low in zinc such as corn and soybean. For example, a meal of rice has only 10 to 12 mg/lb of zinc while a meat meal contains 50 mg/lb and a fish meal contains approximately 75 mg/lb of zinc.
- Zinc is available in many forms including an injectable version that can be given intravenously (IV) and oral supplements. Forms may include zinc sulfate (oral and IV), zinc methionine (oral), and zinc gluconate (oral). Common dosage recommendations for dogs may include:
- Zinc sulfate oral: 5 mg/pound once daily (10 mg/kg)
- Zinc methionine oral: 0.8 mg/pound daily (2 mg/kg)
- Zinc gluconate: 0.75 mg/pound daily (1.7 mg/kg)
- Some veterinarians recommend crushing tablets and mixing with food to encourage dogs to eat it well and minimize stomach upset which can occur with zinc administration.
- Treats supplemented with zinc are also available such as dog treat by Zinpro (by Lincoln Biotech) which contains zinc methionine.
- In addition to zinc supplementation, some dogs with infections may require antibiotic.
- Therapeutic baths with shampoos to help remove crusts may be recommended. Examples of keratolytic shampoos include those with ingredients of sulfur and/or salicylic acid.
- Some cases that do not respond to initial supplementation and above treatments may also need oral steroid therapy which can help increase absorption of zinc.