Vitamin B12 (Cobalamin)

Vitamin B12 (cobalamin) is an important nutrient for animal health because of its role in metabolizing nucleic acids (e.g., DNA) and forming proteins from amino acids. It also helps the body process fats and carbohydrates, and is used by the liver to make glucose.

Cobalamin interacts with folic acid in several interesting ways:

Vitamin B12 modifies folic acid so that the cells can use it.
The two vitamins work together to produce certain essential amino acids.
Both vitamins play a role in manufacturing red blood cells.

Vitamin B12 is necessary for the growth and reproduction of many cells, which is especially critical for DNA repair and fetal development. Other useful functions include maintaining the nervous system and aiding sheep in the production of wool.

Natural Sources

Vitamin B12 is unique in that it can only be produced by microorganisms. For this reason, it is not common in plants (with the exception of seaweed), although it can be found to some degree in animal-based feeds, particularly organ meats and seafood. Young animals can obtain the vitamin from colostrum, but only in small quantities. Fortunately, vitamin B12 is extremely potent.

Microorganisms living inside of grazing animals can usually supply enough vitamin B12 to meet the animal’s needs as long as adequate cobalt is provided (cobalt is necessary for cobalamin synthesis). In natural production systems, swine and poultry obtain this vitamin by picking through their litter and reusing nutrients lost in their waste.

Causes of Deficiency

Cobalt

Stress is one possible cause of a cobalamin deficiency in all types of livestock. This means that illness, pregnancy, rapid growth, or severe parasite infestations can increase the risk of shortfall. Another major cause of vitamin B12 deficiency is cobalt deficiency, since the mineral is necessary to synthesize the vitamin.

In ruminants, anything which interferes with the microbial activity of the digestive system can cause a deficiency. This typically means high-concentrate, low-fiber rations. Even in the pasture, however, large amounts of legumes can create problems.

Cobalamin deficiencies in swine and poultry are becoming more common in industrial settings because the animals are confined without access to their own waste. Although this is understandable for sanitary reasons, they are actually being denied their primary source of the vitamin. This, combined with a plant-based diet, can spell disaster.

Pancreatic and intestinal diseases can lead to vitamin B12 deficiency in cats and dogs. Any disease which causes excessive water consumption, such as diabetes, may flush the vitamin out of the animal’s body. Also, cats and several dog breeds can inherit a condition which impairs their ability to absorb vitamin B12 from their food. Cobalamin deficiencies are rare in pets without underlying health problems, but a deficiency can be caused by feeding a vegetarian diet.

Symptoms of Deficiency

Signs of a vitamin B12 deficiency vary, and they tend to be extremely nonspecific. The general impression, however, is one of a wasting disease.

Impaired immune function.
Mild fatigue.
Confusion.
Increased excitability.
Subnormal body temperature.
Runny eyes.
Mild conjunctivitis.
Blindness in cats.
Scaly ears.
Swollen tongue.
Loss of voice in swine.
Rough skin and coat.
Reduced wool growth and quality.
Poor feathering.
Muscular weakness.
Unsteady gait.
Slipped tendons in chicks.
Mild anemia.
Poor appetite.
Weight loss.
Vomiting.
Diarrhea.
Reduction in egg size.
Reduced hatchability (mortality peaks at 17th day of incubation).
Abortions.
Reduced litter sizes in swine.
Birth defects.
Low birth weights.
Poor milk production.
Dramatically reduced growth.
High mortality rate.

Symptoms of Toxicity

Although some forms are available by prescription only in the United States, vitamin B12 is considered safe for most animals in good health. Toxicity is a possibility in animals with impaired renal function. Symptoms of overdose may include:

Itching.
Diarrhea.

Unfortunately, potentially hazardous additives are sometimes used in preparing supplements. Some oral forms use xylitol, which is toxic to dogs, as a sweetener. Injectable cobalamin often contains aluminum at levels that can be toxic over time, particularly in animals with impaired kidney function.

Medicinal Uses

Since the signs of cobalamin deficiency are so nondescript, some producers consider supplementation a good idea in any situation where an animal is “just not itself.” This can include assisting baby animals that have gotten off to a bad start for no obvious reason.

Vitamin B12 may be used successfully to treat some cases of anemia. It can also help repair the digestive system after a worm infestation or a round of antibiotics, and is helpful for short-term stabilizing of pets diagnosed with diabetes, pancreatic insufficiency, or kidney disease.

In otherwise healthy animals, vitamin B12 can be used as a preventative measure to counteract the effects of stress. For example, this vitamin is sometimes given to performance horses to help them fight fatigue and keep up a healthy appetite.

Content regarding medical conditions and treatment is provided for general information purposes only, and is not to be construed as legal, medical, or professional advice. Please consult your veterinarian for advice regarding your specific animal’s needs.