NCS - Nutritional Diseases

Avian Nutritional Diseases

by Valerie L. Campbell, DVM

Nutrition in domestic animals traditionally treated by veterinarians has been researched extensively, and as a result many excellent commercial diets are readily available. The same is not true for caged birds. Little basic research has been done for birds, and there is not likely to be much more in the future.

Problems related to improper nutrition are extremely common in pet birds. In the larger parrot species (amazons, cockatoos, macaws), whose normal life spans are quite long, it is reported that the majority of these birds die within 5 years of purchase. Nutrition plays a major role in their demise.

A recent Dutch study revealed that 60% of the birds presented for autopsy showed signs of nutritional deficiency. In the field of avian medicine we suffer from a glut number of "old wives tales" regarding bird care. These include: "if your bird eats table food it will die" (the opposite is true); and "vitamins are not necessary because everything is in the seed." Traditional parrot diets have been "parrot mix," a mineral block, grit and water. The typical mix is sunflower seed, peanuts, safflower seed with some smaller seeds on occasion. Other foods often fed include apples, grapes, and lettuce, which provide very little nutritional value. As a primary diet, this fare is deficient in Vitamins A and D-3, calcium, zinc, and many essential amino acids while providing excess fat. Also, this diet in no way resembles the bird' natural diet. Vitamin A promotes proper skin and mucus membrane health. Lack of this nutrient leads to mouth abscesses and a decreased resistance to infections (particularly upper respiratory and sinus infections). This deficiency is one of the most commonly recognized in pet birds. Wild-caught birds take 2-3 years on an all seed diet before becoming deficient and ill. Foods high in Vitamin A include: winter squash, yams, sweet potatoes, carrots, parsnips, broccoli, brussel sprouts, cauliflower, cabbages, and turnips. CTreens high in Vitamin A include: carrot tops, turnip greens, dandelion greens and mustard greens. Chard and spinach are nutritious, but contain calcium-binding agents. Vitamin D-3 and calcium deficiency causes metabolic disease and hyperarathyroidism. In young birds, a diet deficient in these nutrients results in rickets. In older birds, deficiency results in an increased tendency towards long bone fractures, brittle beaks and feathers, and egg-laying problems. Vitamin D-3 is absent in most canine-feline pet foods (Vitamin D-2 is used). Cod liver oil is an excellent source, but tends to be messy. Foods high in calcium include: almonds, fortified breads, cereals and dairy products. Uncultured dairy products are not recommended (milk and ice cream) but cheese and yogurt are okay. This is because birds lack the enzyme to digest lactose, leading to osmotic diarrhea, crop stasis, and other digestive disturbances. Other sources of calcium include oyster shell, bone meal, commercial chews and avian supplements. Oyster shell and bone meal can be contaminated by heavy metals thus they are not recommended.

Unsupplemented seed diets do not provide the balanced protein needs of caged birds. The most common deficiencies are in lysine and methionine. The most obvious signs are poor feathering and lack of molt. Reduced reproduction and poor resistance to disease is common. Sources of quality protein include: hard-boiled eggs, poultry products, cultured dairy products, fish and beans. Pelleted diets are also rich in essential amino acids. One of the major problems in feeding a primarily seed diet is excess fat. Cage birds don't normally have large fat reserves, and seed diets tend to lead to obesity. Lack of quality protein and probably genetic factors predispose cage birds to fatty liver syndrome, lipomas, atheroscelerosis and xanthomas. Reducing fat calories by feeding more cereal grains (corn, wheat, rice, barley) seem to help prevent this.

Bacterial or fungal rontanization of seed mixes can also be a problem. Other microbial problems can come from food and water dishes that are not cleaned thoroughtly or routinely with effective disinfectants such as Clorox.