One dog suddenly starts turning up her nose at the wholesome food that her owners have been routinely feeding her for years. Another will gorge himself ravenously on any old food that's put in front of him. A third dog seems to have a taste for indigestible substances; you've seen him snacking, for example, on the gravel in your driveway.
Poor health, bizarre taste or just plain bad habits can be responsible for a wide variety of perplexing and sometimes very dangerous canine eating disorders. Some of these disorders may be attributable to an underlying and possibly life-threatening physical ailment. Others, while presenting a less severe health risk, are troublesome, often disgusting to witness and if allowed to continue may eventually be physically harmful. And still others, though merely annoying, may be symptomatic of flaws in a dog's overall training.
Issues of Concern
Two eating-related disorders, anorexia (food avoidance) and polydipsia (excessive water consumption), may signal the presence of serious disease. A third, polyphagia (excessive food consumption) is likely, if unaddressed, to lead to obesity and the many health problems associated with it.
Typically marked by a dramatic loss of appetite and the avoidance of all food, this eating disorder may be accompanied by high fever and, if untreated, alarming weight loss. The condition accompanies a wide range of ailments, including diseases associated with the respiratory system, nervous system, stomach, kidneys, pancreas, liver, blood or skin. Dogs have also been known to lose their appetites for emotional reasons, such as the introduction of a new animal into a household or relocation to a new home.
"If your dog doesn't eat for a day or two, I don't think you have anything to worry about," says Francis Kallfelz, DVM, a professor of veterinary nutrition at Cornell University's College of Veterinary Medicine. "But if the animal goes without eating for more than several days, you should have it checked out by a veterinarian."
A dog should normally consume about 32 milliliters (a little more than an ounce) of water daily for each pound of body weight. "This can vary, of course, depending on how much exercise the animal is getting and on the ambient temperature," Dr. Kallfelz points out. "It will consume more water if it is very active, and it will drink more on very hot days." Another factor is the type of food that it routinely eats. A dog that eats dry food will tend to drink more water than an animal that eats canned food, which is 80 percent water.
If you notice that your dog is constantly at its water bowl, desperately trying to slake an apparently unquenchable thirst, you are witnessing the classic signs of polydipsia, a disorder often associated with such life threatening ailments as diabetes and kidney failure. An animal demonstrating this behavior which is usually accompanied by excessive urination (polyuria) is also likely to be losing weight and to appear lethargic and depressed.
This eating behavior the habit of consuming as much food as possible as frequently as possible - may perhaps be an inclination inherited by the domestic dogs of today from their feral ancestors. In ages past, those ancestors would wisely eat more than they needed during the fleeting periods when food was abundant in order to tide them over when food became scarce.
Nowadays, this gluttonous habit may be perpetuated by dog owners through free-choice feeding (feeding the bowl rather than the dog). Unfortunately, this can put a dog at risk for obesity when the animal is 20 to 30 percent or more over its appropriate weight. The severe consequences of this condition include an elevated risk for diabetes, cardiac conditions, hypertension, joint problems and reproductive disorders.
While most dogs are content with their routine servings of commercially available dry or canned food, some animals develop an unpleasant and potentially harmful fondness for consuming nonfood substances. In this regard, the most common canine eating disorders are pica and coprophagy, the causes of which are not well understood.
This eating disorder is marked by the habitual consumption of indigestible nonfood items, ranging from rocks, pebbles, coins, rubber bands, socks and shoes to screws, nails and golf balls. Clearly, this habit is dangerous and can be fatal. Stones, rocks and other large, sharp objects can damage a dog's teeth and block or tear its stomach or intestines. Various metal objects can contain toxic levels of lead or zinc. In some cases, risky surgery must be performed to remove an object from an animal's digestive tract. While pica does occur in animals that are deficient in phosphorus or salt, the probability of such deficiencies is virtually zero in dogs that are fed commercial dog foods.
The occasional, or in some cases habitual, consumption by a dog of its own feces or those of another animal is a largely inexplicable activity among canines. It occurs not uncommonly in puppies that are confined in crates for extended periods of time. According to Dr. Kallfelz, stool eating, which occurs among mature dogs as well as puppies, is generally harmless, although certainly unpleasant to witness. However, the habit can conceivably pose serious health risks, since the animals that engage in this behavior may ingest harmful parasites that thrive in fecal matter.
Even abnormal eating-related patterns that do not physically imperil a dog can be objectionable and disruptive in a family situation. For example, a dog might constantly beg for food, be annoyingly fussy or habitually wolf down his food as if every mealtime were his last. Or he might be more interested in stealing food from the kitchen counter or dining room table than in eating what's given to him.
Annoying eating behaviors merit an owner's concern and pursuit of a remedy just as much as those that present a potentially significant health threat. In some cases, Dr. Kallfelz says, consultation with a veterinary nutritionist will be productive in resolving such problems. In other cases, he says, the services of an animal behaviorist maybe necessary.