Everything we know is a product of a nuclear reaction – deep within the sun and from collapsing stars going supernova – emerge larger and larger atoms and limitless energy. All of this is a process millions, if not billions of years in the making. What does this have to do with pets? Well, when your dog or cat’s butt goes nuclear, as many clients have said over the years, the fix will not be instantaneous. The planet didn’t coalesce from primordial materials in a day, and the dog’s diarrhea will not resolve overnight, either.
The body of most animals can be considered a tube. Think about it – food enters the mouth and journeys through the intestines and pops out the other end. Dogs have been known to eat a sock and unceremoniously defecate it out whole on the floor. It’s what happens within the tube — the intestines — that’s a bit of magic. This protected hollow tube capable is of absorbing and even digesting nutrients.
The intestines are longer than the body itself, coiling and folding to fit within the abdomen. A dog/cat’s intestines, as a general rule, are about 4-6 times the length of their body! This can range from about three feet for a Chihuahua to over 15 for a large Labrador! But the surface area of the intestine is much, much greater. On a microscopic scale, the inside lining of the intestine, the mucosa, is lined with billions of small fingerlike projections — villi, making the absorbing surface 500-1000 times greater than if the intestines were a smooth surface! For example if a medium-sized dog has about 10 feet of intestines, the absorbing surface area can be as great as 1000-2000 square feet, bigger than many people’s apartment!
Intestines perform many functions, with nutrient acquisition and water retention being the most well-known. Now that we see how great the surface area can be, it’s easier to understand that healing of a sick or diseased intestine isn’t an immediate process. Diarrhea can result from various causes, including damage to the intestinal lining. While damage can occur quickly with toxins and parasitic or bacterial infections, and more slowly with immune diseases and allergies, healing is variable and can take time.
After food exits the stomach, the small intestine’s villi take in nutrients. When damaged, the body in essence starves, although food intake may be appropriate, since absorption decreases. Further along the large intestine resorbs water, lessening the need to drink and producing a more firm, sanitary stool.
A pet with diarrhea isn’t always going to be better within the day. Healing takes time. Acute damage can heal within days, as the intestines are amongst the fasting healing tissues in the body, but resolution of allergic disease and autoimmune disease is prolonged.
Bland diets are used to give the intestines a break, while providing essential nutrition to regenerate the villi. Blandness may also be calming, requiring less digestive enzymes from other organs. Carbohydrates from rice may help to gum up stool too, producing a more solid product. Veterinary diets for acute diarrheas usually resolve or greatly improve stool within a few days. There’s magic in the diets, but they need time to work. It’s the more chronic cases where patience is needed.
Hydrolyzed and novel-protein diets may eliminate or greatly reduce allergens or compounds which cause irritation and intestinal upset. Changing a diet doesn’t produce immediate results, though. Intestinal regeneration and healing in chronic inflammatory bowel disease can take 6-12 weeks to regain normal structure, and even longer in severe cases, if ever. In addition to the villi regenerating, intestines are laden with bacteria, and these need time to adjust to new diets and conditions, too. Bacterial imbalance readily leads to diarrhea.
When a dog or cat has diarrhea, clients want an immediate fix. The problem is that it’s not so easy. Most diarrheas are managed successfully through diet manipulation, which takes time, but yields a much better long-term result than medications or antibiotics.
Dan Teich, DVM, is the Founder of District Veterinary Hospitals
