Okay, so pet poop is not a particularly pleasant topic, but a surprising number of pets have problems with constipation (abnormal accumulation of feces and difficulty defecating). More serious conditions can result from constipation, such as obstipation (complete obstruction of the colon by feces) and megacolon (damaged nerves and muscles in the colon causing an inability to defecate).
The colon, the last part of the intestinal tract, is a large muscular structure ending at the rectum. It contains most of the intestinal bacteria that reside in the gastrointestinal (GI) tract. These bacteria finish up the digestion of protein. By-products of this process include short-chain fatty acids that nourish the cells lining the colon. Some of these lining cells absorb water, while others secrete mucus to lubricate the stool and keep it moving along.
Constipation is uncomfortable, even painful. Dogs may have accidents indoors. Cats may defecate (or try to) outside the litterbox, because they associate the discomfort with the box itself. Other signs of constipation include straining to defecate, irritability, painful abdomen, lethargy, and poor appetite or even loss of appetite.
Most pets defecate once or twice a day. Dogs have a strong reflex that triggers an urge to defecate after eating; cats are a little less motivated. A constipated animal may only defecate every 2 to 4 days, or even less. Usually the stools are hard and dry, because their long stay in the colon allows for absorption of most of their water content. However, occasionally a constipated pet can appear to have diarrhea, because liquid stool is the only thing that can get around the stuck mass of feces.
Causes for pooping problems include congenital abnormalities, neurologic problems, pelvic injury, obstruction (by hair, bones, etc.), and inflammatory bowel disease (IBD). Dogs typically become constipated secondary to another issue, such as injury or surgery. Small breed dogs appear to have more problems than larger breeds. In cats, the cause often remains unknown, but even a dirty litter box may cause avoidance; constipation results from holding the stool too long. Hooded litterboxes are a particular problem because they hold odor in, potentially making the box environment extremely unpleasant for the cat.
The initial treatment for constipation is usually a change in diet. Historically, pets have been put on high-fiber dry foods. Fiber modulates intestinal mobility. Depending on the type of fiber and the circumstances, fiber can either speed up or slow down digestion. It’s therefore used for both constipation and diarrhea. Light, senior, and hairball foods all contain increased fiber, and there are also several medical high-fiber diets.
Changing to a high-fiber diet often helps, at least initially. However, eventually these foods seem to lose their effectiveness over time. More fiber, such as canned pumpkin, may be added. Again, sometimes this produces a temporary improvement. Yet many animals, especially cats, continue to have problems.
Since fiber encourages water absorption and increases the amount of stool produced (because it is indigestible), many experts have swung the other way and are now recommending “low-residue” diets to minimize stool volume. “Low-residue” means that the food is highly digestible and produces minimal waste; fiber is typically low in these diets.
Dogs and cats are carnivores who digest protein and fat best, but there is controversy about carbohydrates; it is clear that many cats are carb-intolerant. Carbs contribute to obesity in both dogs and cats, and obesity is common factor in constipation. By this theory, the best food would be high fat, high protein, and low fiber, as well as high moisture. One would think that such a food would also be low fiber, but that is not necessarily true; always check the Guaranteed Analysis (available for each food on our website). Most canned foods fit this description, as do most raw and homemade diets. Dry diets are higher in fiber than canned, and can cause dehydration in cats, contributing to the problem.
Treatment for constipation depends on the severity of the problem. For mild cases, occasional enemas may be all they need. For severe blockages, the animal must be anesthetized for manual extraction of the feces (a process my vet tech graphically but accurately refers to as a “dig-out”). Water balance is also crucial in constipated animals, especially cats. Subcutaneous (or even intravenous) fluids may be needed to boost their hydration.
Once the animal is “cleaned out” by whatever means, you’ll definitely want to take steps to prevent the problem from recurring. Several options are available; some animals may need only one of these, while others need a combination of several of them.
• Fiber. Because canned and homemade diets tend to be extremely low in fiber, addition of a small amount of ground flaxseed or powdered psyllium (available in bulk at most health food stores) may be needed for some animals. Flaxseed is an excellent choice because it also contains Omega-3 essential fatty acids, and its high content of lignans may help prevent some types of cancer.
• Herbs. There are many herbal formulas available for people, but many of their ingredients are too harsh for pets. Safe herbal formulas for pets include
• Lactulose. This is a syrup that holds water in the stool and keeps the stool soft; therefore it’s easier for the animal to pass. The taste, which is extremely sweet, can be an obstacle for some pets. Fortunately, lactulose now comes in a mild-tasting powder (Kristalose) that can be encapsulated by a compounding pharmacy, or simply added to canned food.
• Other stool softeners, such as DSS (docusate sodium). Your veterinarian can prescribe these.
• Petroleum jelly (e.g., Vaseline®). This is the primary ingredient in most over-the-counter hairball remedies (Laxatone, Kat-a-lax, Petromalt). Petroleum jelly can be given by mouth. Most pets tolerate it, many come to like it, and a few even relish it. Give 1/3 to 1/2 teaspoon per day for a cat or small dog, preferably separate from meals. It is completely harmless and inert in the body. (Vegetable oils do not have the same effect because they are digested and absorbed before reaching the colon.)
• Cisapride (Propulsid). This drug was withdrawn from the market for humans because of dangerous side effects, but it is considered safe for pets. Your vet can order it from a compounding pharmacy. It seems to work best in combination with stool softeners.
• Lubiprostone (Amitiza) was recently approved as a drug for humans. Your vet can advise you on whether it is safe and appropriate for your pet.
Note: Cisapride and Lubiprostone should not be used simultaneously)
• Pediatric glycerin suppositories. Although they may not appreciate having a suppository pushed into their rectums, most pets tolerate it. Your vet can advise you on technique and frequency.
• Enemas. Many pet guardians have (necessarily) gotten very good at giving enemas at home. Mineral oil, K-Y jelly (in a 1:1 ratio with warm water), soapy water, and just plain warm water are all fine; you may have to experiment to see which one works best for your particular pet.
• Fluids. Your veterinarian can show you how to give subcutaneous fluids at home if needed.
• Slippery Elm. This powdered herb can be added to canned food (add extra cool water) or made into a syrup. Its mild taste is well tolerated by most pets.
• Exercise. Obesity is a risk factor for constipation. Staying active prevents weight gain, and helps stimulate the intestines and keep things moving. Brisk walks and fetching games are great for dogs. If your constipated cat is also a couch potato, you can introduce regular play sessions with an interactive fishing-pole type toy, like the Kitty Lure Caster or Swizzle.
• Stress Management. There is always an energetic or emotional component of any chronic disease, and stress plays a significant role in many gastrointestinal conditions. Flower essences can be very helpful.
• Surgery. If there is damage to the nerves and muscles of the colon, a “sub-total colectomy” is the last resort. This surgery removes the colon, and joins the small intestine to the rectum. Unless and until the small intestine develops more colon-like functioning, the result is chronic diarrhea. However, the animal will be much more comfortable.
If your pet is chronically constipated, the most important thing for you to do is be observant. Look for early signs of constipation; straining, abdominal discomfort, decreasing appetite, etc. Be aware of how often your pet is defecating. If he does not produce adequate stool for more than 2-3 days, call your vet, or begin home treatments if you have established this routine. Constipation is far easier to treat when it’s caught early. Later on, treatment will be far more expensive, and there is a greater chance of irreversible colon damage.