Here is the article on diarrhea. Sandy
Sudden Diarrhea in Dogs
Robert Silver, DVM, MS, CVA
Laura Duclos, PhD
Dietary indiscretion remains the number one cause of acute diarrhea in dogs. Indiscretion is a term used to describe overeating, eating too fast, rapidly switching food, or eating inappropriate food. Two classic examples are pets accidentally getting into the garbage or being fed table scraps around the holidays. However, it is not uncommon for pets to develop acute diarrhea if they are overfed or are switched to a food with a different or higher nutrient density without a slow transition.
Diarrhea is a physical symptom; it is not a specific disease. Most often, diarrhea is a normal process that the body uses to try to rid itself of an offending agent. There are numerous causes of diarrhea in dogs and not all of the causes are disease or infection related:
• Non-infectious
o Dietary
o Physiological Disorder/Disease
o Toxins/Drugs
• Infectious
o Bacteria/Viruses
o Parasites
Diarrhea is the production of stool that is not formed, ranging from mild symptoms of a stool that is too soft to pick-up to the extreme situation where the stool is all liquid. To understand how diarrhea occurs, it is important to understand how a healthy intestine functions. In a normal intestine, food is broken down from its original solid or semisolid consistency into a liquid consistency that then allows the nutrients it contains to be absorbed into the body through the intestinal wall. The bowel continually moves digested material from the stomach down through the colon to the rectum. Undigested food or excess food passes into the colon where water is re-absorbed and the resulting solid material is passed out as feces. Throughout this whole process, the healthy intestine maintains the correct balance of electrolytes, nutrients, solids, and liquids. Any change to the normal function of the intestine, may cause acute (or rapid onset) diarrhea.
To pinpoint the cause of the diarrhea your veterinarian will conduct a series of diagnostic tests. The microscopic examination of the stool will determine if bacteria or parasites are responsible for your pet’s diarrhea. An important part of your veterinarian’s analysis of your pet’s diarrhea problem also includes a detailed dietary history. Dietary factors are the most common cause of non-infectious diarrhea. Your veterinarian will also review your pet’s medications and supplements. Some drugs or supplements may speed up or slow down intestinal motility or may impair fluid absorption. These could also potentially create or influence your pet’s stool problems. Blood tests can help to rule out specific disorders that can lead to diarrhea. Specifically one blood test, the cTLI test measures your pet’s pancreas’ ability to secrete digestive enzymes. In the absence of these enzymes, soft stools or diarrhea can result.
Even with the many number of possibilities that might cause diarrhea as listed above, diet-related factors are the single most common cause for soft stools and diarrhea.
With severe diarrhea we may also observe blood in the stool. This is usually red, frank blood, as compared to dark tarry-looking stools. Fresh blood in the stool is associated with irritation or inflammation in the colon and rectum. When the stool is dark and tarry it means that the bleeding is higher up in the GI tract. Most commonly this occurs with the kind of intestinal bleeding we see with the use of non-steroidal anti-inflammatory drugs (NSAIDs) such as Rimadyl? or Deramaxx?.
The primary function of the small intestine is to absorb food nutrients. When nutrients are present in excess, the bowel is overwhelmed; it is unable to secrete enough enzymes to completely digest the food; the gut wall cannot effectively absorb all the nutrients of the food that has been digested. Thus, a great deal of food remains partially digested and unabsorbed. Additionally, as a protective and natural cleansing mechanism, and to help balance the pH and osmotic pressure in the bowel, the body dilutes the excess nutrients with more water and moves it through the gut at a faster rate. This results in loose stools or diarrhea because of the rapid transit of digested material through the lower bowel. The large bowel or colon, simply doesn’t have enough time to re-absorb the excessive digestive fluids that have resulted from its having been overwhelmed by excess nutrients.
Other than feeding your pet something new from your table, other sources of excessively rich nutrition can be derived from switching from one pet food to another. Nutrient densities in pet food vary from brand to brand. There may even be variation from batch to batch within a brand. Pet nutrient profiles are regulated by AAFCO, which requires that manufacturers maintain consistent nutrient profiles for given types of pet food. Occasionally pet food manufacturers may change the manufacturing process in order to create a better product. It is important to note that they are not allowed to change the nutrient profile or ingredients for that food without concomitantly changing the packaging. Despite differences in manufacturing between pet food plants, it is possible to create a pet food that identically matches the same food that had been manufactured at another plant. However, due to subtle differences in manufacturing practices and equipment, occasionally a diet is produced that matches its registered AAFCO profile, but which, due to the change in manufacturing may cause soft stools, diarrhea, even bloody diarrhea and vomiting. The magnitude of the difference between the 2 foods combined with the overall health status of the pet often will be reflected in the severity of the diarrhea or vomiting. Usually once the feeding of this food is discontinued or the pet becomes accustomed to the change, these symptoms resolve very rapidly.
There are three main causes for changes in the nutrient density of a dry pet food:
1) Raw material variation – natural ingredients will vary from lot to lot. Each ingredient has a typical profile, but profiles for any individual lot will vary within the minimum and maximum levels allowed.
2) Kibble density (or lbs of food that can fit in a defined volume) – a kibble that has a density of 26 lbs/ft3 takes up more space than one with a density of 36 lbs/ft3. One cup of kibble with a density of 26 lbs/ft3 weighs 115 grams but 1 cup of kibble with a density of 36 lbs/ft3 weighs 145 grams – nearly 20% more weight per cup. The percent composition (guaranteed analysis) of the 2 kibbles remains the same, but the percentage is based on a weight. Therefore, feeding a higher density of kibble means that the pet would consume more nutrients per serving compared to the lower density kibble. Practically, what this means is that less food can be fed to deliver the same amount of nutrition for your pet.
3) Percentage of cooked starch – when starch is cooked in the extruder, it gelatinizes and becomes more susceptible to digestive enzymes; it becomes easier for the pet to digest. For example, a kibble with a “70% cook” means that 70% of the food’s starch content has been gelatinized and can be broken down by the body’s digestive enzymes. The remaining 30% of the food’s starch content (the un-gelatinized portion) may not be completely digested and pass out in the feces or be fermented by colonic bacteria. As the percentage of gelatinized starch increases, more starch nutrients can be broken down by the body.
Food density and percentage of cooked starch are more likely to be causes of diarrhea than raw material variation. When food density and percentage of cooked starch are both involved simultaneously the diarrhea may become persistent and severe. If only one aspect is involved, the diarrhea is typically short term and resolves.
When a dog develops diarrhea from too rich a diet, it is important to withdraw the food, and offer a bland, binding diet of cooked white rice and cooked chicken or lean beef. The addition of healthy probiotic bacterial cultures such as Lactobacillus acidophilus can help to normalize the bowel and allow it to return to healthy stool production much sooner. If the diarrhea persists for more than 48 hours after the food has been pulled, it is important for the animal to be seen by a veterinarian. Food may be re-introduced using a slow transition after the dog has stabilized and normal stool is produced consistently for several days.
References
1. Hand, M.S., et al., Small Animal Clinical Nutrition. 4 ed. 2000, Topeka, KS: Mark Morris Institute. 1192.
2. National Research Council, ed. Nutrient Requirements of Dogs and Cats. Animal Nutrition Series. 2006, National Academies Press: Washington, DC. 398.
3. Wills, J.M. and K.W. Simpson, eds. The Waltham Book of Clinical Nutrition of the Dog and Cat. 1994, Elsevier Science, Ltd.: Tarrytown, NY. 472.
4. Aiello, S., ed. The Merck Veterinary Manual. 8 ed. 1998, Merck & Co, Inc.: Whitehouse Station, NJ. 2305.
5. Waltham Center for Pet Nutrition, The Canine Gastrointestinal Tract: Small Intestine, in The Waltham Course on Dog and Cat Nutrition. 1999, Waltham.
