Dog Diarrhea – Small and Large Intestines



This article is posted as part of PGAA’s curation efforts. This was originally posted at WayCoolDogs


Dog diarrhea in the small and large canine intestines is the most common of the dog problems. These problems are associated with three major symptoms: (1) dog diarrhea, (2) constipation, and (3) the passing of blood. Two of the most common causes of diarrhea are intestinal parasites and dietary indiscretion, along with canine infectious diseases – listed in the article. The hardest part is deciding if the diarrhea is in the small or large intestine.

Once a dog eats a meal, it takes about eight hours to be fully digested in the small intestine. The remainder of the food will concentrate in the colon, or large bowel. A normal stool has no undigested food, mucus, or blood in it. A rapid movement through the bowels results in the food arriving in the rectum in a liquid state, or dog diarrhea. Dietary indiscretion is the most common form of rapid transit, causing watery or loose diarrhea in dogs.

dog diarrhea

The best thing to do with dog diarrhea is withhold food for 24 hours to rest the entire GI. Image provided by Wikipedia Commons
Food intolerance that causes dog diarrhea

These are the major foods that cause a rapid transit of excessive stools

  • Beef
  • Pork
  • Chicken
  • Horsemeat
  • Fish
  • Eggs
  • Spices
  • Corn
  • Wheat
  • Soy
  • Gravies
  • Salts
  • Fats
  • Some commercial dog foods
  • Some dogs cannot digest milk and milk by-products. If the dog cannot digest it, it remains in the bowel and holds water, which forms large-volume (or projectile) diarrhea.

Other foods are scavenger foods: garbage, decayed foods, dead animals, grass, wild and ornamental plants, plastic, wood, paper and foreign materials or objects.

Dog diarrhea and intestinal parasites

Dog worms or parasites are a very common problem in dogs. It causes acute and chronic diarrhea in both adult dogs and puppies. The most common problems are with roundworms, hookworms, whipworms, threadworms and giardia.

Diarrhea diseases

The group of diarrhea diseases that can commonly affect the dog’s stomach and intestines are characterized by:

  • Chronic and protracted diarrhea
    • Chronic diarrhea and protracted diarrhea are two different things.
      • Chronic diarrhea is change in frequency, consistency and volume of dog’s feces for three weeks or more.
      • Protracted diarrhea (PD) syndrome consists of several diseases with diverse etiologies.
      • Both are characterized by clinical manifestations, the outcomes of PD and the spectrum of causes.
    • An analysis of clinical and pathological findings was performed on 25 dogs with diarrhea starting within the first 2 yrs. years of life and a requirement of parenteral (taken into the body in a manner other than through the digestive canal) nutrition (PN).
    • In conclusion, those with PD should be referred to specialized centers where advanced diagnostic and therapeutic facilities are available, because histological analysis is critical for the diagnosis of PD, and PN or intestinal transplantation is the only therapeutic option in a subset of cases.
  • Malabsorption
    • Diagnosing malabsorption can be complex. Long term diarrhea and weight loss are signs that are common in several diseases, one of which is malabsorption. An exact diagnosis may take more than a single visit to the vet. This is because a thorough examination is needed to study specific signs of malabsorption in order to determine whether the symptoms are caused by an underlying generalized or metabolic disease.
    • Symptoms of malabsorption are due to lack of nutrient uptake and loss of nutrients that pass through the feces. Signs include: (1) long term diarrhea, (2) weight loss, and (3) altered appetite (loss of appetite or excessive eating). Nonspecific signs may include (1) dehydration, (2) anemia, (3) dark blood in the stools, or (4) fluid retention.
    • There are certain tests to determine whether symptoms are due to a condition such as inflammatory bowel disease liver disease or parasites. Also, a dog’s history is particularly important. It suggests a specific food allergy, consumption of non-food items, or some other sensitivity. Weight loss may indicate malabsorption or a protein-losing disease. It is also due to (1) loss of appetite, (2) vomiting, or a (3) non-digestive disease.
    • There are specific features that help distinguish small intestinal diarrhea from large intestinal diarrhea. Suspected large intestine disease in dogs can be evaluated by a biopsy of the intestinal lining. If signs are accompanied by weight loss or large volumes of feces, then the small intestine could also be affected.
    • Treatment of malabsorption encompasses (1) dietary change, (2) management of complications, and treatment of the cause (if it can be identified). If malabsorption is caused by pancreatic insufficiency, treatment involves feeding a special low-fiber diet that contains moderate levels of fat or highly digestible fat, very digestible carbohydrate, and high-quality protein.
    • Providing supplements with pancreatic extract will provided missing enzymes if necessary. If the dog has a poor response to pancreatic replacement treatment, small intestinal bacterial overgrowth may be suspected. If so, the dog may be treated with oral antibiotics for about 1 one month in order to reduce bacterial overgrowth.
    • Effective treatment of the small intestinal disease for dog diarrhea depends on the nature of the disorder. But when a specific diagnosis cannot be made, treatments may be given on a trial basis. Dietary modification is an important aspect of the management of small intestinal disease. Your veterinarian may recommend feeding your pet an exclusion diet consisting of a single protein source (one to which your dog has not previously been exposed) as a test when dietary sensitivity is suspected. It is very important that you provide the special diet and prescribed medication(s) for your pet exactly as instructed.
    • Owners are tempted to provide a “special treat” not on the diet for dog diarrhea, even though they have been instructed not to do so. Failure to follow the prescribed diet can delay diagnosis and delay the treatment their pet needs. Owners can reward their pets during this time with petting, a new blanket or suitable toy, or some other reward that is not food. Often the best and safest reward for a dog is extended periods of attention.

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    You might also like:

    Chronic Dog Diarrhea and Vomiting
    Dog Diarrhea Ailment – Common in Dogs
    Giardiasis – Parasitic Diarrhea in Dogs, Cats and Humans
    Liver Disease in Dogs
    Toxic Foods for Dogs

    WayCoolDog posts originally appeared on WayCoolDogs and are re-posted with the permission of Nancy Houser of WayCoolDogs © 2009 – 2016