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Ferrets seem to have been designed to challenge the diagnostic abilities of veterinarians. That said, a wide array of gastrointestinal (GI) disorders is seen in ferrets.
Like much of the rest of ferret medicine, GI disease is a bit of a gray area where there still is more to be learned than we actually know. That means a lot of veterinarian’s diagnoses and therapies involve some educated guesswork and good old-fashioned trial and error. Ferrets are walking GI disasters yet disease is common; nonetheless, the vast majority of cases are readily solved.
Having owned over 50 of my own ferrets through the years and treated thousands more, I am thoroughly convinced that every ferret has some diarrhea on an intermittent basis. The significance of that diarrhea depends on the severity, frequency, and overall impact on the health status of that individual patient.
Unfortunately, ferrets are blessed with an ultrashort intestinal tract and plentiful diets that are not designed with the ferret GI tract in mind, which is a recipe for severe and chronic GI disease. The transit time from end to end is only 3-4 hours, and the ferret is an obligate carnivore: they have little tolerance for the sweet treats offered by owners and the high-carbohydrate foods on the commercial market. From end to end, the ferret was designed and built to be an efficient predator, well adapted to a carnivorous lifestyle. Unfortunately, the commercialized high-carbohydrate kibbled diets are not compatible with their anatomy and physiology, and likely contribute to the extremely high incidence of GI diseases seen in pet ferrets. In large part, we do just about everything wrong when we feed our pet ferrets, and this comes to light in typical ferret fashion with chronic disease.
Perhaps the most common finding associated with GI disease in ferrets is diarrhea. Ferrets are little diarrhea machines, and since the GI tract is short, regular and severe diarrhea can rapidly lead to dehydration in as little as 3-4 hours. Not only is ferret diarrhea often frequent and profuse, it is colorful. Shades of neon green are not unusual to see, as well as bright mustard yellows, sunset reds, and black tar.
Dental Issues Relate to GI Disease
Dental disease is a nearly universal problem with older ferrets, and may be prevented by regular oral hygiene by owners. This can be challenging however, given the complete inability of most ferrets to sit still for more than a few seconds at a time, so healthy chew treats are sometimes substituted.
Ferrets have 34 permanent adult teeth. The canine teeth are designed to puncture and grip their prey. The fact that these are capable of delivering such a powerful and often fatal bite is a testament to the gentle personality of our ferrets – we rarely get treated to more than a mere nip of these strong teeth. Damage to the canines is common, particularly in animals housed for too long or too frequently in cages, as bar biting is a common result of cage frustration and can lead to fracture or breakage of these teeth. Dental pain, however, does need to be ruled in or out when working up a GI case, particularly if the ferret is not interested in eating.
In my clinical experience, it appears that ferrets fed exclusively a commercial kibbled diet often have the most severe dental disease. Those fed a balanced homemade diet combined with small amounts of kibble appear to fare better. Some dental health proponents recommend an "all prey" diet for ferrets. I do not have a large enough database of ferrets fed prey-based diets to have an opinion on this relative to dental health, but I can say that my own ferrets who ate prey for treats did have reasonably good oral health. Also, from my personal experience, the most effective dental treat appears to be N-bone Chew Treats. I have fed and recommended them for years, and believe that they do work.
However, there is no substitute for a good diet, avoiding sugary treats, and providing oral hygiene. I generally prepare owners for the eventual need for professional veterinary dental cleaning as their young ferret matures; periodontal disease can be seen by the age of 2-3 years.
The Digestive Tract and Diets
Like other carnivores, ferrets have a short digestive tract. Start to finish, the digestive tract is three to four times the length of its body, while an herbivore (such as a cow) has one greater than ten times the length of its body. Therefore, domestic ferret food only takes about 3-4 hours to digest.
This translates into a lot of poop! New ferret owners are often surprised – and dismayed – by the frequency and volume of ferret stool, but this is a normal and unavoidable byproduct of the short digestive tract. Many products supposedly reduce the odor of the fecal matter; however, my experience has been that the odor is best reduced when a high quality, non-fish-based diet is used. Strong and offensive stool odor, or changing odor, in the face of good husbandry and diet is cause for concern. I have seen a few ferrets with significant GI disease whose stool smell could outrank a skunk!
One of the arguments in favor of raw diets is that the short GI transit time helps to prevent food-borne bacteria (such as Salmonella and E. coli) from affecting the ferret, but I am not sure that there is much evidence to substantiate that claim. Additionally, ferrets with GI disease may have an altered transit time. Although from a physiological and anatomical standpoint there are strong cases to be made for a prey-based diet in ferrets, there are also risks.
I am firmly of the opinion at this point in time that we really don't have a perfect diet available for ferrets that meets all of their anatomic and physiologic needs as well as the desires of their owners; we simply have an array of compromises to choose from. For my ferrets, I use a blend of four or five different high-quality ferret kibbled foods from several different manufacturers and several different protein sources, and hope to strike the balance through diversity.
Ferrets have a large, simple stomach, which is designed to hold a huge meal followed by a period of fasting; however, if you look at a ferret's behavior, it will typically eat small meals frequently, like a cat does. The small intestine and entire colon are very short. The diameter of the small intestine is also small, which can cause considerable problems given the proclivity of ferrets to snack on everything rubber or foam that they find, from remote controls to kid's toys. That short colon helps explain why diarrhea is such a common problem in ferrets!
Ferrets will get into anything and everything – so once again, don't assume. Once my entire business of 14 ferrets got into my office (allegedly off limits) and into the top drawer of my desk (are you picturing a pyramid of ferrets right about now?). There, they managed to find a non-childproofed bottle of ibuprofen, which they chose to open and proceeded to lick all of the coating off the 70-plus tablets in the bottle. That evening we had 14 ferrets hooked up to IV fluids in my living room. The determined ferret can outsmart almost every human pet-parent around (including me). Do not underestimate the power of the ferret!
Symptoms of GI disease vary amongst ferrets and are largely non-specific. Perhaps the most common complaint, not surprisingly given their anatomy/physiology, is diarrhea. What might be surprising, though, is that the only sign for some conditions, such as foreign body ingestion, might be reduced appetite and diarrhea! This can make it challenging to your veterinarian to determine whether an animal with loose stool has a mild gastroenteritis that can be addressed symptomatically, or a more serious disease that warrants an exploratory surgery.
A common symptom of GI discomfort includes grinding their teeth (bruxism). Sometimes it will be the only sign. Individual ferrets are more or less sensitive to discomfort, and what might result in tooth grinding in one patient will not in another, making it difficult to assign importance to this finding.
Similarly difficult is the symptom of vomiting. Some ferrets are sensitive to gastric inflammation and will profusely salivate and vomit with the slightest indication of gastritis, while others will have large gastric foreign bodies and exhibit no vomiting.
When to See your Veterinarian
See your veterinarian if your ferret seems lethargic, is vomiting, has significant diarrhea, or is grinding their teeth. Those are fairly obvious signs that a ferret is not well. However, if you notice changes in appetite, stool appearance, odor, and other more subtle changes, your ferret should also see the veterinarian. Sometimes those subtle changes can be the earliest signs.