Keeping Your Rabbit’s Digestive System Healthy
Rabbits are herbivores, meaning they only eat plants. They have a specialized gastrointestinal (GI) tract to accommodate that diet. Did you know rabbits can eat up to 30 times per day and ingest 2-8 grams of food per meal? Did you know rabbits can’t vomit? Did you know rabbits produce 2 types of feces and ingest one type? Continue reading to learn more about your rabbit’s GI tract, how to keep it healthy, and potentially serious issues if their delicate GI tract gets thrown off course.
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Anatomy of the Rabbit Digestive Tract
Rabbits have a single stomach (cows have 4!), small intestines comprised of 2 sections called the jejunum and ileum, and the large intestines comprised of the cecum and a specialized colon that can separate out food particles allowing the rabbit to retain the good fibers.
Rabbits have a rather fast GI transit time, meaning from the time food is ingested it can be processed through the entire GI tract in about 19 hours.
Rabbits will ingest plant material, chewing the food up to 120 times per minute, then they swallow the food where it passes through the esophagus into the stomach.
The stomach has 2 sphincters, one at the entrance and the other at the exit into the small intestines. The entrance sphincter, called the cardiac sphincter, is very strong and prevents rabbits from vomiting. The stomach excretes acid and pepsin to start breaking down the food. The pH of the stomach is very acidic compared to humans. Food should leave the stomach within 3 to 6 hours and move into the small intestines.
Once the food material is in the small intestines, the body can start to absorb nutrients such as lipids, electrolytes, and amino acids. Food passes quickly through the small intestines and into the cecum, it only takes about 30 to 60 minutes. The small intestines also secrete a substance called bicarbonate that neutralizes the high acid level that was introduced from the stomach.
The end of the small intestines enlarges into an area called the sacculus rotundus and is made of primarily lymphoid tissue. There are smaller patches of lymphoid tissue throughout the small intestines called Peyer’s Patches. These areas of lymphoid tissue are important in immune health overall, so keeping the GI tract healthy is critical in keeping the entire immune system healthy in your bunny.
Large Intestines and Cecum
Next, the food enters the large intestines and moves into the cecum. The cecum functions to breakdown digestible fibers and starches via fermentation and contains good microorganisms. If the good bacteria is altered, it can lead to an overgrowth of pathogens called dysbiosis, which can be fatal. The cecum can hold 10 times more material than the stomach, and, on average, 40% of the food material is in the cecum at any given time. Some nutrients are then absorbed through the cecal wall and others are formed into cecotrophs and eliminated rectally so the rabbits can ingest them. Keep reading to learn more about cecotrophs!
The beginning of the colon, called the proximal colon, separates the food material into digestible and indigestible material. The digestible material is then moved backwards into the cecum and the indigestible material is formed into fecal balls and moved out of the GI tract. The large intestines are also critical in water resorption.
The rabbit will produce 2 types of feces, the hard-feces and the soft cecotrophs. The hard feces pass during or shortly after eating. The smaller and softer cecotrophs are often passed at night or at least 4 hours after eating. The rabbits will ingest these directly from the anus. The cecotrophs contain good bacteria and nutrients and are critical to keeping the GI tract healthy and functioning.
Additional Information and Potential GI Issues in Rabbits
As you can see, rabbits have a complex GI system and all parts need to work together to function and keep your bunny happy and healthy. An inappropriate diet, lack of exercise, stress, and certain antibiotics can cause alterations to the GI function, motility, and flora leading to severe illness and potentially death.
Rabbits can form hairballs and unlike cats, they can’t vomit them back up. This means a lot of hair in the GI tract can lead to an obstruction in the stomach or small intestines. Be sure to brush your bunny regularly to remove as much loose hair as possible to limit ingestion.
Rabbits can also develop an obstruction in the large intestines from cecoliths. These are aggregates of hard and large cecal material. The cause is not fully known, but dehydration and nerve disorders are possible underlying causes that lead to a delay in the movement of the GI tract.
Stress can lead to an imbalance in the GI bacteria colony. A type of bacteria called Clostridium can cause watery diarrhea and death in young rabbits. Some adults will develop a chronic form of Tyzzer’s Disease, leading to chronic weight loss and even damage to the heart, liver, and intestinal wall. Treatment, if instituted early, can be lifesaving.
Finally, rabbits can also get intestinal parasites, viral diseases that affect the GI tract, and other bacterial infections that can cause severe illness.
Be sure to bring your bunny to the vet immediately if you notice any reduction in appetite, water intake, diarrhea, or lethargy. Rabbits are prey species and will hide illness until they’re very sick so there is no time to waste!
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