In adult rabbits, diarrhoea is quite uncommon. Several conditions can cause diarrhoea, with infections more common in young rabbits (kits/kittens). It is important to check your rabbit daily for diarrhoea as it could be due to a rapidly-progressing disease that requires early treatment or could lead to other problems such as flystrike.
What is diarrhoea?
Diarrhoea is the production of abnormally loose stools. When a rabbit has diarrhoea it will not only become dehydrated due to fluid loss, but will also lose other important substances such as electrolytes (salts like potassium and chloride) and nutrients, including vitamins. Clinical signs of diarrhoea include dirty fur around your rabbit’s bottom, which may lead to secondary skin problems, as well as weight loss, lethargy and a reduced appetite. The stools may be soft, semi-fluid or watery, and may contain mucus or blood in some conditions, and the rabbit may have a painful abdomen.
Pain in rabbits can be difficult to determine, since as a prey species they are programmed to hide signs of discomfort. Signs of abdominal pain may include bruxism (teeth grinding), pressing their abdomen on the ground or a hunched posture.
General treatment involve rehydrating the rabbit and re-establishing a healthy gut microbial environment. Nursing also includes care to prevent secondary skin problems.
Diarrhoea versus 'clagging'
Rabbits normally produce two types of stool, hard pellets and soft ‘caecotrophs’. These soft stools look like a small bunch of grapes and contain essential nutrients that the rabbit needs to eat every day. They are usually produced at night and eaten directly from the anus, so owners don’t see them. If your rabbit doesn’t eat their caecotrophs, it can be due to several reasons:
A sore back making it painful to be down.
Excessive weight, particularly around the dewlap or hindquarters.
If the rabbit doesn’t eat their caecotrophs, you may see them collecting at the anus, sticking to the rabbit’s fur and causing ‘clagging’.
Caecotrops are produced one to three times daily. They are soft but formed, and covered in a layer of clear mucus. Hard pellets are also produced in normal rabbits. Kits don’t produce caecotrophs until weaning age at 3-6 weeks old.
Conversely, diarrhoea occurs throughout the day, and stools are unformed and foul-smelling. The rabbit is usually depressed and off its food.
What are the common causes of diarrhoea in rabbits?
Some agents cause diarrhoea on their own, but many only cause problems in rabbits with other conditions, including other infections, digestive upset due to a low-fibre/high-carbohydrate diet, or with general poor health affecting the rabbit’s immune system.
Bacterial causes of diarrhoea are more common in young rabbits, e.g. Salmonella, Escherichia coli (E.coli) and Clostridium piliforme (Tyzzer’s disease). Some species of coccidian parasites (pathogenic Eimeria spp) can cause diarrhoea around and after weaning.
Viruses, such as retroviruses and coronaviruses, may cause mild diarrhoea on their won or more serious diarrhoea with bacterial co-infections.
Identification of the cause may require faecal tests to be performed, and often general treatment is started before laboratory results are available.
Besides the supportive treatment outlined above, specific antimicrobial medications may be required to treat these infections.
Why are kits more susceptible to diarrhoea than adults?
Adult rabbits have microbes in their gut to help digest food. Before weaning, kits have almost no microbes along their digestive tract. At weaning, the rabbit’s digestive tract changes significantly and it is particularly susceptible to infections around this time.
Why do some antibiotics cause diarrhoea in rabbits?
Antibiotics can affect the healthy microbes in the rabbit’s digestive system. Some antibiotics, especially those in the macrolide and lincosamide groups, alter the balance of microbes and allow overgrowth of organisms that can cause disease, eg clostridial bacteria. Giving certain antibiotics by mouth is more likely to affect the gut microbes than giving them by injection. Rabbits on a poor diet, which is low in fibre, and more susceptible to the adverse effects of antibiotics.
Milder cases of antibiotic-induced diarrhoea may have altered stools and reduced appetite, but in severe cases the altered microbes can lead to a generalised toxic state in the rabbit which may be fatal.
Why is diarrhoea associated with flystrike?
Flies like to lay their eggs in moist warm areas. If your rabbit has diarrhoea on its skin and in its fur, flies will attack this area, especially in warm weather. When the fly eggs hatch, the maggots will feed on material nearby. In some cases the maggots enter deeper tissues, and a toxic reaction can occur which is sometimes fatal.
It is very important to check your rabbit’s bottom frequently to ensure it is clean and dry. If your rabbit has diarrhoea, you will need to wash it to reduce the risk of flystrike.
What supportive treatment is useful?
Rabbits with diarrhoea rapidly become dehydrated, and need to take in additional fluid to replace those lost. You can encourage your rabbit to drink by offering fresh water in a convenient location. In some cases, fluids can be given via a dropper syringe into the rabbit’s mouth. More severe cases will benefit from veterinary administration of fluids, e.g. by injections under the skin or via a drip into a vein.
It is important to keep the rabbit’s digestive tract moving. In conditions affecting the tract such as diarrhoea, normal motility is often reduced. For this reason, medications called ‘prokinetics’ can be given to stimulate movement in the tract. One of the easiest ways to encourage movement is to give high fibre nutrition. If your rabbit is not eating, you can give a supplement by syringing special high fibre food paste mixes into their mouth.
Why is a good diet so important for my rabbit?
Rabbits need a high fibre to aid digestion; this stimulates gut motility and also helps wear down the rabbit’s teeth in a natural way. This should be made up of lots of good quality grass hay making up 80% of the rabbits diet, 5% good quality extruded nuggets and 15% fresh greens. Such a diet will help reduce the risk of digestive tract disease, including diarrhoea.