Anorexia in rabbits: 1. Causes and effects

Why rabbits may suffer from anorexia, and the effects it has on them

source: Frances Harcourt-Brown
In Practice vol 24 no 7 July/Aug 2002
starts p358, 8 pages long

Pet rabbits are often taken to the vets with anorexia, which may have a number of causes. They can die if the anorexia is left untreated, so it is important to diagnose the condition promptly. Treatment and diagnosis will be discussed in part 2.

Rabbits' digestive systems are geared to digesting a lot of fibrous food. Their digestive strategies include ingesting caecotrophs, or pellets containing vitamins, fatty acids, and amino acids, directly from the anus. Caecotrophs are also called soft faeces, and are usually expelled when rabbits are resting, while hard faeces are formed when rabbits are feeding. The excretion phases follow circadian rhythms, which can be affected by a number offactors such as stress, food type, lactation, and age. Caecal microflora are important for absorbing and producing volatile fatty acids. They can be affected by antibiotics. Gut motility is important for digestion, and can be affected by several factors such as fat and carbohydrate levels in diet. High fibre diets have a beneficial effect on gut motility, stimulate caecotrophy and appetite. Giving rabbits hay to eat can prevent boredom, and help prevent them from eating things that could harm them, like carpet fibre.

Stress can affect digestion in a number of ways, such as inhibiting gut motility. Rabbits that are affected by slow gastric emptying may suffer dehydration, and the stomach contents may become impacted. Slow gut motility can lead to pain as gas is accumulated, and pain can in turn increase stress. Rabbits may also suffer from acidosis, and anorexia and depression are common among rabbits with ketoacidosis, which is stress-related. This can result in kidney and liver failure if left untreated, and lactating and pregnant does are especially vulnerable.

Rabbits may also suffer from problems with their teeth and gums, and dental problems may lead to wounds on the rabbit's tongue. Dental problems may have a number of causes, including teeth being clipped incorrectly.

Caecal impaction can result from rabbits eating cat litter. They may also suffer from intestinal obsructions, especially breeds with long hair, which may ingest hair as felted pellets while grooming themselves. The effect of ingesting hair can be sudden. Dried pulses can also obstruct the intestine. Young rabbits may also suffer from mucoid enteropathy, with diarrhoea and mucus excreted, and the rabbit grinding teeth, possibly as a result of pain. Enteritis can be found in lab rabbits, though is less often found among adult pet rabbits. Kidney disease can also lead to anorexia, and may be caused by parasites.

Lab investigations, exploratory surgery, and radiology may be needed to assess the cause of anorexia, but these are the most common causes.