Diarrhoea – Rabbit

“Diarrhoea syndromes”

It is important to assess the material being produced that gives rise to the above title! See assessment of faeces below. It is amazing how many veterinarians confuse polyuria in rabbits with diarrhoea. Owners often confuse the occurrence of uneaten caecotrophs with diarrhoea in their pets. It’s better to react to variation in the nature and production of faeces and consider such clinical entities as clagged vent – the passage of copious amounts of caecal material from the anus. This may be found adhered to the vent area. The caecotrophs may not been ingested because of non-gastro-intestinal causes (dental overgrowth, spinal deformities, etc).

“Diarrhoea” is rare in pet rabbits, especially adult ones and may result from enteritis which occurs in decreased gastrointestinal motility (constipation). So the appearance of the fluid stool of the carnivore with diarrhoea may not be seen in the similarly afflicted rabbit. In fact, the production of large masses of solid faeces is a more usual presentation, adhered to the vent and not removed by the animal.

If there are normal hard faecal pellets in the animal’s environment, the condition is not diarrhoea.

	Uneaten caecotrophs	Diarrhoea
Life threatening?	No	Yes, due to fluid and electrolyte disturbances
Frequency of production	Once or twice a day	Several times a day, often mixed with mucus
Hard faeces?	Yes - often normal production	No, only unformed stools seen
Anorexia	No	Yes
Depression	No	Yes
Smell	Strong - risk of fly strike	Variable
Owner reaction	Maybe over-react, due to smell	Probably slow, due to comparison with monogastric species.

Causes of Clagged Vent (Un-ingested caecotrophs)

Reduced appetite for caecotrophs

• High protein diet
• Low fibre diet
• Ad libitum feeding
• Taints
  • plants altering odour

Illness

• Physically unable to reach or groom perineum
  • Musculoskeletal problems
  • Neurological disease (eg. E cuniculi)
  • Spondylitis/kyphosis/arthritis
  • Abdominal masses
  • Large dewlap

Pain associated with ingestion of caecotrophs

• Urine scalding
• Dermatitis
• Infected perineal skin folds
• Dental disease

Husbandry

• Small cage
• Obesity
• Elizabethan collar
• Fluffy coat
• Interruption of daily routine, eg:
  • feeding times
  • photoperiod
• Stress
• Change of diet

Treatment of conditions involving uneaten caecotrophs

Rabbits stop eating their caecotrophs (probably because of the excess of dietary protein but the animals may be unable or unwilling to groom because they have overgrown teeth with sore mouths or tongues). Harcourt Brown (2002) differentiates between conditions in which the caecotrophs are normal or soft and lists different causes of the two conditions. This is not diarrhoea (although owners often mistake it as such. As caecotrophs are so sticky there is quite an accumulation of matter at the vent on which the rabbit then sits, thereby impacting the matter onto the surrounding tissues. The presenting clinical signs may include blow-fly myiasis.

The treatment is to lower the energy and protein content of the diet and to feed higher amounts of fibre (hay and straw). Restrict pellets to 10-20 gram per kg (20 g in fat rabbits for fear they become acetonaemic). You often have to be very strict with owners, as in the treatment of canine obesity. Antibiotics may have very little use in the treatment of these animals but concomitant infections (eg respiratory diseases) may have to be addressed, in which case I recommend oxytetracycline S/C q 72hrs (Engemycin 5%; Intervet). To stimulate the resumption of gut motility the use of cisapride (Prepulsid;Janssen Cilag) 6-8hrs is recommended but may be difficult to obtain so metoclopramide may be used instead - PO q12h. Ranitidine (PO q12h) is mentioned as a substitute for cisapride.

Acute diarrhoea of the young, newly acquired rabbit

This is associated with dysbiosis of the caecum and may be compounded with installation of, for example, E. coli, Clostridia, Salmonella, Yersinia spp.

Treatment with appropriate antibiotic (administered parenterally), fluids, antispamodics, analgesics, warmth.

In young specimens, especially at or soon after weaning, the subject is usually found depressed often to the point of coma with slightly cyanosed extremities (due to the fur this may be visible only in the ears, on the muzzle, and around the vent). The doe is usually perfectly normal. Muco-gelatinous faeces are frequently observed in which significant levels of coccidial oocysts or nematode eggs may or may not be found. The strong likelihood of the presence of the ubiquitous Pasteurella multocida together with the poorly developed and compromised immune system of the juvenile animal must be consid¬ered and the owner given a poor prognosis.

These animals are usually badly dehydrated so the subject is immediately hospitalised in a warm cage (no higher than 25°C under an overhead infra-red lamp) and 50 – 100 ml warm Hartmann's Fluid are administered by intraperitoneal injection together with suitable antibiotic cover (in the absence of antibiotic sensitivities, I use metronidazole (an unauthorised product, a 0.5% infusion, is available from Millpledge) and hyoscine/dipyrone (Buscopan Compositum; Boehringer Ingleheim). Care should be taken not to mix these analgesics with NSAID's for fear of toxicity but other analgesics (opioids) may be used instead. The danger of using hyoscine is that there could be some intestinal immotility which could lead to more absorption of toxins from the gut. Consideration should be given to the use of xylazine as a visceral analgesic. Parenteral oxytetracycline (Engemycin 5%; Intervet) 72 hrs should be given to cover against endemic pasteurellosis and can be used simultaneously with metronidazole.

The animal is kept in the warm environment until recovery is clinically evident. Hydration is maintained (at least 50 ml/kg daily in divided doses, of either warmed Hartmann's Solution intraperitoneally or a solution of Liquid Lectade® (Pfizer) diluted 1:11.5 in potable water and administered by stomach tube). Probiotics (I use Avipro made by Vetark, in spite of little evidence in the literature that Lactobacillus is a commensal of the normal rabbit caecum) are useful because the rabbits often appreciate the taste and thereby take in adequate amounts of oral fluids. The use of antimicrobials and intensive care (fluids etc) may be extended for up to four days at the clinician's discretion (or the client's direction which is often based on economic exigencies) but if there is going to be any improvement it will usually occur within the first twenty-four hours.

The prognosis for this syndrome must be very guarded especially if clostridial entertoxaemia or viral, enteric infections or protozoal infestations are involved. Microbiological examination of faeces will help to identify the secondary infections, but the urgency of the case, especially as it frequently presents in the newly acquired pet, often precludes such procedures. Spirochaetes have been incriminated in one outbreak of fatal enteritis in a colony of young rabbits (Tribe et al 1989). Readers will be aware that the growth of Clostridium species requires anaerobic conditions (Carman et al 1983).

References

• Carman et al (1983) Laboratory diagnosis of Clostridium spiroforme-mediated diarrhoea (iota-enterotoxaemia) of rabbits. Veterinary Record, 113.
• Tribe G.W. et al (1989) Fatal enteritis in rabbits associated with a spirochaete. Veterinary Record 124, 595.