ABSTRACT: Dental disease is a common reason rabbits are presented to the veterinary surgery. Owners of rabbits often seek advice and support about the signs of dental clinical conditions, what causes them and the role they can play in their management. The veterinary nurse plays a key role in providing this support. Rabbits are prone to developing dental disease if their teeth, which continuously grow and erupt, are not worn down sufficiently. The clinical signs of dental disease most commonly include anorexia or reduced appetite and decreased faecal pellet production. Diet plays a key role in the cause, management and prevention of this condition in pet rabbits.

Owners of rabbits frequently require advice and support for their rabbits with dental disease. Veterinary nurses are very important in helping owners understand the causes, clinical signs and how they can manage their rabbits dental disease. This is a complex condition that is often life-long, so having the owner s full understanding and co-operation is important to optimise the welfare of the rabbit. This common problem in rabbits is multi-factorial and management of these cases can be rewarding, but also challenging.

All pet rabbits are descended from the European wild rabbit, Oryctolagus cuniculus. They have evolved to graze on European grasses. The ability to thrive on this diet while retaining their small body size is the result of complex and unique structural and functional adaptations. Their teeth continuously erupt, grow and are worn away throughout life and this makes them more susceptible to dental developmental problems.

Signs of dental disease

The typical general signs of dental disease in rabbits are listed in Table 1.

Figure 1: A rabbit with very few droppings

Why is dental disease a common problem?

As previously mentioned, rabbits differ from humans, cats, dogs and many other species in that their teeth continuously grow and erupt to compensate as the grinding surface is worn away throughout life. They are, therefore, susceptible to developing dental problems throughout their life span.

The teeth, ligaments around the teeth and dental bone are all dynamic living tissues that continuously change in response to dietary changes and aberrant behaviour. The onset of dental disease in rabbits is often multi-factorial. Besides diet, other causes include genetics (birth defects or breed predisposition), trauma (tooth clipping, fractured skull bones from falls), infection and, in rare cases, tumours of the face.

Rabbit teeth are open rooted and continuously growing and erupting throughout life in the healthy rabbit. The rate of growth and dental wear is variable, but is on average 2 to 2.5mm a week for the incisors and 2.5 to 3mm a month for the cheek teeth. The duration of grazing and abrasiveness of the diet are important factors in ensuring sufficient dental wear.

Grass is highly abrasive, containing silicates and other materials – to varying degrees, depending on the species and habitat – and is, therefore, important in providing tooth wear.1 It follows, therefore, that the development of dental disease is common in rabbits fed diets low in hay and grass.

Rabbits fed muesli mixed diets tend to feed selectively and favour flaked peas and maize that are high in starch and low in calcium. If these rabbits do not eat any hay or vegetation they are at risk of chronic hypocalcaemia, which may lead to dental abnormalities. This problem can then be amplified if they are not exposed to any ultra-violet light.

Muesli mixed rabbit diets, therefore, are not recommended. An ideal diet involves offering a small amount of a commercial rabbit pellet food that will help provide the vitamins and minerals to supplement a healthy diet of fresh hay, grass and vegetation.

Diet in the management of dental disease

Changing the food fed to the rabbit to a diet that encourages the normal pattern of chewing action and efficient, even wear of the teeth can play a significant role in the management of dental disease in rabbits.

The normal pattern of chewing in rabbits has been found to involve a complex figure-of-eight lateral jaw movement during the cheek teeth grinding phase and this is seen when the rabbit is chewing natural vegetation (Figure 2). When unnatural foods are eaten – such as commercial rabbit foods (pellets or muesli) – the chewing action is much more vertical, altering the pattern of tooth wear (Figure 3).

Figure 2: The normal pattern of chewing in rabbits has been found to involve a complex figure-of-eight lateral jaw movement 

Figure 3: When unnatural foods are eaten, the chewing action is much more vertical.

Rabbits fed on diets low in abrasive particles, together with foods they can eat in a short period of time, are the most likely to predispose to uncontrolled elongation of the teeth.

For rabbits with significant dental problems, remedial treatment under general anaesthesia will be required; followed by a change in diet gradually over a two-week period to a food that is mainly hay and/or fresh grass, a handful of leafy vegetables twice daily and only one tablespoon of a commercial rabbit pellet. This will encourage the rabbit to spend longer periods chewing the abrasive hay which will encourage normal chewing action and proper dental wear.

Rabbits with mild dental disease may not need further dental treatment under general anaesthesia and those with moderate dental disease may need less frequent treatment appointments. Regular check-up appointments – at least every three to four months, depending on the severity of the dental disease – are recommended because the dental condition can change.

Rabbits with severe dental disease – and that are unable to chew normally – will need to have a specialised diet which they can eat. This will usually include a herbivore high fibre recovery diet fed as a porridge, bite-sized chopped salad and commercial rabbit pellets that they can swallow, to ensure they can eat enough for maintenance of health and well-being. 

These rabbits will continue to need regular dental treatment under general anaesthesia.

Can dental disease be prevented?

Rabbits with normal healthy teeth, dental ligaments and bone, which are given a healthy balanced diet that encourages good dental wear and normal chewing patterns, should not develop dental disease.

When rabbits are fed a diet that they can consume over a short period of time and are not offered alternative foods to chew on, they will start chewing inappropriate items and they will spend less time grind
ing food that will wear down their teeth.

Rabbits in the wild spend a considerable amount of their time foraging. Offering less commercial food and more hay or grass will increase the time they spend grinding abrasive food to wear down their teeth, reduce boredom and increase the amount of energy the rabbit utilises to obtain its daily calories. This will also help beat the growing trend towards obesity in rabbits.

The more a pet rabbits diet varies from 100 per cent natural mixed meadow grazing, the greater the predisposition to dental disease and other problems. 

Author

Brigitte Lord

BVetMed (Hons) CertZooMed MRCVS

Brigitte graduated with Honours from the RVC, London in 2002. She was appointed as the first Rabbit Welfare Fund Rabbit & Zoo Animal resident in the UK in 2004, based at Bristol Zoo and the University of Bristol. She ran a rabbit and exotic veterinary referral service in the South West and returned to Edinburgh, R(D)VS in 2008 as a lecturer in rabbit medicine and surgery.

To cite this article use either

DOI: 10.1111/j.2045-0648.2011.00136.x or Veterinary Nursing Journal Vol 27 pp 18-20

Reference

1. CROSSLEY, D. A. (19971 Rabbit Dentistry. In: Midwest Exotic Pet Seminars. Chicago.

Further reading

CROSSLEY, D. A. (2004) Smalt Mammal Dentistry.

In: Quesenberry K. E., Carpenter, J. W. Eds. Ferrets, Rabbits, and Rodents. 2nd ed. Saunders, Missouri, pp.370-379. HARCOURT-BROWN, F. 120021 Dental disease. In: Textbook of rabbit medicine. Butterworth- Heinemann, Oxford, pp. 165-205.

HOBSON, P. (2006) Dentistry. In: Meredith, A.. Flecknell, P. Eds. BSAVA Manual of Rabbit Medicine and Surgery. 2nd ed. British Small Animal Veterinary Association Gloucester pp.184-196.

• VOL 27 • January 2012 • Veterinary Nursing Journal