The relationship between rabbits and man goes back over 3,000 years and they are used for food, fur, sport, research and as companion animals. Rabbits are increasing in popularity as pets, and in the UK are the third most popular mammalian pet after cats and dogs (Pet Food Manufacturer's Association 2002). Although traditionally a children's pet, rabbits are now more commonly kept by adults as a true companion animal in the home, taking the place of cats and dogs. There is a plethora of information sources for owners about companion rabbits, on the internet and in publications, and understanding of basic husbandry requirements has increased in recent years. Expectations for high quality veterinary care and the availability of pet insurance for rabbits in the UK, has lead to great improvements in medical and surgical care of many animals. However, there are still many welfare issues present, especially regarding diet and its effect on dental and gastrointestinal health, housing and behavioral problems. The number of unwanted companion rabbits rescued by welfare organisations is still high, with owners purchasing young animals on impulse, especially at Easter time, with scant regard to their requirements and the cost of veterinary care, or the behavioral changes that can occur at puberty if animals are not neutered.
The use of laboratory rabbits is generally decreasing and is low compared to the use of rodents. In 2002 the Home Office in the UK recorded 30,280 scientific procedures on rabbits, compared to over 2.2 million procedures on rats and mice (Home Office 2003). Strict legislation controls the welfare of laboratory rabbits in the UK and many other countries. The main welfare issues are that of housing and social requirements, the refinement of laboratory techniques such as anaesthesia and antibody production, and the assessment and alleviation of pain.
The update of this bibliography on Housing, Husbandry and Welfare of Rabbits reflects the enormous advances that have been made over the past decade in our knowledge and understanding of rabbit physiology and behavior, and will be an invaluable tool to veterinarians, researchers, animal technicians and all who work with this fascinating species. This introduction will largely reflect the author's opinion and experience of both companion and laboratory rabbits in the UK.
Housing
Rabbits are highly social animals with complex social behavior based largely on scent. Comparative studies of domesticated rabbits living in groups in large enclosures have shown they retain the full behavioral repertoire of their wild counterparts (Bell 1984). Housing for laboratory rabbits has generally improved greatly over the last decade, with group housing and environmental enrichment now the norm rather than the exception in many laboratories, and several guidelines on best practice for housing are available (Hubrecht 1999, 2000; Stauffacher 2000; Second Report of the BVAAWF/FRAME/RSPCA/UFAW Joint Working Group on Refinement). It is generally accepted that housing rabbits in pairs or groups, preferably in floor pens, can significantly improve their physical and psychological welfare. The welfare issues for singly housed rabbits are well known, and manifest mainly as stereotypic behavior, such as:
Permanently caged animals are also prone to osteoporosis due to inactivity (Claes and Burri 1979), and obesity. Rabbits housed in social groups benefit from both social interactions and exercise, and abnormal behaviors are greatly reduced (Love 1994; Batchelor 1995; Krohn 1999). Rabbits are commonly used for antisera production in laboratories and concerns that stress effects on both high and low-ranking group-housed rabbits may affect immune function have not been proven (Turner et al. 1997), leading to little justification for single housing for this purpose. In addition, health problems such as rhinitis and sinusitis (Asnuffles@) may be reduced, due to better ventilation and reduction in exposure to high ammonia concentrations (Love and Hammond 1991). Group housing can lead to problems such as aggression and stress if the group is unstable, and great care must be taken to ensure that groups are compatible. Intact males in particular are prone to fighting and there are differing opinions on the justification of using surgical neutering to manage this. However, from all the research to date, the benefits of group housing in terms of animal welfare far outweigh any disadvantages and should be used wherever possible. Furthermore, the improvements in physiological and psychological health should result in more physiologically normal experimental models, which may lead to a reduction in the numbers needed in research.
The sense of smell is very important to rabbits and complex information concerning social interactions relating to sex, hierarchy, and mother/infant relationships is communicated via this route (Bell 1986). For this reason the use of strong smelling substrates such as wood shavings should be avoided and partial rather than total cleaning out is preferable to retain a sense of security. Experiments have shown that that rabbits choose straw or shredded paper as a substrate in preference to wood shavings (Turner et al. 1992), and the strong smell of the latter may influence this preference.
Studies have also shown that environmental enrichment has great psychological benefits, especially for singly housed animals (Lidfors 1997). The provision of shelves or boxes to give an area of raised height seems to be particularly beneficial (Hansen 2000; Gerson 2000). The provision of hay has both behavioral (Berthelsen 1999) and health benefits (see below).
For companion rabbits, few guidelines exist, and inappropriate housing can still cause welfare issues, often due simply to owner ignorance or misinformation. The hutches sold in the majority of pet shops are far too small for rabbits to fulfil even basic behavioral requirements such as standing erect on the hind legs and the ability to hop. Rabbits should be kept with a companion wherever possible and allowed regular access to an exercise area. The ability to graze in an outdoor pen has benefits both in terms of exercise and dietary health. House rabbits generally benefit from more interaction with the owner than those kept in hutches, and are usually allowed to roam free in the house. However, chewing of household objects can lead to problems such as electrical burns from cables and gastrointestinal obstruction from ingestion of materials such as carpet. Therefore rabbits should not be left unsupervised and have a safe cage area for confinement when necessary.
Feeding
Feeding an appropriate diet to a companion rabbit is probably the single most important factor in maintaining its health. There is a great deal of literature relating to the nutrient requirements of production and laboratory rabbits, but relatively little relating specifically to the companion rabbit. Companion rabbits have the potential for a much longer life span than the short-lived production or experimental rabbit. Many of the diseases commonly seen in pet rabbits can be directly attributed to, or associated with, the feeding of an inappropriate diet and could be largely preventable.
Rabbits are adapted in terms of their teeth and digestive system to eat an herbaceous diet that is high in fiber, low in fat, and low in starchy carbohydrates. However, rabbits are commonly fed low fiber and high carbohydrate diets, which are linked to:
Neutering
Surgical neutering of laboratory rabbits is generally not undertaken, although it is used in some long-term situations to prevent aggression in group housed males. In companion rabbits, neutering is generally recommended. Unbred does are particularly prone to developing uterine adenocarcinoma, and the use of neutering as prevention is recommended. Neutering of both sexes will also prevent many behavioral problems such as territorial aggression and urine spraying that can result in animals becoming unwanted or sent to rescue organisations. The ethical arguments for and against the use of surgical intervention to prevent these problems divides opinion, but the welfare implications of an animal being neglected or abandoned must be borne in mind. It is generally recognised that a neutered female and a neutered male make the most stable social combination for companion rabbits.
Behavioral Problems
In both companion and laboratory rabbits individual housing, a barren environment and a concentrated, low fiber diet can lead to behavioral problems such as stereotypic behavior and aggression. Normal territorial behavior, especially in does on reaching sexual maturity, can manifest as cage guarding and biting when approached. Aggression can also be a learned behavior and a common cause is incorrect handling--the rabbit that is picked up in an insecure manner rapidly learns that if it bites the handler it will be put down. Pain is another important cause of aggression, especially in a previously tractable animal. Many behaviors seen as problems by the owner are in fact normal, such as digging, chewing and territorial marking with urine. Advice for behavioral problems is increasingly sought by rabbit owners from both veterinary surgeons and animal behavior counselors (McBride and Wickens 1997; Scott 2001).
Veterinary Care and Preventive Medicine
Many rabbit diseases are preventable (see Diet above) and a routine preventive medicine programme should be instituted to include dietary and husbandry advice, routine veterinary examination (Antinoff 1999) and, where appropriate, neutering and vaccination against Myxomatosis and Viral Haemorrhagic Disease. Outdoor rabbits are particularly prone to myiasis (flystrike) in summer months and should be checked regularly.
Anesthesia and Analgesia
Rabbits are particularly prone to stress on handling, and sedation or anaesthesia is frequently required for both minor and major veterinary or experimental procedures. Anaesthesia in rabbits is still judged as a relatively high risk procedure, with figures of up to 30% mortality reported (Kramer 1998). Provision of sedation or anaesthesia is an important welfare issue, but can in itself be a source of stress. In particular the use of volatile agents such as isoflurane, sevoflurane and desflurane for induction has been shown to be aversive and result in struggling and apnoea (Flecknell et al. 1999, Hedenqvist et al. 2001). Significant improvements in anaesthetic techniques have been made in the past decade or so, particularly the use of balanced anaesthetic regimes using a combination of agents in order to minimise unwanted side effects, such as medetomidine or xylazine, ketamine and butorphanol with supplementary oxygen (Borkowski and Zaras 1999; Meredith and Crossley 2000). Better peri-operative care, such as maintenance of body temperature, analgesia, fluid therapy, and gastrointestinal support plays a major role in decreasing anaesthetic complications and mortality.
References
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Bell, D.J. (1984). The behaviour of rabbits:implications for their laboratory management. In: Standards in Laboratory Animal Management 151-162. UFAW, Potters Bar, Herts, England.
Bell, D.J. (1986). Social effects on physiology in the European rabbit. Mammal Review 16: 131-137
Bennegadi, N.; Gidenne, T.; Licois, D. (2001). Impact of fibre deficiency and sanitary status on non-specific enteropathy of the growing rabbit. Animal Research 50(5): 401-413
Berthelsen, H. (1999). The effect of hay on the behaviour of caged rabbits (Oryctolagus cuniculus). Animal Welfare 8(2): 149-157
Borkowski, R.; Karas, A.Z. (1999). Sedation and anesthesia of pet rabbits. Clinical Techniques in Small Animal Practice 14(1): 44-49
Brown, S.A. (1997). Gastrointestinal physiology and disease in the domestic pet rabbit. In: The 21st Annual Waltham/OSU Symposium for the Treatment of Small Animal Diseases: Exotics, September 27-28, 1997
Claes L.; Burri C. (1979). Mechanical and histological findings in osteoporosis due to inactivity. Hefte Unfallheilkd 138: 297-302
Crossley, D.A. (2003). Oral biology and disorders of lagomorphs. Veterinary Clinics of North America: Exotic Animal Practice 6(3): 629-659.
Flecknell, P.A., Roughan, J.V., Hedenqvist, P. (1999). Induction of anaesthesia with sevoflurane and isoflurane in the rabbit. Laboratory Animals 33(1): 41-46
Gerson, P. (2000). The modification of "traditional" caging for experimental laboratory rabbits and assessment by behavioural study. Animal Technology: Journal of the Institute of Animal Technology 51(1): 13-36
Hansen, L.T.; Berthelsen, H. (2000). The effect of environmental enrichment on the behaviour of caged rabbits (Oryctolagus cuniculus). Applied Animal Behaviour Science 68(2): 163-178
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Home Office (2003). Statistics of Scientific Procedures on Living Animals in Great Britain 2002.
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