What vets should know about rabbit behaviour and needs

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1 Vet Times The website for the veterinary profession What vets should know about rabbit behaviour and needs Author : ELISABETTA MANCINELLI, WENDY BAMENT Categories : Vets Date : May 26, 2014 ELISABETTA MANCINELLI DVM, CertZooMed, DipECZM (small mammal), MRCVS WENDY BAMENT RVN, MSc, BSc(Hons), CertVN(Exotics) exotic encounters RABBITS are common household pets in the UK and now the third most popular mammalian pet, after dogs and cats, with an estimated population of two million (MSD Animal Health, industry estimates, 2011). Rabbits are often bought as pets for children due to their low cost, size and perceived ease of care. The role of a veterinarian is to recognise the special needs of these patients and their owners; and to encourage responsible management, husbandry and breeding practices, thereby promoting health care and welfare for these animals. This can only be achieved by correct and extensive communication, which will eventually improve general perception and understanding. Natural behaviour and housing needs Pet rabbits descend from the European wild rabbit (Oryctolagus cuniculus) and, despite decades of domestication, they still show a range of behaviour that differs very little from their wild counterpart (Lehmann, 1991; Stoddart and Myers, 1964). Therefore, it can be assumed they are likely to have the same needs. The fact pet rabbits have been traditionally sold as children s pets, housed in hutches and fed a 1 / 20

2 concentrated diet, implies their condition has been altered radically compared to their wild ancestors and raises welfare issues related to the husbandry and environmental conditions in which they are commonly kept (Mullan and Main, 2006). The Animal Welfare Act 2006 ( ) makes owners and keepers responsible for ensuring the welfare needs of their animal are met. These include the need for a suitable environment, a suitable diet, the opportunity to exhibit natural and normal behaviour, the need to be housed with or apart from other animals (depending on the species) and the need to be protected from pain, suffering, diseases and injuries. This means not only is it cruel, but it is also against legislation if all the animal s welfare needs are not met. Wild rabbits are very social. They live in colonies in which many individuals (from pairs to 20 or more) share a wide home range of around 7,000 sq m to 20,000 sq m (Devillards et al, 2008; Lehmann, 1991). Much of their time is spent underground, but when out of their burrows rabbits can spend 40 per cent to 50 per cent of their time in contact with other individuals (Nelissen, 1975; Cowan, 1987). Domestic rabbits are often kept as single pets (44 per cent) and 84 per cent of them are housed in a hutch smaller than the minimum size (6ft 2ft 2ft or 0.68m3) recommended by the Rabbit Welfare Association and Fund (RWAF) and the PDSA (RWAF; PDSA, 2012; Mullan and Main, 2006). Rabbits are a highly intelligent, social and inquisitive species that would greatly benefit from the presence of a companion to be able to fully express their repertoire of behaviours (Figure 1). Providing environmental and behavioural enrichment could therefore enhance their welfare. A survey was undertaken to determine the knowledge and attitude of pet rabbit owners at the time of purchase and to investigate factors that would influence the husbandry and housing owners were planning to provide. Only 40 per cent of potential owners were planning to include hay or grass in their rabbit s diet, 29 per cent opted for a mix-type diet and 46 per cent unspecified concentrated food (Edgar and Mullan, 2006). Many owners are unaware rabbits are strict herbivores and that indigestible fibre is essential as it stimulates the motility of their gastrointestinal (GI) tract, has a protective effect against enteritis, relieves boredom and also provides dental wear (Figure 2). A diet providing 12 per cent to 16 per cent protein, 20 per cent to 25 per cent fibre, and 2.5 per cent to four per cent fat is considered appropriate for pet rabbits (Campbell-Ward, 2012). Veterinary care Many conditions that can compromise rabbit welfare and are commonly seen in private practice (such as dental disease, GI issues, perineal soiling and obesity), could easily be prevented because they are often the result of poor husbandry and management. 2 / 20

3 Furthermore, selective and indiscriminate breeding has created more than 100 recognised breeds, although many pet rabbits are the result of hybrid breeding. This has resulted in severe extremes and worsening of certain health conditions. True dwarf rabbits often have abnormal skull proportions and/or abnormal anatomical relationships between the mandible and the maxilla, and are more prone to develop congenital dental abnormalities (Figure 3). Lop-eared rabbits have a physiologically narrower ear canal and develop ear problems more commonly compared to other rabbit breeds (Capello, 2004). No generally accepted objective criteria for pain assessment in rabbits exist; however, Leach et al (2011) and Keating et al (2012) introduced a behaviour-based pain scoring system (rabbit grimace scale) where changes in facial expression and body posture may be useful indicators of acute pain in this prey species. Heart rate, respiratory rate and blood pressure are useful physiologic parameters that can be altered in case of pain. However, a variety of other factors including drugs, diseases, stress, anxiety and even restraint can induce changes in these variables, thereby limiting their specificity in pain assessment (Barter, 2011). Pain should be treated from an ethical, welfare and medical perspective. Poor pain management is known to delay postoperative recovery and wound healing. Digestive system Rabbits are hindgut fermenting monogastric herbivores, adapted for efficient digestion of fibrous food. They have a simple stomach, a well-developed caecum (10 times the capacity of the stomach) and a proximal colon, whereby a particle-dependent separation mechanism leads to production of two different types of faecal pellets (Figures 4 and 5). Indigestible fibres are expelled immediately to form hard faecal pellets, whereas digestible fibres are retropulsed into the caecum for further microbial fermentation and production of soft faecal pellets or caecotrophs, which are then reingested, contributing to the rabbit s digestive efficiency (Figure 6). Rabbits feed approximately 30 times per day, 2g to 8g of food per time, over a four to six-minute period and they have a low gut retention time of approximately 17 to 19 hours ( Johnson-Delaney, 2006; Campbell-Ward, 2012). Poor nutrition can disrupt these mechanisms, compromising the rabbits gastrointestinal and behavioural health. The term rabbit gastrointestinal syndrome (RGIS) has been introduced to define a complex of clinical signs, symptoms and concurrent pathologic conditions affecting the GI tract of rabbits (Table 1), often without an identifiable primary underlying cause (Lichtenberger and Lennox, 2010). In this review, the authors summarise the diagnostic and possible therapeutic approaches when presented with a rabbit suffering from a GI problem. Respiratory system Respiratory disease, caused by either primary or secondary causes, is common in pet rabbits. Rabbits are obligate nasal breathers and opened mouth breathing always produces a poor 3 / 20

4 prognosis. There are no connective tissue septa dividing the pulmonary tissue into lobules. This feature has significant implications in presence of pathology of the lower respiratory tract as pneumonia in rabbits is always generalised and it can, therefore, be haematogenous or bronchogenic in origin (Vella and Donnelly, 2012). Reproductive system Female rabbits lack a uterine body and have instead two uterine horns that open separately into the vagina. The two cervices need to be removed during routine neutering, therefore the procedure is actually an ovariohyster-ovaginectomy as the incision is made through the vagina (Vella and Donnelly, 2012). The urethra opens midway along of the long and flaccid vagina and this has multiple implications. Firstly, it is important to avoid expressing the bladder before elective neutering as urine can pool into the vagina and potentially contaminate the abdominal cavity when the utero-cervical tissue is transected. Secondly, haematuria does not allow differentiation between haemorrhage originating from the reproductive or urinary tract. Disorders of the reproductive tract in female rabbits are seen less commonly where educated owners elect to have their rabbits spayed to prevent the otherwise common uterine diseases. Nervous system Encephalitozoon cuniculi is an obligate, intracellular, spore-forming microsporidian parasite well documented in rabbits as responsible for latent infections and overt clinical neurological signs after stress and/or diseases causing immune-suppression. Fifty-two per cent of healthy domestic rabbits have been found to be serologically positive with antibodies against E cuniculi in the UK (Keeble and Shaw, 2006). E cuniculi is a zoonotic agent and infections have been reported in immunocompromised individuals, such as AIDS patients or organ transplant recipients (Deplazes et al, 1996). Nutritional and fluid therapy Optimal water supply is extremely important in rabbits as they can easily get dehydrated. Different drinking systems are available, but a study has demonstrated rabbits when given the option, prefer drinking from open dishes and that open dishes allow a faster water intake (Tschudin et al, 2011; Figure 7 ). Anorexia can rapidly lead to fatal hepatic lipidosis, therefore enteral support is essential in ill rabbits with a negative energy balance. Several commercial products are available for syringe feeding including Oxbow Critical Care (Oxbow Pet Product), a timothy hay-based syringe feeding formula that provides 2.69 kcal per gram of dry weight of the powder, and Recovery Plus formula (Supreme Pet Foods; Figure 8). 4 / 20

5 When syringe feeding is refused or contraindicated, a nasogastric tube placement can be considered (Figure 9). Two diets have been designed for use with these tubes: Emeraid Herbivore Elemental diet (Lafeber) and Oxbow Fine Grind Critical Care (Oxbow Pet Products; Lichtenberger and Lennox, 2010). Fluid therapy always plays an important role. Rehydration (based on estimated percentage of dehydration) and maintenance fluid (100ml/ kg/day) are provided till perfusion parameters are normal and the rabbit is eating and drinking normally (Lichtenberger and Lennox, 2010). Before enteral therapy is started the GI tract must be adequately hydrated to aid GI motility and function. Conclusions Rabbits are very social animals. They need mental stimulation and to express their normal behaviours, but they also need and benefit from interaction with their owners. Rabbits experience pain and thus we are ethically obliged to provide relief from pain arising from trauma, surgery or diseases. As veterinarians we are one of the main resources of information for pet rabbit owners, but clear guidelines to help in an educated choice need to be put in place. Improvements in a rabbit s welfare and health will only come from education, acknowledging the specific requirements of this typically misunderstood pet. References and further reading Barter L S (2011). Rabbit analgesia, Vet Clin Exot Anim 14(1): Capello V (2004). Surgical treatment of otitis externa and media in pet rabbits, Exotic DVM 6(3): Campbell-Ward M L (2012). Gastrointestinal physiology and nutrition. In Quesenberry K E and Carpenter J W (eds), Ferrets, Rabbits, and Rodents Clinical Medicine and Surgery (3rd edn), Elsevier Saunders, St Louis, Missouri 14: Cowan D P (1987). Group living in the European rabbit (Oryctolagus cuniculus): mutual benefit or resource localisation? J Anim Ecol 56(3): Deplazes P, Mathis A, Baumgartner R et al (1996). Immunologic and molecular characteristics of Encephalitozoon-like microsporidia isolated from humans and rabbits indicate that Encephalitozoon cuniculi is a zoonotic parasite, Clin Infect Dis 22(3): Devillards S, Aubineau J, Berger F et al (2008). Home range of the European rabbit (Oryctolagus cuniculus) in three contrasting French populations, Mammal Biol 73(2): Edgar J L and Mullan S M (2011). Knowledge and attitudes of 52 UK pet rabbit owners at the point of sale, Vet Rec 168(13): 353. Johnson-Delaney C A (2006). Anatomy and physiology of the rabbit and rodent gastrointestinal system, AEMV 2006 Proceedings: / 20

6 Keating S C J, Thomas A A, Flecknell P et al (2012). Evaluation of EMLA cream for preventing pain during tattooing of rabbits: changes in physiological, behavioural and facial expression responses, PLoS ONE 7(9): e doi: /journal. pone Keeble E J and Shaw D J (2006). Seroprevalence of antibodies to Encephalitozoon cuniculi in domestic rabbits in the United Kingdom, Vet Rec 158(16): Leach M C, Coulter C A, Richardson C A et at (2011). Are we looking in the wrong place? Implications for behavioural based pain assessment in rabbits (Oryctolagus cuniculus) and beyond, PLoS ONE 6(3), e doi: /journal.pone Lehmann M (1991). Social behaviour in young domestic rabbits under semi-natural conditions, Appl Anim Behav Sci 32(2): Lichtenberger M and Lennox A (2010). Updates and advanced therapies for gastrointestinal stasis in rabbits, Vet Clin Exot Anim 13(3): Mullan S M and Main D C (2006). Survey of the husbandry, health and welfare of 102 pet rabbits, Vet Rec 159(4): Nelissen M (1975). On the diurnal rhythm of activity of Oryctolagus cuniculus, Acta Zoologica et Pathologica Antverpiensia 61: PDSA. Rabbits: a suitable environment, Accessed March 9, RWAF. ahutchisnotenough.htm Accessed March 9, Stoddart E and Myers K (1964). A comparison of behaviour, reproduction and mortality of wild and domestic rabbits in confined populations, CSIRO Wildlife Research 9: Tschudin A, Clauss M, Codron D et al (2011). Preference of rabbits for drinking from open dishes versus nipple drinkers, Vet Rec 168(7): 190. Vella D and Donnelly T M (2012). Basic anatomy, physiology, and husbandry. In Quesenberry K E and Carpenter J W (eds), Ferrets, Rabbits, and Rodents Clinical Medicine and Surgery (3rd edn), Elsevier Saunders, St Louis, Missouri: / 20

7 Figure 1. Rabbits are highly intelligent, social and inquisitive and would greatly benefit from the presence of a companion to be able to fully express their repertoire of behaviours. 7 / 20

8 Figure 2. Rabbits are strict herbivores and hindgut fermenters. Indigestible fibre is essential as it stimulates the motility of their gastrointestinal tract, has a protective effect against enteritis, relieves boredom and provides dental wear. 8 / 20

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10 Figure 3. Breed selection, especially in true dwarf rabbits, often leads to an abnormal anatomical relationship between the maxilla and the mandible. Mandibular prognatism and maxillary brachygnathism are commonly seen. 10 / 20

11 Figure 4. The rabbit s gastrointestinal tract (GI) contains up to 10 per cent to 20 per cent of the animal s bodyweight and 80 per cent of the digesta. The stomach and caecum contents represent five per cent to 19 per cent (average 10 per cent) of the rabbit s total bodyweight. The small intestine contains 12 per cent of the total volume of the GI tract. 11 / 20

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13 Figure 5. Rabbits have a large caecum that holds 40 per cent of the ingesta, has a semiliquid content and contains large numbers of microorganisms (mainly anaerobic GRAM-genus Bacteroides), which produce volatile fatty acids (VFAs), thus providing approx 40 per cent of the rabbit s basal energy requirement when VFAs are absorbed directly across the caecal mucosa or reingested in caecotrophs. Figure 6. From left to right, shows caecotrophs and normal faecal pellets from a healthy domestic rabbit and hard, dry faecal pellets from a rabbit with altered faecal output. 13 / 20

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16 Figure 7. Rabbits, when given the option, prefer drinking from open dishes and these also allow a faster water intake. 16 / 20

17 Figure 8. A timothy hay-based feeding formula mixed with water can be fed through a syringe. Most anorexic rabbits will accept this. 17 / 20

18 Figure 9. When syringe feeding is refused or contraindicated, a nasogastric tube placement can be considered. 18 / 20

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20 Table 1. Common pathologic conditions observed in the gastrointestinal tract of pet rabbits (RGIS; Lichtenberger and Lennox, 2010). 20 / 20 Powered by TCPDF (