Rabbit Medicine Flashcards
What is the gait of a normal rabbit like?
The forelimb has five digits and the hind limb has four, the gait is plantigrade at rest and digitigrade when running.
What is the formula for the vertebral column of a rabbit?
The vertebral formula is C7,T12, L7,S4, C15-C16
What is the dental formula for a rabbit
2/1 0/0 3/2 3/3. The vestigial second pair of upper incisors are located directly behind the first pair and are known as peg teeth. All teeth are open rooted, long crowned (aradicular hyspodont) and grow continuously. The term cheek teeth refers to both the premolars and molars. they are wider apart on the maxilla than the mandible. Mandibular cheek teeth grow faster than maxillary. The oral commissure is small and the oral cavity long and curved. cheek folds across the diastema make visualisation difficult in conscious animal.
When does a rabbits coat come through?
The guard hairs are the first to emerge in new born kits, followed by the undercoat. By a few days this soft baby coat is well developed and it persists untill about five or six weeks of age, an intermediate or pre adult coat then replaces this followed by the adult coat by about six to 8 months of age. Most rabbits moult twice a year but this can vary.
When may a rabbit loose hair?
Pregnant or pseudo pregnant does undergo a loosening of the hairs on the belly, thighs, chest - which are then plucked to line the nest and expose nipples.
What is the dewlap?
Female rabbits possess a large fold of skin under the chin known as the dewlap
Where are scent glands located in rabbits?
Underside of the chin on either side of the perineum of both sexes and at the anus. The inguinal glands (either side of perineum) are large and pouch like and often contain a yellow brown oily deposit.
Describe the structures of the rabbit eye
The lensi s large and almost spherical. the retina is merangiotic with the optic disc lying above the midline of the eye and retinal vessels spreading horizontally out from it. the optic disc has a natural depression or cup. there is no tapetum lucidum. a third eyelid is present and the harderian gland is located just behind it. rabbits only blink 10-12 times per hour and so are prone to corneal ulceration and drying of the corneal surface. A network of blood vessels is located immediately behind the eye including the post orbital venous sinus which must be avoided during enucleation surgery. the nasolacrimal duct has a single lacrimal punctum in the medial aspect of the lower eyelid. the duct has two sharp bends as it courses towards the nose, proximally in the maxillary bone and at the base of the incisor teeth. The duct narrows at these points and is therefore very prone to blockage.
Describe the stomach of the rabbit?
The stomach is large and J shaped and located to the left of midline in the cranial abdomen. there is a well developed cardiac sphincter which prevents vomiting. The PH varies diurnally but can be as low as 1-2. the stomach usually contains hair, food and fluid even after 24 hours of fasting/anorexia
Describe the small intestine of a rabbit
Primary site of nutrient absorption. the bile duct and a separate single pancreatic duct open into the duodenum. the terminal ileum enlarges into a dilation known as the sacculus rotundus at the ileocaecocolic junction. the sacculus rotundus is unique to the rabbit and is composed of lymphoid tissue. Retrograde movement of the ingesta from the large intestine back into the ileum is inhibited by a valve type mechanism.
Describe the large intestine of the rabbit?
Highly developed in the rabbit. the caecum is the largest organ in the abdominal cavity and it functions as a fermentation vat. it is very thin walled and coiled and ends in the blind ended vermiform appendix. the caecal contents are semi fluid. the colon is functionaly divided into 2 parts; the proximal colon which features grossly distinct haustrae and taenia and the distal part which is unhaustrated. the proximal colon is the site of separation of particles into digestible fraction which settles near the mucosa and is propelled in a retrograde fashion back into the caecum via coordinated contractions and The indigestible fraction which is passed in the centre of the lumen through to the distal colon for expulsion as hard faecal pellets. Normal function relies on a highly coordinated pattern of intestinal motility which in itself is promoted by indigestible dietary fibre. At the junction between the proximal and distal colon is the fusus coli, an area of thickened circular muscle which acts as the intestinal pacemaker, controlling colonic motility and also where ingesta is formed into distinct pellets. To facilitate the breakdown of the digestible fraction, teh caecum and the colon of the rabbit have a well established indigenous population of microorganisms. these microorganisms produce the volatile fatty acids acetate, butyrate and propionate which provide up to 40% of the maintenance energy requirement of the rabbit. the products of fermentation may be absorbed directly through the caecal wall and are also expelled and reingested as caecotrophs. The strict anaerobes bacteroides are the predominant organisms but also many others. coliform bacteria and clostridium present in very small numbers, if at all.
What is caecotrophy in the rabbit?
Rabbits produce two types of faeces, hard faeces and caecotrophs (also termed night faeces) which differ markedly in composition. caecotrophy is the ingestion of small packets of caecal contents - which improves feed utilisation by maximising the absorption of nutrients and bacterial fermentation products (amino acids, volatile fatty acids and vitamins B and K) In the normal rabbit caecotrophs and hard faeces are not excreted at the same time. Caecotrophs are covered by a mucous envelope and secreted in the proximal colon and are passed as pellets of approximately 5mm diameter arranged in clusters. Arrival of such clusters at the anus triggers a reflex licking of the area and ingestion of the caecotrophs which are swallowed whole. Following consumption caecotrophs remain in the stomach of the rabbit for 6-8 hours. they are preserved in an intact state due to their protective mucous coating allowing the microorganisms within them to continue the fermentation process
Describe the pancreas/liver of the rabbit
The pancreas is diffuse and located in a pocket formed by the transverse colon, stomach and duodenum. a gall bladder is present and rabbits secrete mainly biliverdin in the bile rather than bilirubin. the liver has four lobes. overweight rabbits will often have significant lipid stores in the liver which predisposes them to hepatic lipidosis if they undergo periods of fasting or anorexia.
Describe the immune system structures of the rabbit
The spleen is small, flat and elongated and lies on the dorsolateral surface of the greater curvature of the stomach. the thymus gland is present in the adult rabbit and is located cranial to the heart. a significant proportion of the rabbits lymphoid tissue is present as gut associated lymphoid tissue (GALT). this includes tissue present in the tonsils, sacculus rotundus, appendix and small intestinal peyers patches.
Describe the respiratory system of the rabbit
rabbits are obligate nasal breathers and as a result upper respiratory exudates or obstructions as well as damage to teh nares or turbinates can be very serious. the nose moves up and down in a normal rabbit twitching 20-120 times a minute but this will stop when the rabbit is very relaxed or anaesthetised. The glottis is small and visually obscure by the back of the tongue.
How does the urinary system of the rabbit differ from other animals?
Calcium absorption from the gastrointestinal tract usually occurs independent of vitamin D. urine is the major route of excretion for excess calcium that has been absorbed and as such calcium crystalluria is a common normal finding. Porphyrinuria is also common in normal rabbits and in general this species has a high fluid intake.
Describe the reproductive tract of the doe
Does have no uterine body, two separate uterine horns and two cervices opening into the vagina. the vagina is large and flaccid. The mesometrium is a major site of fat deposition. the placenta is hamochorial.
When is the onset of puberty in rabbits
approx 4-5 months in the female and 5-8 months in the male. Smaller breeds mature earlier than larger ones. Does tend to be more territoril than bucks and the dose should be taken to the buck or neutral territory for breeding, to avoid aggression.
What is the oestrus cycle of the doe?
Rabbits are reflux ovulators, there is no definitie oestrus cycle. receptive periods occur usually 12-14 days folowed by 2-4 days of non receptivity. Some does become receptive every 4-6 days during the breeding season. Sexually mature bucks will mate at any time. The vulva becomes congested and reddish purple when receptive.
When can pregnancy be detected?
by palpation at 14 days, gestation approx 30-34 days. NEst building behaviour involes burrowing and pulling of fur from dewlap, flanks and belly to line nest. parturition usually occurs in the early morning and the kits are altricial.
What is the normal HR of a rabbit?
180-300 per min
what is the normal resp rate of a rabbit?
30-60 per min
What is the normal body temperature of a rabbit ?
38.5-40C
Where can a pulse rate be taken from?
Via the femoral canal or central auricular artery
How does dehydration appear in the rabbit? where can this be assessed?
Dehydration results in sunken eyes and a loss of skin elasticity. the most useful areas of skin to assess hydration status are in the relatively hairless inguinal region, on the inside of the pinnae and in males, the scrotal skin. Rapid alterations in body weight may also provide some indication as to the degree of dehydration.
Describe how to examine the integument of the rabbit?
An initial assessment of coat quality is made during visual inspection. This is folowed by a systematic inspection of the entire surface, fur should be soft, dense, clean dry and free of matts. the underlying skin is inspected by brushing the coat in the direction opposing hair growth or in long haired breeds by parting the pelage. Areas frequently associated with dermatoses in rabbits that should be inspected during any physical examination include the dorsum, the face, ventral neck, dewlap, perineum, palmar surfaces of the feet and hocks. examination of some of these key areas will require suitable restraint of the rabbit with its ventrum exposed. Note areas of erythema, bruising, ulceration, crusting, scaling, wetness (especially ventral neck, medial forelimbs or the perineum, malodour and discolouration of the fur or skin. urine scald or an accumulation of soft faeces in the perineal region is always significant. myiasis (fly strike) should be considered an emergency.
Describe how to examine the respiratory system of the rabbit
Respiratory rate and rhythmn are assessed prior to handling. the nares are examined and should be equally patent and free of any discharge. if discharge is present, its nature should be noted eg unilateral and mucopurulent. if the rabbit is sneezing or dyspnoeic note the severity and pattern of the clinical signs. Auscultate both sides of the chest and over the trachea. the use of an infant or paediatric stethoscope is recommended, particularly in dwarf breeds or juveniles. in the normal rabbit, short regular and rapid inspiratory sounds are heard in all lung fields. abnormalities that should be noted may include wheezes, crackles or an absence of sounds. location and timing of abnormal noises should be recorded.
How can the cardiovascular system be assessed in a rabbit
Mucous membrane colour is assessed by inspection or oral or conjunctival mucosa. the normal colour is light pink, slightly paler than in a normal dog or cat. To improve efficiency and minimise handling this can be combined with the oral and or opthalmic components o the examination.n. Capillary refill time is assessed on the gingival mucous membranes. Auscultate the heart to assess heart rate and rhythm. check pulse rate and quality.
How can the gastrointestinal system of the rabbit be assessed?
mouth - rabbit positioned in dorsal/sternal recumbency, part upper lips at philtrum. Cheek teth and tongue are examined with aid of an otoscope with a large plastic or metal cone attached. abnormalities that may be visualised include crown elongation, malocclusion, spike formation, tooth loss, infection, soft tissue trauma and haemorrhage. Absence of clinical findings on a limited oral examination does not exclude the possibility of dental or oral disease. Sedation or generaly anaesthesia is necessary. Face should be palpated along maxillae, zygomatic arches and ventral mandible. Irregularities, assymetries, swellings or painful foci should be noted.
How should the urogenital system be examined in a rabbit?
The kidneys are palpable, unless there is a large amount of retroperitoneal and abdominal fat present. they are mobile and located slightly more cranially tan those of dogs and cats. the bladder is usually palpable in the caudal abdomen. it should be handled carefully as it is very thin walled. Gender is confirmed by examination of the external genitalia. for the male - examine the scrotum and penis. the testis should be smooth, symmetrical and non painful but may in the normal be partially retracted into the abdomen. Examine the female vulva and note any discharge or inflammation. if entire and non pregnant the uterus and ovaries are often not palpable per abdomen. Pregnancy can be detected by palpation from day 12 of gestation.
How should the eyes of the rabbit be examined?
Evidence of occular discharge should be noted including wetness, alopecia or crusting of the periocular skin. The nature of any discharge and whether it is unilateral or bilateral should be recorded. Observe for aberrations in eye position. Nystagmus, exopthalmos or a sunken posiitioon of one or both eyes are significant findings. The opening to the lacrimal duct is examined by gently lifting the lower eyelid away from the globe near the medial canthus. At the same time gentle pressure is applied to the face ventromedial to the eye to observe for discharge from the punctum. The eyelids are examined for symmetry, oedema, irregularities or swellings along the margins, aberrant eyelashes, entropion or ectropion. the cornea should be cear. The exact location and nature of any corneal lesion should be noted. The conjunctiva, sclera, nictitating membrane, anterior chamber, iris and lens of both eyes are examined in turn and any abnormalities described.
Which lymph nodes can be palpated in the rabbit?
The popliteal and prescapular lymph nodes can be normally palpated. Other lymph nodes (auxillar, inguinal, submanibular) are only palpable when enlarged. Local or generalised enlargement may be associated with disease or injury.
How does congenital malocclusion present in a rabbit?
Congenital malocclusion first presents at 8-10 weeks of age. Breed predispositions oof mandibular prognathism/maxillary brachygnathism include some dwarf and op eared breeds. primary incisor malocclusion and elongation cannot be corrected - the mandibular incisors become straighter due to lack of occlusion and maxillary incisors form spiral curvatures and may penetrate the palate or cheek if left untreated.
Hw doe acquired malocclusion/dental disease present in rabbits?
Seen mainly in adults. Inadequate dental wear/ attrition is a common cause where rabbits are fed a high carbohydrate low fibre diet resulting in elongation of the entire tooth (exposed crown and reserve crown), increased length and curvature of the cheek teeth result in spike formation of the lingual occlusal surface of the mandibular teeth and the buccal occlusal surface of the m axillary teeth. Lateral mandibular movement is also restricted. this elongation of the cheek teeth prevents normal occlusion and therefoore dental wear of the incisors resulting in secondary incisor maloocclusion. calcium deficiency or calcium:phsphorus imbalancs due to selective feeding when offered excessive quantities of coarse mix food can lead to alveolar bone resorptioon and tooth elongation and curvature leads to spaces opening up between teeth, periodontal pocket formation, infection and eventually abscessation. Traumatic injury including mandibular symphysis separation, temperomandibular joint subluxation, mandibular ramus fractures, tooth fractures with subsequent pulp exposure and tooth root abscess formation are also commonly seen.
What are the clinical signs of dental disease in rabbits?
Anorex,a dysphagia, bruxism due to pain, ptyalism with secondary moist dermatitis, halitosis, epiphora, weight loss, reduction in size or amount of faecal pellets, decreased grooming, reduction or inability of ingestion of caecotorphs, abscesses or facial swelling development may all be signs of dental disease. Lateral jaw movement will be restricted ad may be painful if spikes are present. Pyrexia is not usually seen with abscesses in rabbits. root elongation of the mandibular cheek teeth results in palpable distortion of the normal smooth ventral border of the mandible. Root elongation of the maxillary cheek teeth impinges on the orbit and may prevent globe retraction or case proptosis as a sequel to retrobulbar abscess formation.
How is diagnosis of dental disease made in rabbits?
Usually suspected on clinical signs and history. conscious oral examination may reveal some dental and soft tissue changes (tongue and upper buccal mucosa lacerations from spurs/spikes are common sites, but radiography is essential to evaluate the disease of the roots and surrounding alveolar bone. Radiolucent Periapical regions due to bone lysis and abscess formation and periosteal bone reaction may be identified on radiography.
What is the treatment and prognosis for dental disease in rabbits?
Dependeing on the primary cause of dental disease, corrective burring or extractio of affected teeth, supportive care ad diet change to higher fibre diet may be indicated. burring of incisors can be performed conscious using either high or low speed dental equipment. buring of cheek teeth requires general anaesthesia, specialist mouth gags and cheek dilators. clipping and rasping are unacceptable because the former results in tooth fracture and rasping can damage the periodontal ligament. cheek teeth must be burred down to the correct level for normal occlusion and lateral movement and thus spikes iwll also be removed. repeated treatments and long term management are needed as restoration of normal dentition s very rarely achievable. indications for incisor extraction include malocclusion root infection and loss of opposing tooth. Coomplete surgical excision is the recommended treatment of abscesses in the rabbit, followed by marsupialisation or closure after placement of an antibiotic impregnated impplant. Prognosis of dental disease is dependent on the primary cause and extent of secondary changes. If there is radiographic evidence of osteomyelitis the prognosis is guarded to poor.
What is gastric stasis and gastrointestinal ileus in the rabbit?
Gastric stasis is primarily an acquired disorder of decreased motility. generalised ileus is a common continuation of this condition and may arise from mechanical obstruction or from defective propulsion. Mechanical obstructions eg dehydrated impacted ingesta secondary to chronic dehydration, foreign bodies, infiltrative lesions, cause delayed gastric emptying. Abnormalities in myenteric neuronal or gastric smooth muscle function or contractility result in defective propulsion. Primary factors associated with these functional disorders include anorexia, high carbohydrate/low fibre diet, post surgical adhesions, lack oof excercise toxin ingestion, secondary factrs include pain and enviroonmental stressors such as proximity of predators or a dominant rabbit, change in group hierarchy, loss of a companion, change in housing routine or diet, transport, extremes of temperature or humidity. Anorexia and chronic dehydration are both causal factors and consequences of gastric stasis and ileus. Systemic dehydration leads to gut content dehydration and impaction of normal stomach contents which includes loose hair lattices or trichbezoars.
What are the clinical signs of gastric stasis and gastrointestinal ileus?
Gradual decrease in appetite leading to anorexia (days-weeks), decreased size and amount of faecal pellets, gradual progression from bright and alert to depression, dehydration and death. If obstructive ileus - may initially appear bright, but rapidly becomes depressed, acute anorexia and acute history of no faeces.
How is diagnosis of gastrointestinal ileus made?
The history and clinical findings of a firm dough like stomach on palpatioon, allow a presumptive diagnosis o gastric stasis and ileus and are suggestive of non obstructive disease. Although, advanced cases do not permit differentiation between obstructive and non obstructive. Radiography in early cases reveals a mass of hair and food appearing similar to normal digesta. as impaction in the stomach and occasionally caecum develops, a gas halo is often seen around the compacted material. Large amounts of gas are seen throghout the gastrointestinal tract as a result of ileus. A definitive diagnosis can only be made on exploratory laparotomy however this is a high risk prcedure in these already unstable rabbits.
What is the treatment and prognosis for gastrointestinal ileus?
Aggressive medical management is required to prevent further deterioration and death. nearly 10% of fundic ulcers found to be associated with anorexia or caecal impaction. Nutritional support is essential, hepatic lipidosis is a common coomplication and cause of death in rabbits. rehydration of both the patient and stomach contents with both oral and IV fluids may be required depending on the severity of the case. Analgesics such as bupreorphine, butrphanol, morphine or pethidine should be used in the first instance then once rehydrated, NSAIDs eg meloxicam. Prokinetics are required to stimulate GIT motility. Metoclopramide or domperidone are dopamine antagonists having both central and peripheral effects. the prokinetic effects of metooclopramide are not as potent as cisapride and are limited to the proximal GIT. having a prokinetic effects equal to cisapride and antacid actions makes ranitidine a very useful drug. Rehydration is essential, likely to be more beneficial than liquid paraffin, papain enzyme, pineapple juice and bromelin which have no proven efficacy. Simethicone or dimethicone are NOT indicated for dispersing gastric gas due to tight cardiac sphincter.
What is myxomatosis in the rabbit? what are the clinical signs?
Caused by myxoma virus. Usually fatal disease of the european rabbit. wild outbreaks wax and wane according to the strain virulence & immune status of native population. Virus persists in hutches, insect vectors include rabbit flea, mosquito, cheyletiella. skin lesions develop 4-5 days after inoculation, enlarge until 9-10 days after infection. eyelids become thickened. Closed completely by day 9 with semi purulent ocular discharge. Secondary lesions develop throughout the body typically nares lips base of ears external genitalia. If infection by inhalation - pneumonic signs are seen. disease more lethal at low temperatures. Good nursing and high temperature aid recovery. Grave prgnosis usually death. prevention by vaccine one dose from 5 weeks then annual booser.
What is rabbit haemorrhagic disease? what are the clinical signs?
Caused by a calicivirus. It is host specific and only affects european rabbits. rabbits less than 4 weeks have physiological immunity, remain unaffected and develop lifelong immunity. Susceptibility increases until 6-10 weeks of age. It is shed in urine, faeces and aerosol. Insect and bird vectors, fomites. Virus survives long time outside host. short icubation period of 3-4 days. Peracute cases cause sudden death. Acute cases - quiet pyrexic and increased respiratory rate - usually die within 12 hours. No specific treatment. Grave prognosis. Prevent with vaccine from 5 weeks and annual booster.
When should rabbits be neutered and why?
Neutering of all non breeding female rabbits at 4-6 months of age is strongly recommended to prevent uterine adenocarcinoma which Can affect 50-80% of intact does over 3yo. Male rabbits >4 months are also often neutered for behavioural reasons.
Should rabbits be routinely wormed?
Routine worming of pet rabbits is not necessary. Heavy burdens of oxyurids/pinworms may be sometimes seen and can be treated with fenbendazole. rabbits at risk of flystrike should be treated prophylatically with a fly repellant and insect growth inhibitor. In the UK, imidacloprid is licensed for the treatment of fleas. It is applied topically to the back of the neck. Environmental treatment and treatment of incontact animals is also required to control flea infestation.
What are URT signs in rabbits of respiratory disease?
Sneezing, snoring , dyspnoea, ocular discharge, conjunctivitis, dacryocytisis, nasal mucosa erosion and nasal discharge which may be seen matted on the medial distal aspect of the forelimbs. Auscultation of the trachea, sinuses and nares reveals rattles and rales.
What are the lower respiratory tract signs in a rabbit with respiratory disease?
Dyspnooea, cyanosis, anorexia, depression, pyrexia or hypothermia and lethargy. pulmonary rales or increased respiratory effort, particularly intercostal effort indicates LRT disease. Absence of lung sounds or very loud heart sounds may indicate replacement of normal lung tissue with consolidated lung tissue, abscesses or neoplasia. Friction sounds may be heard with pleuritis and fluid sounds are heard with pulmonary oedema. Bilateral exopthalmus is occasionally observed in rabbits with thymomas, related to interference of vascular return to the heart by the mass.
How is diagnosis of respiratory disease made in a rabbit?
Radiography, CT, rhinoscopy, bronchography, BAL, treatment: appropriate antibiosis, preferably after culture and sensitivity of nasal swabs or tracheal washes. suppoortive treatment is required in severe cases including oxygen tehrapy, nebulisation with mucolytics, bronchodilators, NSAIds and antibiotics. P multocida is usually sensitive to penicillin G, chloramphenicol, erythromycin, azithromycin, tetracyclines & fluorquinolones. Antibiotics which P multocida is knoown to have resistance to include lincomycin, clindamycin and some to streptomcyin & sulphonamides.
