Rabbit Medicine Flashcards
(122 cards)
1
Q
What is the gait of a normal rabbit like?
A
The forelimb has five digits and the hind limb has four, the gait is plantigrade at rest and digitigrade when running.
2
Q
What is the formula for the vertebral column of a rabbit?
A
The vertebral formula is C7,T12, L7,S4, C15-C16
3
Q
What is the dental formula for a rabbit
A
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.
4
Q
When does a rabbits coat come through?
A
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.
5
Q
When may a rabbit loose hair?
A
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.
6
Q
What is the dewlap?
A
Female rabbits possess a large fold of skin under the chin known as the dewlap
7
Q
Where are scent glands located in rabbits?
A
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.
8
Q
Describe the structures of the rabbit eye
A
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.
9
Q
Describe the stomach of the rabbit?
A
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
10
Q
Describe the small intestine of a rabbit
A
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.
11
Q
Describe the large intestine of the rabbit?
A
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.
12
Q
What is caecotrophy in the rabbit?
A
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
13
Q
Describe the pancreas/liver of the rabbit
A
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.
14
Q
Describe the immune system structures of the rabbit
A
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.
15
Q
Describe the respiratory system of the rabbit
A
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.
16
Q
How does the urinary system of the rabbit differ from other animals?
A
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.
17
Q
Describe the reproductive tract of the doe
A
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.
18
Q
When is the onset of puberty in rabbits
A
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.
19
Q
What is the oestrus cycle of the doe?
A
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.
20
Q
When can pregnancy be detected?
A
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.
21
Q
What is the normal HR of a rabbit?
A
180-300 per min
22
Q
what is the normal resp rate of a rabbit?
A
30-60 per min
23
Q
What is the normal body temperature of a rabbit ?
A
38.5-40C
24
Q
Where can a pulse rate be taken from?
A
Via the femoral canal or central auricular artery
25
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.
26
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.
27
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.
28
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.
29
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.
30
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.
31
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.
32
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.
33
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.
34
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.
35
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.
36
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.
37
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.
38
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.
39
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.
40
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.
41
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.
42
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.
43
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.
44
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.
45
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.
46
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.
47
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.
48
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.
49
Describe pasteurella multocida as a respiratory pathogen in the rabbit?
It is a commensal organism of the mucous membranes that exhibits pathogenicity when the hosts immune defences are compromised. virulence factors of p multocida include adhesions, resistance to phagocytes, endo and exotoxins, iron regulation and production of filaments to assist binding to membranes. Causes Rhinitis including turbinate atrophy, snuffles and sinusitis.
50
What are the possible co pathogens to pasteurella in respiratory infections in the rabbit?
Bordetella bronchiseptica (causes damage to mucociliary escalator, staphylococcus aureus (co pathogen to P multocida),
51
How does cardiovascular disease present in a rabbit?
Signs suggestive of heart disease in rabbits include decreased appetite or complete anorexia, weight loss, dyspnoea, tahcypoea, hind limb weakness progressing to generalised weakness, exercise intolerance may be noted by some owners, especially in house rabbits, lethargy, syncope, collapse and sudden death.
52
What diagnostic tests should be done if you suspect a rabbit in heart failure?
Diagnostic investigation should include electrocardiography, radiography, echocardiography, blood pressure measurement. Blood pressure for rabbits is a mean arterial blood pressure 80-91mmHg or systolic 92-135 and diastolic 64-75. Normal values for ECG and echocardiographic parameters in pet rabbits have been reported.
53
What is the treatment of cardiovascular disease in rabbits?
There is no standard treatment of cardiovascular disease in the rabbit. However, a similar approach to the cat or dog is appropriate. Treatment should always be based on the clinical and functional classification of the disease process in the individual patient and where possible the underlying disease should be addressed, where this is not possible supportive management is required. Stabilisation may be required prior to detailed investigation and specific therapeutic intervention. Medication should start at low doses and low intervals, while closely monitoring for adverse effects. As vomiting is not seen in rabbits, anorexia or ileus may be the first general sign of an adverse reaction. Regular monitoring of clinica, radiogrpahic, serum electrolytes, creatinine and urea is essential to allow for adjustments in therapeutics as indicated.Over use of diuretics can rapidly lead to dehydration which in the rabbit may present as gastric or caecal impction.
54
What is the most common cause of scrusting and scaling of the skin in rabbits?
Crusting and scaling of the skin with mild pruritus especially along the dorsum is usually due to cheyletiella parasitovorax, the rabbit fur mite. it is a non burrowing mite, just visible to the naked eye. Many rabbits carry the mites with no overt signs. partial alopecia may be seen in heavy infestations. Cheyletiella is zoonotic, causing a papular dermatitis in peple. Diagnosis easily made with cellophane tape test. treatment of choice is ivermecitn. All in contacts should be treated and the environment thoroughly cleaned.
55
Describe otitis externa in the rabbit?
Characterised by pruritus and thick crusts on the inside of the pinnae often caused by psoroptes cunilculi, the rabbit ear mite. Lesions can spread to the face and neck and secondary bacterial infections can develop within the external ear canal. Mites can be visualised on otoscopic examination or by microscopic examination of aural debris. treatment with ivermectin or selamectin is usually effective.
56
What may cause ulcers and scabs of the nose or perineum?
Often due to the infection with spiroochaete treponema paraluis cuniculi also known as rabbit syphilis. Rabbits can be asymptomatic carriers with overt disease precipitated by stress. Definitive diagnosis involves microscopic visualisation of the organism from scrapes on a dark field background or with special silver stains on biopsy. it is often self limiting, but effective treatment can be achieved with injectable penicillin once every 7 days for 3 doses. All exposed rabbits should be treated. Not zoonotic.
57
What is plantar pododermatitis in the rabbit?
A common chronic ulcerative granulomatous dermatitis of the metatarsal area seen in overweight inactive rabbits kept on wet bedding or hard floors. Hereditary factors are also thought to be involved and rex rabbits are particularly affected as they lack protective guard hairs. secondary bacterial infection often occurs which can progress to osteomyelitis given the lack of soft tissue in the distal limb. Treatment involves addressing the initiating cause as well as debridement and cleaning of the lesions, topical and systemic antibiotic therapy and the application of dressings. Prevention involves providing more supportive bedding, increasing exercise and preventing obesity.
58
Why is perineal urine scald seen in rabbits?
May ooccur due to primary incontinence, poor husbandry eg urine soaked bedding, conditions that prevent normal positioning during urination (pododermatitis, obesity, arthritis, inadequate space), conditions that prevent normal grooming (dental disease, systemic illness), conditions that result in polyuria (chronic renal disease sludgy bladder sydrome) abnormal retention of calcium crystalluria. Treatment includes clipping and cleaning of the perineum, opioid and non steroidal analgesia and specific treatment of underlying disease.
59
What is encephalitozoonosis in rabbits?
Encephalitozoon cuniculi is a protozoal parasite which belongs to the phylum microsporidia. It is widespread in the domestic rabbit population. infection also in rodents and lots of others. Shed in the urine. In pet rabbits infection via ingestion of spores from urine contaminated food and water. Target organs are brain and kidney. The host cell eventually ruptures releasing spores into extracellular space and resulting in chronic inflammation and granuloma formation. Spores shed in urine for approx 9 weeks. Early infection confined to target organs such as lung,kidney liver affecting brain heart and kidney i more chronic infections. Clinical signs include head tilt, torticollis, hind limb paresis/paralysis, tremors, cnvulsions, urinary incontinence, cataracts and lens induced uveitis and death.
60
How is diagnosis of encephalitozoon cuniculi made?
IgG and IgM antibody assays are avilable in the UK and indicate exposure to the organism. A PCR test is also available to detect spores in urine or faeces. on PM there may be gross changes to kidneys with pitting and scarring of renal cortex. endoscopic kidney biopsy could be performed in the live rabbit to diagnose this infection on histopathology.
61
How is treatment of E cuniculi made?
In acute cases clinical signs may be alleviated with fenbendazole for 4 weeks. prognosis good for opthalmic disease. glucocorticois may also be given to reduce inflammation. Profoundly immunosuppressive.
62
How much blood can be taken from a rabbit? Where can you take a blood sample from?
Rabbits blood volume is 55-78 ml and 10% f this can be removed safely so sample volume is rarely a limiting factor. (5.5ml-7.8ml) Marginal ear vein, jugular vein, lateral saphenous vein, cephalic vein. Prior application of EMLA cream facilitates venepuncture & IV catheter placement.
63
describe how intraosseous catheterisation is done in rabbits?
Indications; administration of fluids or drugs in situations where intravenous access is limited or non existent. eg rabbits in cardiogenic shock or juvenile rabbits. Sites include proximal femur, proximal tibia, proximal humerus. technique - clip and aseptically prepare the skin overlying the selected bone. Infiltrate lidocaine into the local tissues and periosteum unless the rabbit is under general anaesthesia, select an appropriate needle based on the size of the bone to be catheterised and materials available - a spinal needle, a standard hypodermic needle with a piece of sterile wire or a smaller gauge needle acting as a stylet. Position the needle over the appropriate site and ensuring that the needle is straight and aligned in the direction of the bone, use it to bore a hole through the cortex of a bone (a sudden lack of resistance will be felt as the marrow cavity is penetrated). Remove the stylet and flush with heparinised saline to ensure patency. If in any doubt, confirm position by radiography. bandage the site to maintain cleanliness and restrict mobility of the limb.
64
How should urine be collected from a rabbit?
Urinalysis is an important diagnostic tool in the evaluation of many rabbit illnesses. Voided samples are easy to collect especially in litter trained rabbits but are often contaminated. If possible collection by manual expression of the bladder, cystocentesis or catheterisation is preferred. Deep sedation or anaesthetic is required for cystocentesis or urethral catheterisation. The use of benzodiazepine in the premedication or sedation protocol is helpful as it reduces incidence of urethral spasm.
65
How is nasolacrimal cannulation completed?
Indications - to facilitate flushing of the nasolacrimal duct in cases with suspected blockage or infection, to instill topical medication into the nasolacrimal duct or to perform contrast dacryocystography. Technique; apply a local anaesthetic drops to the eye. some rabbits require sedation. Gently pull out or evert the lower eyelid to expose the slit like ventral punctum of the nasolacrimal duct in the lower conjunctiva medial to the lid margin. Insert the cannula into the duct in a ventromedial direction (there should be little resistance if positioning is correct), attach a syringe filled with sterile saline, medication or contrast agent as required and flush duct. The instilled material and duct contents will be present at the ipsilateral nostril if the duct is patent. if the instillation of fluids leads to bulging of the globe, the duct has ruptured and procedure should be stopped immediately.
66
Describe techniques for oral administration of medication/food in a rabbit?
Restrain the patient in a suitable manner on an examination table on the floor or wrapped in a towel. gently insert the nozzle of a syringe into the mouth behind the incisor teeth on either side and direct towards the caudal mouth. Ensure the rabbits head is parallel with the table/floor if elevated there is a risk of aspiration. administer a small volume of liquid, remove the syringe and wait for the rabbit to swallow before administering more. this procedure must not be rushed. if the rabbit will not swallow then an alternative method must be considered.
67
Name the different routes of administration for parenteral fluids/drugs in rabbits
Subcutaneous - well tolerated in most rabbits, relatively slow absorption. Under skin at back of neck.
IM - introduce needle at right angles to centre of muscle mass, only suitable for volumes <1ml, avoid if possible as painful. (dorsal lumbar muscles that lie on either side of vertebral column, quadriceps muscles).
Intraperitoneal - Caudal to umbilicus, paramedian. Can give volumes up to 20ml, care is required to minimise risk of abdominal organ puncture.
Intraosseous - second only to IV amdinistration if rapid absorption required. Proximal humerus, tibia,femur
IV - marginal ear, cephalic vein, saphenous. Most medications that are administered IV should be administered slowly.
subconjunctival - into the bulbar conjunctiva. The use of local anaesthesia is recommended. Volume administered varies from 0.25-0.5ml.
68
Describe how to place a nasogastric tube in a rabbit
Indications; to facilitate administration of oral fluids, nutrition and medication to critically ill rabbits where syringe feeding is not possible eg patients with swallowing disorders, following extensive oral surgery or anorexic rabbits that do not tolerate frequent handling. Premeasure a 5-8f catheter from external nares to the caudal end of the sternum. instill a few drops of topical local anaesthetic into nostril, apply a small amount of lubricant to tip of catheter, elevate head and insert catheter into ventral nasal meatus, advancing ventromedially. keep neck partially flexed as catheter advances into oesophagus and advance tube to predetermined level. Radiography is recommended to ensure a correct placement of tube before administrations of fluids. Secure tube to rabbits head using a flap of tape and tissue glue or a suture. This procedure is not recommended for patients with dyspnoea of respiratory origin
69
How should rabbits be euthanased?
Euthanasia of Pet rabbits is usually performed by intravenous injection of pentobarbitone. the marginal ear vein is a useful site and the application of local anaesthetic cream will often prevent any discomfort associated with venepuncture. Nervous rabbits can be sedated e.g with a benzodiazepine or fentanyl to aid restraint for the procedure. if intravenous access cannot be achieved the rabbit can be anaesthetised by injectable or inhalational methods and the pentobarbitone injection given into a well perfused organ eg kidney or liver or directly into the heart. Intraosseous administration is also effective.
70
Describe the complete assessment of the rabbit skull by radiography
predominantly used to evaluate dental structures- includes a 5 standard views, one latera, a left and a right lateral oblieque, a dorsoventral or ventrodorsal and a rostrocaudal view. intraoral views to enable visualisation fo a single dental arcade with no superimposition are iedeal. Features to note include incisor occlusion, cheek teeth occlusal plane, orientation, length and degree of curvature of all teeth, the radiodensity of the surrounding bone and the symmetry of structures such as tympanic bullae.
71
Describe how best to take thoracic radiographs in rabbits?
Best achieved in an anaesthetised, intubated rabbit to ensure the lungs are inflated during exposure. Ideally left and right lateral and ventrodorsal views are tkane. Intrathoracic fat and he presence of the thymus can complicate interpretation. Abdominal radiography is useful for evaluation of gastrointestinal tract, liver, urinary tract and sometimes reproductive tract. it is an important tool for the evaluation of any rabbit with a distended abdomen. Gaseous distension of bowel loo[s indicative of ileus and urinary calculi or sludge are common findings. Two views should be taken.
72
What is the normal urine specific gravity for a rabbit?
Useful to assess hydration status/renal function and monitor response to fluid therapy in dehydrated patients. normal values range from 1.003 -1.036. Over 1.036 suggests haemoconcentration.
73
What may the dipstick tell you about a rabbits urine?
pH - normaly alkaline >8.0 as in other herbivores. pH < 7.0 suggestive of metabolic acidosis and nede for immediate supportive therapy whilst investigating cause. Protein: trace amounts can be normal. the alkalinity of rabbit urine makes this test unreliable. urine protein to creatinine ratio is more sensitive. (<0.4 is normal). Ketones: presence indicates ketosis, often present in cases with hepatic lipidosis, moderate to large amounts associated with poor prognosis and requirement for immediate intensive supportive care whilst investigating underlying cause.
Glucose: trace amounts can be normal, higher amounts most often associated with stress hyperglycaemia or alpha 2 agonist drugs. Blood: important to differentiate false haematuria from true haematuria.
74
What is false haematuria?
Presence of plant porphyrin pigments in urine
75
what may be different on rabbit haematology compared to dogs and cats?
Red blood cell lifespan is shorter in rabbits compared with dogs and cats so polychromasia, reticulocytes and higher red blood cell distribution width are often observed in healthy rabbits. As a general rule: PCV 45% and usg >1.036 is suggestive of dehydration.
76
What may cause regenerative anaemia in a rabbit?
Trauma, flea infestation, GI bleeding, other internal haemorrhage, intravascular haemolysis, lead toxicosis, and very high doses of ivermectin.
77
When may non regenerative anaemia occur in rabbits?
with chronic disease e.g otitis media, periapical abscessation, endometritis, renal disease and neoplasia e.g uterine adneocarcinoma, lymphosarcoma.
78
What is an elevated PCV indicative of?
haemoconcentration - dehydration
79
When may leukocytosis occur in rabbits?
Total white blood cell count varies diurnally and rabbits do not develop marked leukocytosis as other species do in response to bacterial infection, stress or exogenous corticosteroid administration. low total white blood cell counts are most often associated with chronic disease. the differential white blood cell count is more often important than the total white cell count itself.
80
What causes a change in the neutrophil/lymphocyte balance?
Of particular relevance the neutrophil: lymphocyte ratio is frequently altered in rabbits suffering from inflammatory disease or stress. The percentage of lymphocytes should equal or exceed the percentage of neutrophils in the normal state. Relative neutrophilia/lymphopaenia is one of the most common abnormalities detected.
81
What are atypical lymphocytes suggestive of?
lymphoma - a relatively common neoplastic condition in the rabbit
82
Why may glucose be elevated or lowered in a rabbit?
mild - moderate hyperglycaemia is frequently associated with stress and pain, eg GI obstruction. diabetes mellitus has not been reported in pet rabbits and is an unlikely diagnosis given herbivorous glucose metabolism. instead, persistent hyperglycaemia is sometimes observed in patients with terminal gut stasis and intestinal obstruction and is a poor prognostic indicator. Hypoglycaemia is significant especially if rabbit is ketotic and may be observed in cases of starvation or anorexia with associated hepatic dysfunction.
83
What may cause low levels of protein?
Low levels may be associated with malnutrition, protein losing enteropathy or protein losing nephropathy.
84
What is different about calcium levels in rabbits to other animals?
Total plasma values reflect dietary intake so take care - not to over interpret seemingly high values. rabbits have a higher and more variable normal total plasma calcium levels compared to other species. hypocalcaemic tetany may be seen in lactating does and marked hypercalcaemia may be associated with chronic renal disease or neoplasia.
85
What may cause high levels of phosphate in the rabbit?
Phosphate: high levels may be associated with renal disease and low levels with dietary deficiency or poor intestinal absorption. Phosphate metabolism is complex and values must be carefully interpreted in light of other findings. Serum bilirubin; raised levels suggest biliary obstruction.
86
what is GGT in the rabbit?
in the rabbit this enzyme is found predominantly in the kidneys with lower activity in the liver.
87
what may an elevation in amylase suggest?
Lower normal values compared with other species, elevation associated with pancreatic disease or pancreatic duct obstruction.
88
Describe how calcium metabolism is unique in rabbits?
rabbits excrete alkaline urine. the kidneys of the rabbit are unipapillate where one papillae and calyx nter the ureter directly, in comparison to most other mammals that have multipapillate kidneys. Unlike most mammals, rabbits total blood calcium levels reflect dietary intake. Dietary calcium is readily absorbed in the intestines and does not epend on activated vitamin D. As a result, both ionised and total calcium serum concentrations are elevated compared with those of other species (ionised calcium 1.6-1.82 , total calcium 2.17-4.59). Unlike other species, the rabbit is absolutely dependent on the kidney for proper calcium osmoregulation. the renal fraction of excretion with calcium in the rabbit is 45-60%, compared with less than 2% in other mammals which eliminate excess calcium through the intestinal tract. the excreted claicum precipitates int he alkaline urine to form calcium complex crystals, giving the urine a thick and creamy appearance.
89
What is the most common serological test used in rabbits?
For exposure to the parasite encephalitozoon cuniculi. although rarely used clinically, other tests to consider may include serological assays for toxoplasma gondii, myxomatosis, viral haemorrhagic disease and treponema cuniculi.
90
When should microbiology be considered for rabbits?
The submission of samples for aerobic and or anaerobic culture should be considered in any case in which a bacterial infection is suspected. abscesses ar ea common condition in pet rabbits and to improve the chance of culturing the relevant organism, consider submitting a piece of or a swab of the abscess wall rather than as or as well as the abscess contents. fungal culture may be indicated in cases where cytology or clinical appearance suggests a fungal aetiology eg dermatophytosis, aspergillosis.
91
What effect may oral antibiotics have in rabbits?
May upset gut microflora and cause dysbiosis, favouring the proliferation of pathogenic bacteria such as clostridial species. penicillins carry the highest risk of dysbiosis as well as other beta lactamases and lincosamides and these drugs should only be given parenterally. High fibre food and the use of probiotics can help maintain the balance of caecal microflora in rabbits receiving antibiotics and there should be close monitoring for the development of diarrhoea.
92
Name the specific contraindications with drugs in rabbits?
Great care should be taken with corticosteroids in rabbits - both topical and systemic. in general they should be avoided. rabbits are very sensitive to the adverse efefcts of these drugs. other specific contraindications are; fipronil both spray on and spot on associated with mortality, tilmicosin associated with sudden death, hypermotility treatments such as kaolin or montmorillonite clay can precipitate fatal gastrointestinal stasis, loperamide - use for severe life threatening diarrhoea only with associated abdominal pain - not generally recommended.
93
What are the main problems with rabbit anaesthesia?
The main problems are their high susceptibility to stress and underlying respiratory disease. to optimise perioperative care the rabbit should have premedication including preemptive analgesia, intravenous catheterisation to allow fluid therapy and access for emergency drugs and should be intubated to maintain the airway and allow IPPV when required. oxygen should be supplemented by face mask/induction box soon after any sedative/induction agents are given.
94
How can pain be recognised in rabbits?
They are prey species and are nervous sensitive animals that are less likely to show visible signs of pain than dogs an dcats. pain distress and discomfort are all difficult to assess in rabbits, particularly in the hospital environment where excessive background noise may prevent the rabbit from relaxing. signs of pain in rabbits include anorexia, a hunched posture, tooth grinding, abdominal pressure. Facial clues - orbital tightening, nose shape, cheek flattening and whisker position.
95
What is the most common response to pain and stress in rabbits? how can stress be minimised in a hospital setting?
The most common response to pain is anorexia and gastrointestinal stasis (ileus). practical ways of minimising stress in rabbits in the hospital environment are; have a separate waiting area away from cats and dogs, or keep in car untill called, use a separate consulting room or have consultations at different times with room thoroughly cleaned after predator species. have a separate hospitalisation area out of sight and preferably sound of predator species. If using a dog/cat kennels clean thoroughly to remove odours. Provide a hide box in kennel, use separate outer clothing, hospitalise with a companion wherever possible. provide a familiar diet and water presentation. provide a litter tray if rabbit is used to this. use sedation if appropriate.
96
Describe an appropriate pre operative care regime for a rabbit
it is not necessary to fast rabbits before anaesthesia as they are unable to vomit. starvation leads to disruption of normal motility, hindgut fermentation and a risk of hypoglycaemia. ideally the rabbit should be encouraged to eat food up to 1 hour prior to induction of general anaesthesia - anaesthetic candidates are often dehydrated and may be hypoglycaemic and this must be corrected first (fluid therapy and assisted feeding). rabbits with overt respiratory disease are a high risk and ideally this should be treated before anaesthesia is attempted. Pre emptive analgesia should be given in the pre operative period or at induction.
97
which premedications are suitable for use in rabbits?
Fentanyl/fluanisone, medetomidine, xylazine, acepromazine, diazepam or midazolam. Face mask induction without prior use of premedication should be avoided. rabbits breath hold when exposed to all volatile agents, even at low concentrations for periods up to 2 minutes, which induces bradycardia. Fentanyl/fluanisone or another premidcant followed by mask induction results in a smooth onset of anaesthesia. Many regimes are suitable in rabbits and ideally a balanced approach combining injectable and volatile agents minimises the risk of side effects.
98
What are the uses of fentanyl?
hypnorm is licensed for tabbits in Uk, provides restraint and analgesia. in combination with a benzodiazepine provides muscle relaxation and increases depth of anaesthesia. recovery can be speeded by reversal of the fentanyl with a partial agonsit eg butorphanol, buprenorphine or nalbuphine. this reverses the respiratory depression & some of the sedation.
99
What does propofol do in the rabbit?
Produces short periods of light anaesthesia only.. higher doses given in an attempt to produce a surgical plane of anaesthesia often result in dose dependent respiratory depression & cardiac depression. given slowly as an induction agent enables intubation & maintenance with an inhalant.
100
What does alfaxalone do in the rabbit?
Produces smooth rapid induction. should be used with a premedicant i.e buprenorphine. current dose used 2-3mg /kg diluted in equal volumes of saline given IV to effect.
101
what is ketamine used for in rabbits?
when used alone even at high doses it has limited effects in rabbits & small mamamls. it provides restraint but the degree of analgesia is insufficient for surgery. Ketamine in combination with a sedative or tranquiliser produces light to medium planes of anaesthesia. It is most efefctive when combined with an alpha 2 agonist as these agents have analgesic activity.
102
How long should a rabbit be preoxygenated?
allow the rabbit to breathe 100% oxygen for 3-4 minutes before intubation is attempted. Monitor SPo2 and mucous membrane colour during intubation. endotracheal tube size 2 -3.5mm, clear and uncuffed is preferable. with all techniques never force the tube into the larynx as this will cause haemorrhage and oedema. the use of a local anaesthetic spray applied to larynx may aid laryngeal relaxation.
103
What circuit should be used in anaesthetic?
An ayres T piece circuit or bain circuit should be used.
104
how can depth of anaesthesia be examined?
Depth of anaesthesia should be monitored by the use of the ear pi nc or the hind limb toe pinch both of which should be just absent for surgical anaesthesia. standard monitoring equipment - capnography, ECG, pulse oximeter should be used wherever possible. eye position is not useful in the rabbit and the palpebral reflex is not lost until the animal is dangerously deep. body temperature should be continually monitored and maintained at 39C.
105
Which analgesics should be used in rabbits?
Analgesics such as buprenorphine or butorphanol are indicated in most cases and can be used safely in dehydrate dpatients. NSAIDs e.g meloxicam or carprofen can be used alone or with buprenorphine but should not be used in dehydrated patients. continuous rate infusions are now being used commonly in rabbit practice e.g low dose ketamine, dexmedotomidine, morphine and allow a lower plane of anaesthesia and prevent peaks and troughs of analgesia post operatively. the use of local anaesthesia and nerve blocks also very useful in conjunction with systemic analgesia. bupivicaine and lidocaine when used in combination provide rapid onset and long duration.
106
What is ranitidine useful for?
Prokinetics are often required to stimulate GI motility. prokinetic and antacid actions makes ranitidine a very useful drug in the treatment of gastric stasis and ileus.
107
What other prokinetics can be used in the rabbit?
Metoclopramide has both central and peripheral effects - antiemetic and anti-depresssant and prokinetic. the prokinetic effects of metoclopramide are not as potent as cisapride and are limited to the proximal GIT. CIsapride is a potent prokinetic and facilitates and restored motility throughout the length of the GIT.
108
How should rabbit skin be sutured?
Hydrolytically degraded suture materials stimulate weaker adhesions than catgut. haemostatic clips are excellent for vessel and small pedicle ligation with minimal adhesion formation. Continuous subcutilar skin closure reduces the risk of removal of sutures by the rabbit. cryanoacrylate tissue adhesive can be used to close skin that is not under tension or to support skin sutures, although some rabbits will chew and groom out the glue. Skin staples are fast to place and are not easily removed by rabbits.
109
Describe ovariohysterectomy in the rabbit
recommended for all non breeding female rabbits as a preventative measure against uterine adenocarcinoma. additional indications may include aggressive or hypersexual behaviour, nest building and fur pulling. sexual maturity is reached in small breeds about 4 months and large breeds about 8 months. Generally spayed 5-6 months. Ovariohysterectomy achieved via standard ventral midline approach with the incision made half way between umbilicus and pubis. abdominal musculature is extremely thin and care should be taken when entering the abdominal cavity. The caecum and bladder lie directly under the incision and iatrogenic damage is common. Large amount of periovarian and periuterine fat. TTwo uterine horns, no uterine body, two cervices. Uterus is fragile. Uterus is turgid bright pink and easily identified. Ovarian vessels are small and haemorrhage is rare. ligatures placed using synthetic absorbable suture material. Vessels within the broad ligament may also need to be ligated if they are well developed. The uterine vessels lie several millimetres lateral to the uterus and should be ligated separately followed by a transfixing ligature around the cranial vagina, oversewing the vaginal stump oven performed to prevent urine contamination of abdomen. Uterine adenocarcinomas can occur in rabbits that have been spayed with ligaton proximal to the cervices. Abdominal and skin closure is routine.
110
Describe orchiectomy in rabbits? (castration)
recommended from 4-5 months of age when maturity is reached. The indications include reduction fo aggressive or hypersexual behaviour, cessation of breeding and cesation of urine spraying. rabbits have an open inguinal ring, therefore closed castration should be used or an open technique followed by closure of the tunic. in the intact rabbit, large inguinal fat pads associated with the epididymis prevent herniation and intestinal strangulation. these lie in the inguinal canal when the testes are in the scrotum. the rabbit is placed in dorsal recumbency and the scrotum and prescrotal area is surgically prepared. Great care should be taken not to cut the skin in this area which is extremely thin. There are two methods of castration commonly used;
1 - incision over the scrotum on each side taking care not to cut through the vaginal tunic. the testis is removed from the scrotum and double ligatures placed around the cord, prior to removal of the testis. the subcutaneous tissue and skin can be sutured as this tends to be more aesthetically pleasing to the client but is not always necessary.
2- A prescrotal incision on either side. tunic also incised and castration performed open with double ligatures again placed around the vas deferens and the vascular structures. following removal of the testis the tunica is closed with a continuous suture pattern and the skin closed routinely. Male rabbits hsould be kept separate from entire females for 6 weeks post operatively.
111
Describe how C section is done in a rabbit?
Indications for C section include uterine inertia unresponsive to medical treatment or dystocia. the rabbit must be stabilised prior to surgery. routine midline abdominal approach with an incision from xiphoid to pubis, avoiding the enlarged mammary glands and associated blood vessels. Gravid uterus packed off from abdomen with saline moistened swabs. The uterine incision is made over a fetal limb nearest the cervices taking care to not to lacerate the fetus. fetus removed with placenta where possible. Umbilicus is clamped and kitt handed over to assistant. Foetuses are milked out from this incision where possible. uterine wall closed using double layer inverting suture pattern oxytocin should be administered. lavage abdomen with warm sterile saline.
112
What may cause subcutaneous abscessation?
Can result from periodontal disease, trauma, foreign bodies, bacteraemia secondary to systemic disease including periodontal diseas.e bacteria usually isolated include pasteurella multocida, staphylococcus aureus, proteus spp, pseudomonas, bacteroides, fusobacterium, strep, e coli, corynebacterium pyogenes and kelbsiella. pulmomary abscesses can result from chronic respiratory diseaese or secondary to bacteraemia.
113
How should abscesses be removed?
Complete surgical excision leaving the wall intact with a substantial margin so that all the contaminated tissue is removed is the recommended treatment. the pus usually is sterile therefore always submit the abscess capsule or affected bone for bacterial culture and antibacterial sensitivity. Excision of large abscesses may require use of skin flaps for closure of the defect. Use of antibiotic impregnated polymethylmethacrylate beads has been advocated following excision or where total excision is not possible. Antibiotics used include gentamicin, piperacillin, amikacin.
114
why should calcium hydroxide be avoided in rabbits?
Causes severe soft tissue necrosis and therefore its use should be avoided.
115
describe lateral ear canal resection in rabbits?
Chronic otitis can be very frustrating and difficult to treat in rabbits especially lop breeds and lateral ear canal resection can provide good relief. the technique is very similar to that of the dog. two parallel incisions are made at the base of the ear that follow into the line of the pinna. skin and subcutaneous tissue are dissected free and reflected rostrally to reveal vertical canal. a further to incisions then made into lateral wall of vertical canal and cartilage dissected carefully. Dissection continued down to level of the horizontal canal. Once exposed the flap of cartilage from the vertical canal is removed and cartilage of horizontal and vertical canals is sutured to the surrounding subcutaneous and skin tissues using absorbable sutures.
116
Why is the differential white blood cell count often more importat than the total white cell count in rabits?
Neutroophil: lymphocyte ratio is frequently altered in rabbits suffering from inflammatory disease and or stress. The percentage of lymphocytes should equal or exceed the percentage of neutrophils in the normal state.
117
Describe the unique calcium metabolism in rabbits?
Rabbits excrete alkaline urine. the kidneys of the rabbit are unipapillate, where one papillae and calyx enter the ureter direclty , in comparison to moost other mammals that have multipapillate kdneys. Unlike most mammals, rabbits total blood calcium levels reflect dietary intake, dietary calciuum is readily absorbed in the intestine and does not depend on activated vitamin D. as a result both ionised and total calcium serum concentrations are elevated compared with those of other species (ionised calcium 1.6-1.8mol, total calcium 2.17-4.59). unlike other species, the rabbit is absolutely dependent on the kidney for proper calcium osmoregulation. the renal fractional excretion of calcium in the rabbit is 45%-60% compared with less than 25 in other mammals, which eliminate excess calcium through the intestinal tract. the excreted calcium precipitates in the alkaline urine to form calcium complex crystals, giving the urine a thick and creamy appearance.
118
What therapeutic agents should be avoided in rabbits?
Penicillins - carry the highest risk of dysbiosis as well as other beta lactamases and lincoosamies. Specific contraiindicatios are; fipronil, tilmicosin, hypermotility treatments such as koali or montmorillonite clay, loperamide - for life threatening diarrhoea only associated with abdominal pain.
119
What kid of dentition do rabbits have?
Aradicular hypsodont (open rooted, long crowned)
120
What is normal for rabbit urine that differs frmo other species?
Urine is the major route of excretion for excess calcium that has been absorbed an as such calcium crystalluira is a common normal finding. Porphyrinuria is also common in normal rabbits and in general this species has a high fluid intake.
121
Which lymph nodes are palpable in the normal rabbit?
Popliteal and prescapular palpable in normal rabbit. submandibular, inguinal and axillary palpable only if enlarged.
122
Describe the clinical differentiation of non obstructive ileus and obstructive ileus
Non obstructive - bright and alert initially, becoming more depressed and dehydrated gradually, gradually reducing appetite and faecal volume/size.
Obstructive - may initially appear bright, but rapidly becomes depressed, acute anorexia, acute history of no faeces.
