Rabbits 1

taxonomy

order = lagomorpha

family =lepordiae

all domestic are descendants of european wild rabbit 

they’re not rodents

important data

head

large erect pinnae

large proturbent eyes

cleft lip 

twitchy nose

vibrissae

specialised dentition 

ears 

useful for bunny = thermoregulation, funnelling sound - can rotate 270^o

useful for us = administrating meds and fluids, blood sampling - use marginal ear vein for blood sampling 

can be sensitive - blood vessesl fragile and easily damaged, use local aneasthetic and be gentle

eyes 

positioned laterally - wide field of view

have 3rd eyelid - nictitating membrane

harderian gland - produces very stable tear film

single ventral lacrimal punctum draining into nasolacrimal duct - runs so close to apices of cheek teeth so may cause problems 

proturbent eyes = higher risk of trauma 

underlying dental disease leads to eye issues 

ophthalmic exam = merangiotic retina - blood vessels coem out the cente and run out horizontally in arrow band , no tapetum - have to look upwards in exam to see the blood vessels, no light reflection

large retrobulbar venous plexus(orbital venous sinus) 

• can cause eyes to become more proturbent looking - frightened rabbit with increased blood pressure or diseased venous plexus 

blindspots = very tip of nose and directly behind them

ocular muscles and drainage

additional extraocular muscle - depressor palpebrae

rectus dorsalis m. = used to stabilise globe during surgery

large retrobulbae venous sinus outside extraocular muscles 

drain via external jugular 

dentition

hypsodont teeth - reserve crown, enamel extends below gumline, aradicular/elodont (open rooted/ no true root)

peg teeth 

rate of eruption = incisors = 3mm/ week, cheek teeth = 3mm/month

dental formulae = I 2/1 C 0/0 PM 3/2 M 3/3

dental disease common - chronic alters skull morphology, can evelop dentalspur in not enough fibre in diet 

high CHO low fibre diet results in reduced tooth wear and elongation of crown of teet, leads to occlusion of cheek teeth at rest which puts pressure on crowns 

continues the mouth is forced open resulting in retrograde pressure forcing apices of teeth back into bone( bony swelllings develop on mandible)

chewing becomes difficult and anatomy of chewing altered - up and down instead of side to side 

results in formaation of enamel spurs

jaw forced apart and incisor teeth wear incorrectly and then see incisor malocclusion and elongation 

full dental examination and corrective dentisty requires anaesthetia

very strong tongue(torus), fleshy teeth and small gape makes it difficult to fully examine mouth of conscious rabbit

nose

twitching is normal even at rest

rate increases if interested in something 

v sensitive to touch 

blind spot here 

sensitive pads on nares

presence of vibrissae

respiratory system

obligate nasal breathers

30-60 bpm

small thoracic cavity - tidal volume = 4-6ml/kg

high chest wall compliance

low functional residual capacity 

diaphragmatic contraction drives breathing 

very sensitive to respiratory irritants 

R lung = cranial, middle, caudal and accessory

left lung = cranial, middle, caudal 

thymus persisits in adult rabbit, found in cranial mediastinum

intubuation hard- long tongue, small glottis, narrow oropharynx, laryngospasm

CV system

HR = 150-300 bpm

systolic blood pressure = 90-135mmHg

total blood volume = 50-75ml/kg

little collateral circulation

electrical conduction system simple - SAN consists of small group of cells

venupuncture sites = jugular, lateral saphenous, cephalic, marginal ear vein

most useful site depends onw ahtyou want to do 

venupuncture sites

cephalic good for catheterising

digestive systen

hindgut fermenter - large stomach, huge caecum

highly efficient food converters

select concentrates over fibre

dental disease tends to occur secondary to - poor diet

fibre essential for gut health

have a gall bladder

starts at mouth

grinding action of cheek teeth

strong tongue ensures all food is masticated prior to swallowing

4 pairs of salivary glands - parotid, sublingual, zygomatic, mandibular

amylase rich saliva released in response to presence of food in mouth 

oesophagus = 3 layers of striated muscle extending all way to cardia of stomach

stomach = lies left to midline. thin walled and j-shaped. well developed cardiac sphincter meaning no vomitting - ruptured stomach is common postmortem finding - not necissarily cause of death

pH 1-2 means stomach and SI are practically sterile - neonates have 5-6.5 = more suceptible to bacteria, milk oil produced from 0-6 weeks 

SI = accounts for 12% digestive tract volume, secretes enzyme called MOTILIN - stimulates motility in SI,colon and rectum(no effect on caecum), released in response to fat, inhibited by carbohydrate 

terminal ilieum ends in sacculus rotundus at junction with colon and caecum - sometimes called caecal tonsil

sacculus rotundus is composed of lymphoid tissue - defence against bacteria

caecum = 40% of GI volume, ends in veriform appendix

proximal colon - 50cm, 3 subsections - 3 haustra/ sacculations, single haustra, fusus coli(regulates passage of ingesta into distal colon, separates hard from soft pallate

distal colon = 90 cm , no sacculation, long

veriform appendix composed of lymphoid tissue 

hindgut fermentation

in caecum microorganisms perform fermentation producing VFAs which absorb across caecal wall

bacteria replicate in caecum, forming vital source of protein

caecal contents are expelled as caecotrophs which are eaten from anus

caecal pellet protected from stomach pH by mucus covering - bacterial replication continues

digestion of caecal pellet delivers protein to animal

main VFA produced by caecal fermentation is acetete( then butyrate then proprionate)

gut motility

derangement of GIT motility in rabit is common and often fatal

ANS controls GI tract motility, particularly fusus coli

hormonal control - motilin/ prostaglandin

presence of indigestible fibre in gut (cellulose and lignin) - encourages motility, reduces caecal retention time

hard faeces

contractions in proximal colon separate indigestible particles from liquid component

indigestible contents move to centre of lumen further water absorbed

hard pellets produced

soft faeces

smaller particles and liquid content move into peripheral lumen

antiperistalysis returns them to caecum for further fermentation

caecum contracts to exspel contents into proximal colon which then move rapidly through distal colon with no further absorption 

caecotrophs

produced about 8 hrs post feeding - eaten directly from anus

provide source of protein, vit B and vit K

high protein, low fibre diet discourages consumption

high fibre, low protein diet encourages consumption

diarrhoea uncommon

repro system

when do rabbits reach sexual maturity - small breeds = 4-5 months, large breeds = 5-8 months

reproductive capacity of around 60 kits per yr - can rebreed immediately after giving birth 

induced ovulator - no well defined oestrus cycle but periods of sexual receptivity, ovulation occurs around 10-13hrs after coitus 

gestation length = 30-33 days 

parturition = called kindling, lasts around 30mins, rarely problems with dystocia, young born altricial and require maternal care 

kit care

feed only once or twice daily for 3-5mins at a time - rabbit milk has higher fat, protein and calorie content than other mammalian milk, high nutritive value(13% protein, 9%fat, 1%lactose, 2.3%minerals)

maternal immunty is placental - hand reared kits prone to mortality due to lack of milk of oil - milk oil is a antimicrobial substances produced by a reation between mothers milk and neonates substance 

kits start to take solid food around day 18-21

lactating does have increased water requirement - up to 10 fold

sexing rabbits

best sexed at weaning = 5-8weeks

check and double check

male rabbit - no nipples

female = doe

male = buck 

male repro system

penis sits within rounded penile sheath - can be extruded using gentle digital pressure from 2 mo old, no os penis

2 hairless pockets can be seen either side of urogenital area = scent glands, often have hard/crusty material within 

scrotal sacs cranial to penis - large epidydimal fat pads, open inguinal canal meaning testes can easily be retracted into abdomen 

accessory sex glands - seminal vesicle, prostrate, paired bulbourethral glands 

castration can be carried out from 3 months age - make sure testes present in scrotum - castrate to - stop ability to breed, easier to litter train, reduce aggression and allow safe pair bonding with other rabbits of either sex 

testes descend into scrotal sacs at around 10-14 weeks 

female repro system

has duplex uterus - large saccular vagina, 2 cervices - left and right

long convulated oviducts

mesometrium stores fat = increases with age - can be challenging to neuter later 

uterus and ovarian pedicle - friable 

pseudopregnancy is possible - caused by infertile mating or presence of a male

caused by secretion of progesterone from CL - see enlarged mammary glands and abdomen, may pluck belly and make nest

regresses naturally but can reoccur multiple times 

can be neutered from 10-12 weeks but uterus may be hard to find, witing until 16-20 weeks means larger

why spay = negates risk of uterine pyometra or carcinoma, reduces risk of mammary tumours, reduces aggression and risk of fighting, reduces phantom pregnancies, population control 

haematological features

RBCs - HCT 33-55%, RBCs smaller than canine but larger than feline, anisocytosis and polychromasia are normal on a smear, lifespan 57 days

WBCs - lymphocyte most common circulating leucocyte, neutrophils called heterophils as cytoplasm stains pink-red, eisonophils have a bilobed nucleus and bright pink staining granules 

musculoskeletal system

skeleton very light and flexible - accounts for only 6-8% BW

vertebral formula - C7, T12, L7, S4,Cd16 - powerful epaxial and hindlimb muscles 

tibia and fibula partially fused

5 digits on forelimb

4 on hindlimb - at rest entire plantar aspect of hindlimb from toes to hock rests on ground 

no footpads - furry feet 

why does lifestyle of domestic rabbit make them prone to fractures and osteoporosis -  low calcium levels, reduced exposure to sunlight, lack of exercise 

integument

rabbit skin is really thin and elastic

3 hair types - long guard hairs, short guard hairs, undercoat 

fur types - satin, rex, wool, normal 

fury all over except nose, scrotum and inguinal area 

have twice yearly molt - spring/autumn - starts at head, travels down body

does develop large dewalps 

normal to have some hair in stomach through self grooming

scent glands - present in anal glands, inguinal glands and chin glands, found in both sexes

feet

no footpads just fur

can predispose to ulcerative conditions - ulcerative pododermatitis, generally exacerbated by hard cage surfaces and unhygienic conditions, more common in overweight animals or those with thin coat 

scent glands present in both sexes - 3 sets 

urinary system and calcium excretion 

kidneys unipapillate - single medullary pyramid

dangerously high serum levels avoided by action of PTH, calcitonin and active vit D3 - excess calcium excreted by kidney, forms calcium carbonate crystals in urine once reabsorptive capacity kidney is reached 

urine = pale yellow to dark red - usually cloudy

excessive prolonged dietary calcium intake can result in urolithiasis

pH = 8-9 

rabbits absorb all available dietary calcium through cut then deal with it by excretion via kidneys 

serum calcium conc = 3.25-3.75 mmol/l

rabbit physiological data

lifespan = 5-10 yrs

adult weight = 2-5kg

sexual maturity = 4-8 months

litter size = 1-8

gestation length = 30-32 days 

behaviour

social and gregarious species - live in small bonded family groups

prey species

use subtle means of communication = scent marking, body language 

crepusular - most active at dawn and dusk 

ensure of stability of - environment and population

handling

avoid touching nose

stroking rountod cheeks and chin can mimic natural mutual grooming behaviour 

dont pick up unless have to 

support hindlimbs to avoid damage to spine 

tonic immobility

cortisol increase

respiraotry rate increases

HR increases 

a fear response and should not be used as routine restraint or instead of sedation or anaesthesia 

diet and feeding

hindgut fermenters - fibre is essential

browsing creatures 

can use food as enrichment 

increased dietary fibre = decreases stress - ad lib feeding of long fibre essential 

very selective - choose grains and pulses over grass pellets in conc diet - problematic because - low fibre = increased dental disease and reduced gut health, high concentrates = lots of energy in small meal

feeding

cereal and concentrate mixes bad

• high protein, high calorie

• selective feeding

• reduced caecotrophy

• boredom

• dental disease

• obesity

starchy foods lead to GI disturbances 

feed grass - 80% diet ad-lib

mixture of timothy, fescue, cocksfoot and meadowgrass ideal

alfalfa - only growing rabbits as high protein and clacium levels, lower fibre

clover is very high energy = weight gain

supplement with edible wild leafy plants and leafy greens(carrot tops, beet tops, spinach, rocket), fruit only as treat or training aid

fibre

indigestible fibre - vital for gut motility

• ligin and cellulose - from secondary plant wall

• no nutitional value 

• not easily fermented 

digestible fibre - for energy 

• smaller particles from primary plant wall

• fermeneted in caecum 

• results in VFA production 

excess digestible fibre → caecal dysbiosis 

calcium

amount absorbed depends on amount of calcium in gut

calcium regulation is done by kidneys not gut - adapted to absorb calciumm if body needs and excrete if levels are adequate

0.6-1% required for optimal health

intake depends on calcium content of food its offered and how much it chooses to eat

neonates

stomach pH 5-6.5

milk oil produced due to reaction of doe’s milk with digestive enzymes = antimicrobial

as kit starts to take plant matter in bacteria colonise caecum and pH in stomach drops - milk oil no longer necessary once stomach pH down to 1-2

housing 

space to - sit up with ears erect, hop,lie down fully stretched, play, eat and drink, maintain hygiene

10-20 degrees

variety of levels and spaces

scent marking surfaces

access to outside 

always be large enough to accomodate 2 rabbits

min enclosure of 6ft X 2ft X 2ft plus access to an outdorr run of 8ft

management regime depends on environment

keep it clean - preserve scent marking

clean toilet ares at least daily - urine/faeces

dirty environment predisposes to flystrike/ myiasis, pododermatitis, respiratory disease

routine health care

vaccinations - myxomatosis, RHD(viral heamorrhagic disease - caused by calcivirus)