THE LABORATORY RABBIT handling and basic techniques

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THE LABORATORY RABBIT - handling and basic
techniques

• FELASA and
• The National Laboratory Animal Center, Oslo.

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• These slides shows you how to pick up, hold and
  restrain laboratory rabbits. It includes methods
  of administering various substances and the
  techniques of blood sampling. The aim is to
  provide a basic guide so that you can practice
  the various procedures.

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Slide 2.

• All demonstrations are with fully conscious
  rabbits unless otherwise stated. The key to
  restraining rabbits is deliberate, firm but
  gentle handling. They then feel secure and
  several procedures can be carried out
  single-handed.

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Slide 3.

• Adult rabbits are housed singly shortly after
  weaning. Fighting is common in both sexes even
  among litter mates.

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Slide 4.

• To reduce experimental variation rabbits should
  be fed entirely on pelleted diet. The pellets are
  usually smaller than those for rats and mice
  this is because the rabbit tends to eat rather
  than gnaw at its food. Water must be available at
  all times.

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Slide 5.

• Rabbits are generally quiet, docile animals but
  they can be easily frightened. Usually when the
  cage is opened they run away to a corner so,
  first, reassure the animal by stroking it along
  its back.

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Slide 6.

• So that we can demonstrate the procedure for
  picking up a rabbit more clearly we have, in the
  following slides, removed it from the cage.
  Firstly, grasp a handful of loose skin from the
  scruff of the neck and draw the rabbit toward
  you.

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Slide 7.

• Now slide your hand under the belly and between
  the hind legs. Use your forearm to take most of
  its weight as you lift.

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Slide 8.

• A rabbits hind legs are very powerful, so, note
  here how they are restrained. Get your fingers
  and thumb firmly around each leg above the hock,
  with one finger between the legs so that you do
  not lose your grip.

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• When you lift the rabbit out of the cage,
  supporting its weight on your arm and keeping a
  firm grip on the hind legs, it is advisable to
  tuck its head under your arm. This usually keeps
  it quiet.

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Slide 10.

• It is often a good idea that when you return a
  rabbit to its cage it must go in backwards. If
  you put it in head first it usually leaps forward
  and may injure itself or you.

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Slide 11.

• To sex a rabbit keep your grip on the scruff and
  sit it upright on your knee. Releasing the hind
  legs press with your forefinger in front of the
  genital opening. In the male the penis is
  extruded but in the female only a vulval slit is
  visible. The testes are usually retracted in the
  male.

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..and here is a she-rabbit..

• Sexing of young animals are often very difficult,
  but not at the time of weaning (5-6 w).

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• Subcutaneous injections are made into a fold of
  loose skin, the most convenient site being over
  the shoulder blades. With one hand lightly
  restrain the rabbit using gentle pressure over
  the shoulders. Lift a fold of skin and check that
  the needle is actually subcutaneous by feeling
  the point under the skin.

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Slide 13.

• For intra-peritoneal injections an assistant must
  assist holding the head lower than the back legs
  (so that the abdominal organs fall away from the
  injection site). The assistant holds the animal
  by the scruff and the hind legs allowing its body
  to rest on the forearm.

• Put the needle tip slightly to the side of the
  midline half way between the rear edge of the
  breast bone and the front edge of the pelvis.
  Point the needle toward the centre of the
  abdomen. Push it in with a sharp jerk going no
  further than 1 cm into the abdomen.

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Intramuscular injection - Sorry, no picture

• The best site for intramuscular injection is the
  adductor muscle mass at the front of the thigh.
  Restrain the animal by tucking its head under
  your elbow and holding the muscles to be injected
  with your fingers. Introduce the needle at right
  angles to the skin and inject 6-8 mm below the
  skin surface.

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Intravenous injection
Vein
Artery
Vein

• Intravenous injections are normally given into an
  ear vein. Those in the ear are prominent
  especially after local heating. In this slide of
  a shaved ear the lateral veins and the central
  artery are marked.

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Slide 16.

• As a beginner you will find it easier to inject
  intravenously if someone holds the rabbit for
  you. First pluck or shave the injection site.
  Then the assistant puts up the vein by
  restricting venous return at the base of the ear.
  Insert the needle, bevel uppermost, at a shallow
  angle and slide it into the vein.

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Slide 17.

• When the needle is in the vein change your grip
  to fix the needle and ear between your finger and
  thumb. Tell your assistant to release the vein
  before you inject. If the needle has been
  positioned correctly the blood in the vein will
  be washed away by the inoculum.

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Slide 18.

• When you withdraw the needle use digital pressure
  to prevent any bleeding. Alternatively, as shown
  here, a paper clip opened up and pushed half way
  across the vein does the job for you BUT remember
  to remove it after a minute or two.

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Oral feed - gavage

• Accurate and reproducible oral dosing is done via
  a stomach tube. A gag prevents the rabbit from
  biting the tube. It should be cylindrical and
  about 1,5 cm in diameter and is best made from
  plastic. A pliable rubber urinary catheter 2-4 mm
  in diameter makes a convenient stomach tube.

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Slide 20.

• You should estimate the length of tube required
  to reach the stomach before insertion and mark
  it. The correct measure is the distance from the
  nose to the rear edge of the breastbone, as shown
  on the slide.

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Slide 21.

• Introduce the gag to the side of the mouth behind
  the incisor teeth so that the hole is central and
  allows easy entry for the stomach tube.

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• The tube is passed more easily if moistened. Push
  it through the gag and with gentle pressure the
  animal will swallow reflexly. Attach the syringe
  or doser to the tube and give the solution slowly.

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Slide 23.

• Place the rabbit centrally on a cloth.

• Pull one side then the other tightly across the
  rabbits back making sure that the front feet are
  firmly held within the cloth. Use large pins or
  nails to hold the cloth in position behind the
  ears.

• Blood collection from a rabbit is much easier
  when it is securely restrained. This can be done
  single handed with elementary materials. In this
  posture a rabbit feels secure and will sit
  comfortably for surprisingly long periods

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Slide 25.

• Pull the cloth tightly over the rabbit and put a
  second pin over the back. Now take the loose
  piece of cloth behind the rabbit and fold it
  tightly over the rump.

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Slide 26.

• Pull this fold over the back and pin it into
  place.

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Slide 27.

• A drop of blood soon exudes from the cut,
  sufficient for microscopic smears or micro
  samples.

• Small blood samples can be collected from a
  lateral ear vein. Shave or pluck the site and cut
  the vein longitudinally for about 1 mm using a
  blood lancet or small scalpel blade

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Slide 28.

• Samples up to 5 ml or more can be collected if
  the venous return is obstructed and the
  collecting vessel is held under the bleeding
  point. Clotting can be reduced if Vaseline is
  smeared over the skin. When you have sufficient
  blood release the pressure on the vein. Control
  bleeding as shown previously.

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Slide 30.

• Samples larger than 5 ml may be collected by the
  use of a vacuum tube in the central artery, This
  yields quickly a cleaner sample.

• Insert the needle with the bevel to the side and
  when it is in position that the needle point is
  uppermost. The bevel thus lies in the vessel
  lumen so that the arterial wall does not occlude
  it.

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Slide 31.

• Then push the vacuum tube completely into the
  holder after changing your grip to fix the needle
  and ear between finger and thumb.

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Slide 33.

• Cardiac puncture is the simplest route for
  exsanguination. The animal must be anesthetized.
  Lay it on its back and locate the apex beat of
  the heart with your finger tip on the left hand
  side of the chest.

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Slide 34.

• We also use 10 ml vacuum tubes for this
  procedure. More than 100 ml can be collected from
  a 4 kg rabbit

• Put the needle tip where you felt the heart beat.
  Push it between the ribs pointing it in the
  direction of the right shoulder. When the needle
  reaches the heart - a distance of 1-3 cm - you
  feel and see the beat through the needle. If
  blood does not flow try withdrawing the needle a
  few mm. When exsanguination has been completed
  make sure the rabbit is dead before disposing of
  the carcass.

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Remember..

• We have tried to show you a number of ways of
  handling rabbits in the laboratory. Careful and
  thoughtful handling of the animal reduces stress
  and fear. Animals that are unafraid respond
  easily and allow for better experimental
  technique.
• Never forget that the laboratory animal is a
  living creature with the ability to feel both
  pain and fear.