VMC 221: Veterinary Immunology and Serology (1+1)

RABBIT

 Ear vein

• The rabbit is usually bled with a diagonal cut across the ear vein which opens but does not sever the vein.
• The ear is then stroked gently and the blood collected in a 20 ml container. Various chemicals such as xylene or benzene that increase the blood flow can cause subsequent irritation to the animal and are generally unnecessary.
• The blood flows better from a warm ear, and an infrared lamp is often used to achieve this.
• Since a nervous animal usually yields blood poorly due to peripheral vasoconstriction, the animal is kept relaxed by stroking and soothing.
• Generally 40 ml of blood can be obtained for a month , that leave the rabbit healthy.

Cardiac puncture

• Cardiac puncture is used for animals which for some reason must be put down, and this can yield around 100 ml.
• The animal is first anesthetized and blood is withdrawn from the heart into a 100 ml syringe through a 21 G needle.
• Two persons are required for this procedure, one to hold and restrain the animal and other to withdraw the blood.
• Stand at the animal’s left side and grasp it’s fore paws and ears with the left hand and right hand. Exert gently firm pressure on the animal’s back with right fore arm to prevent kicking or scraping.
• Grasp the fore paws and ears in the left hand and then move the right hand to the back legs while maintaining firm gentle pressure on the animal’s back to prevent struggling.
• Turn the animal on its back with its left side facing the operator. Shave the left side of the chest wall and wipe with 70% alcohol. Palpate the heart beat and locate the area of maximum pulsation, which is usually 3 cm from the midline, midway along the sternum.
• Insert the needle through the space between two ribs and advance it towards the right shoulder.
• Apply slight negative pressure on the plunger. When the heart is entered withdraw the plunger at a moderate steady rate.
• If blood is not obtained on the first attempt, withdraw the needle completely, palpate the chest area again and reenter the chest wall. Care must be taken not to tear the myocardium as this will cause rapid death of animal.
• Remove the needle from the syringe before expelling the blood into a tube, otherwise haemolysis may occur.