There are 3 anatomical sites on the elephants body where blood can be collected:

• One of the ear veins (or arteries for arterial blood sample)

• One of the branches of the saphenous veins (hindlegs)

• Cephalic vein (front legs)

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How to collect a blood sample:

Most elephants can be trained for this procedure using positive reinforcement training. If not trained, standing sedation (or general anesthesia) in case of free ranging elephants) will be required. When alpha-2 agonists are used , vasoconstriction may hinder the access to the ear veins, especially in young calves. Combining alpha-2 agonists with butorphanol may help to increase the filling of these veins.

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When the environmental temperature is low, the ear veins may collapse. Flushing the inner side of the ear with large amounts of warm water (or packing the area with heated bean or rice bags) can increase the filling of these veins.

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The collection site should be clean and dry before blood is collected. 

Ear veins: press firmly on the site where you can see the shape of the vein. Press until you see the vein becoming larger in diameter. Use a small butterfly needle and collect the blood in a vacuum blood tube. If not available, you can use a small needle (23G) and a syringe and empty the syringe in the blood collection tube after removing the needle. To avoid damaging the blood cells (hemolysis), the tube should be filled slowly while flushing the blood carefully against the wall of the tube, that is slightly tilted.

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Saphenous and cephalic veins: these veins are larger in diameter than the ear veins, but covered by a thicker skin. A 19G or 21G needle (preferably connected to a vacuum tube) can be used and should be inserted perpendicular to the skin.