HOW TO COLLECT BLOOD
Blood is easy collected from the tail - both the coccygeal vein and artery run along the midline of the tail in cattle.
Pull the tail straight up
Find the midline groove about 8 - 12cm from the base of the tail.
You’ll be able to feel the “valley” with your fingers.
The higher up you pull the tail, the easier it will be to find the valley.
The cap of the syringe is pointing to the groove in the above photo.
Insert the needle about 1cm into the groove, perpendicular to the tail.
Pull back gently on the syringe. If you don't see blood, slowly move the needle in and out, or pull out completely and try higher or lower on the tail.
You may feel yourself hit the bone occasionally. This means you are a little too deep - pull back slightly.