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This will help you avoid injury and contamination as you take the horse’s blood. You want to protect yourself from the needle. It’s a good idea to also wear protective eyewear, but this isn’t necessary. Put your horse into its stall or take it somewhere it's comfortable, such as where you groom it. Then, use a halter and a rope to keep your horse in place. You can also ask a partner to help you keep the horse calm and under control. Use clippers to cut the horse’s coat short over the site of the blood draw. This will make it easier for you to clean the site and see the vein to insert the needle.  This step is optional, but it can be helpful. You don’t need to remove a large amount of hair. A square that is 3 by 3 inches (7.6 by 7.6 cm) should be sufficient. You may not need to trim the hair if it’s already very short.

Summary:
Wear long-sleeved clothing, closed-toe shoes, and gloves. Tie up your horse. Trim the hair on your horse’s neck if necessary.