A friend of mine was traveling in the desert alone, and accidentally backed into a Cholla cactus. She was unable to pull the needles out of her leg and had to flag down some campers passing by who helped her remove the needles with a pliers. Most experienced desert travelers recommend carrying a fine tooth plastic comb which can be used to pull out most of the cactus needles. Some of the larger cactus needles may require a pliers or similar tool for removal. Another hazard to watch out for in the desert are venomous creatures such as rattlesnakes, bees, wasps, and stinging insects.
Most trail riders are aware of rattlesnakes and other stinging insects, so use common sense.
If your horse gets bitten by a rattlesnake don't panic, keep your horse quiet and calm and lead your horse back to your vehicle or camp area and contact a veterinarian as soon as possible. Most bites occur during the spring and summer when the weather is warm and the rattlesnakes are most active. Bell boots and splint boots can help protect your horse from snake bites and cactus needles. Bites most often occur on the legs and face area of the horse. Bites on the head can cause considerable swelling.