Essential Oils are great on people, but they also work wonders on our pets. I'll be posting more soon about other animals, but check this out about horses.
To see if a horse will be receptive to a specific oil, hold the bottle up to their nose. Notice what nostril the horse goes to and his reaction to the oil. Horses that like the oil may flare their nostrils, go for the bottle, or try to even nuzzle it right in your hand!
They may also smell with one particular nostril, then go to the other nostril. Watch to see which they do first. If they smell with their left nostril, they may need some Emotional support. If they smell with their right nostril, they probably need some Physical support.
Keep in mind, if your horse smells an oil from the left nostril first for a certain physical condition, then it shows that there is an emotional component that led to the physical issue. The emotional component should be addressed first.