First, let's take a moment and look at ourselves, the human. If we pinch the spot right above the bridge of our nose, this is where our olfactory nerve is. The Olfactory Nerve sends messages directly to our limbic system in our brains, which in turn sends messages to our body to react immediately. For example, when we go in for surgery, the anesthesia is delivered through a mask. When we breathe in those synthetic compounds, our limbic system is powerful enough to send signals to our body to knock it out in under 10 seconds.
Now let's take a look at it in horses
In the image above, the CNO (lime green) is called Nervus Terminalis, responsible for sensing pheromones for mating behavior. CNI (Grey) is the Olfactory Nerve, responsible for the horse's sense of smell. Both nerves only rely on smell to relay information directly to the brain and there is no delay in sensory input. So, this information can instantly trigger different behaviors. Have you ever had a smell bring back memories or strike an emotion? This is why. It receives input and signals from the entire body and senses.
Wouldn't it be great if a could just tell you what is wrong? Through zoopharmacognosy, I allow my horses and other animals to (in directly) tell me what is wrong and what they need. Whether to support digestion, behavioral issues or those situations where there is nothing obviously wrong - but they "Ain't Doing Right". Self-selection allows your horse to let you know what they need, in the quantity it needs, and in the way it needs it.
When administered aromatically, we can support our horses' (and our own) respiratory system, hormones, emotions, and more. I personally use doTERRA essential oils for myself and my horses because of their CPTG standards and dedication to quality.