Desensitization is the gradual exposure to a stimulus at a level that doesn’t cause an adverse reaction in an animal.
Counter conditioning is the shift from negative emotional reactions toward positive emotional reactions in presence of a stimulus.
Combining both techniques could look like this:
For example, I’m afraid of spiders. Instead of having direct contact with a big spider, which would lead to screaming, a racing heartbeat, and distress, so I proceed gradually. Someone will point at a tiny spider that I can barely see at the other end of the room and I will get a piece of chocolate. I then have the option to leave the room if I want. We will do the exercise again later bringing the spider just a little closer, or we will use a spider that is a little bigger. Again, giving me chocolate when I succeed. In time, when I see a spider, I will feel good instead of being in distress because I will be looking forward to having chocolate!
When a fear or phobia is overwhelming, it is possible that physiological and psychological reactions are too big to establish a new positive relation. It is often in such situations that we can add pharmacological treatment to enhance conditioning and desensitization. If you think that your animal has such issues, the best person to help is your veterinarian and his team. Don’t hesitate to contact them because they will have tools to help you.