No. Giving any equine food treats can lead to nippy, entitled behavior. There are plenty of non-food ways to provide positive reinforcement during training, such as positive words, pets and scratches, breaks and rest. Easy/hard alternation of tasks also provides positive reinforcement. To do this, after completing a new and difficult task, revert to one the donkey has previously performed successfully and easily. Reverting to an easy task when the animal is having difficulty mastering a new task can also provide positive reinforcement.