Animals with a nervous, excitable temperament are more fearful than animals with a calm, placid temperament. Flighty, excitable, sensitive animals such as antelope or Arabian horses are more fearful of new experiences than calm, placid animals such as Hereford cattle or Suffolk sheep. If an excitable animal is frightened during training, it is more likely to develop a fear memory which can interfere with future training. An animal may become so afraid of something such as a horse trailer or a squeeze chute that it may be extremely difficult to train the animal to enter it willingly.
It is extremely important that an animal's first experience with something new, such as a horse trailer or a squeeze chute be as pleasant as possible. A pleasant first experience will help prevent the formation of a fear memory.
Animals with a calm, placid temperament will usually habituate if they are repeatedly made to enter a NON-PAINFUL restraint device. Their cortisol (stress hormone) levels will decline after repeated trials of NON-PAINFUL restraint.
However, the flighty, excitable animal may never habituate. It may become increasingly fearful and more stressed with successive trails. Fear is a very strong stressor.
Horses with a calm, placid temperament can be broken to ride by somewhat forceful methods where they are tied up and have rags and other objects placed on them. The calm, placid animal will habituate as long as no part of the procedure is painful. Animals with a calm temperament learn that what they are being asked to do does not hurt and they gradually get over their initial fear.
The same training method may ruin a sensitive, high strung animal by causing permanent fear memories. Instead of habituating, the animal becomes increasingly more fearful. The situation becomes so scary for the animal, it can not overcome it's fear.
In flighty, excitable animals many problems which occur during training are due to fear. In calm, placid animals fear can also interfere with training, but it is less likely to be the sole cause of a training problem.
All animals are fearful of novel situations. Recognizing fear, working calmly and persistently, and never allowing an animal to become so scared that it panics and hurts itself and/or others is the responsibility of everyone who trains animals on any level.