When a bull is on his home ranch he is calm and peaceful. When confronted with the strange surroundings of a test station, the same bull goes berserk, charging at people. Why does one horse remain calm when a plastic bag blows past him and another one blows up?

Both of these individuals are flighty, high strung animals that become highly fearful when suddenly confronted with a new sight or sound. Animals with a genetically determined flighty disposition are more reactive and more likely to become highly fearful when suddenly put in a new environment or when they experience new sights and sounds.

Experience And Genetics Behavior is determined by genetic factors and experience.

-- Cattle that seldom see people will be wilder and have a larger flight zone than cattle that see people every day.

-- Cattle that are quietly handled will have smaller flight zones and be easier to handle than cattle that have been roughly handled.

-- A horse with a flighty temperament can be gradually trained to tolerate plastic bags, but would be more likely to "spook" if he saw a kite flying which he had not been trained to tolerate.

So how do you determine an animal's genetic temperament when experience has such a large effect? The best way is to subject the animal to a sudden new scary experience. One of the best places to see an animal's true genetic reactivity is in an auction ring. The highly fearful ones will attempt to jump out or crash into the fence.

One rancher told me that when he buys bulls he jumps off the pen fence to startle them. He won't buy those that spook.

The effects of experience will mostly disappear when a horse or bull is startled by a sudden new sight or sound. The tendency to startle or become agitated when forced into a new experience is determined by genetically based fearfulness.

The animal's fearfulness level is the "temperament" that's scored when cattle are rated on a numerical scale for "chute score." The cattle that became highly agitated in the squeeze are the fearful ones. A horse with a flighty, excitable temperament may be calm at home, but may rear, prance or buck the first time he sees and hears plastic pennants used to decorate a fairground.

Fear Mechanisms Fear is a universal emotion that motivates animals to flee predators. Scientific researchers have mapped the fear circuits in the brains of animals. Joseph Ledoux, Center for Neural Science at New York University, discovered that both animals and people can develop permanent fear memories that can never be erased.

A good example would be a horse bashing its head on a trailer the first time it was loaded. This may make him difficult to load for the rest of his life. The fear memory is recorded in the amygdala, a center in the lower brain. Horse trainers need to be very careful to prevent the formation of fear memories, which can interfere with training.

Fear memory problems are most likely to occur in highly flighty, excitable horses and cattle. If a fear memory is formed, a horse may be able to learn to overcome its fear of trailers, but the old fear memory can pop back up when it's least expected. To overcome the fear of hitting its head, the cortex (higher brain centers) must continuously send an override signal to suppress the fear memory.

Fear memories can be made instantly, but it may take months for the horse to learn not to be afraid of the trailer. When training horses, emphasis must be on preventing the formation of fear memories.

Much greater care is needed with high strung, flighty horses then a calm, cold blooded horse. Trainers need to recognize individual differences when training animals.

Training Methods And Genetics A basic principle is that genetically calm animals can be introduced much more rapidly to new experiences than genetically reactive excitable animals. If an excitable animal is forced to do too many new things at once, it may become extremely fearful and won't recover easily.

I dislike rough methods of training horses, but people who use them say they work. One method is tying a young colt to a post and sacking it out by throwing bags, cans, plastic and everything else at it until it stops struggling.

This may work on a genetically placid, calm colt, but will likely ruin a high strung excitable Arab. This is a good example of how experience interacts with genetics. The Arab colt will never habituate; he just remains scared.

Experiments done with pigs at Texas A&M University by Ted Friend vividly show how different animals react to being placed in a tank for swims every day for several days. All the animals were scared the first time and their adrenaline levels skyrocketed.

Over a period of days, the animals divided into two groups. The genetically excitable pigs never habituated and their adrenaline levels remained high. But in the calmer group of pigs, adrenaline levels lowered with each successive swim.

Anyone who trains animals must understand that extremely flighty animals must be gradually introduced to new experiences and not be suddenly forced into them.

Good First Experiences Important For both horses and cattle it's important that their first experiences with something new be good. The horse that "blew up" when it first experienced trotting may always have a tendency to buck or jump when it changes gaits from a walk to a trot.

A fear of the scary experience of starting to trot may be formed. If this horse continues to have trotting problems, changing the saddle so that trotting feels different may help avoid triggering the fear memory.

Research with rats shows the powerful negative effect of a bad first experience. If a rat was shocked the first time it entered a new corridor in a maze, it would never enter that corridor again. However, if it entered the corridor several times without getting a shock, it would still enter the same corridor after it had had a shock.

Likewise, a horse's first experience with a trailer should be a good one and the first experience cattle have in a new corral should be something positive, such as being fed.

If the first experience is negative, the animals may become permanently afraid of trailers or corrals. First experiences make a big impression on prey species animals like cattle and horses.

The paradox about novelty is that it's scary if suddenly thrust on an animal. But, it is attractive if an animal is allowed to voluntarily approach it.

A clip board or box placed in a field or pen will attract both cattle and horses. They'll approach, poke and sniff. But if the wind moves the paper, the animal quickly backs away.

The most excitable, flighty cattle and horses are the ones that will be most attracted to a novel object in their environment, but they will be the first ones to run away if the object moves.

Excitable animals are more aware of their surroundings than calm, placid animals. Many trainers feel that the more spirited (excitable) horses are smarter.

People working with cattle and horses will have an easier time training and working with them if they understand how genetic factors interact with experience. The basic principle is that animals with flighty, excitable genetics must be introduced more gradually to new things than an animal with a calm placid temperament.