Understanding the behavior of Pronghorn antelope makes it possible to habituate and condition them to voluntarily cooperate with veterinary procedures

Temple Grandin, PhD
Department of Animal Science
Colorado State University

Many species of wildlife animals have been successfully conditioned to cooperate with veterinary procedures. This avoids the stress of having to dart an animal to tranquilize it for the procedures.

Highly flighty grazing ruminants such as antelope are the most difficult to train. When they become frightened, they may have an explosive flight reaction and run into fences and injure themselves.

Wildlife specialists have had success hand raising many species of deer, antelope, and other grazing animals. The Pronghorn antelope (Antelope Capridae Americana) is considered one of the most difficult animals to hand rear because it is one of the most flighty species. Pronghorns raised in pens may engage in self destruction behavior when they panic.

The reason why Pronghorns are so flighty is because they live on the plains in small groups. To avoid being eaten by predators, they instantly fluff up (piloerect) the white hair on their rear ends and run from any stimulus that might mean danger. Their behavioral strategy for survival is to run first and then stop and take a look. On the open plains instantly running is a safe strategy because there is nothing to run into. However, in a small pen, it can lead to disastrous injuries. Hunters have reported that the Pronghorn is almost impossible to get close to. It is one of the most vigilant animals.

Successful rearing and training of Pronghorn antelope

A team of students and wildlife specialists at Colorado State University have trained Pronghorn's to voluntarily cooperate with many medical procedures such as injections, blood sampling from the jugular vein, and examination of the body. The two students who did most of the training were Melissa Syndergaard and Lauren Harns. They worked with Dr. Dave Miller from the College of Veterinary Medicine. Many people from both CSU and the U.S. Fish and Wildlife agency worked together to make this project successful. Mark Deesing form Grandin Livestock Handling Systems Inc. built the pens and equipment.

By the time the hand reared antelopes were six months old they were fully trained to a wide variety of medical procedures. On some of the animals, Melissa was able to walk up to them and insert a needle in the jugular vein while the animal was eating a treat. No sedatives were given prior to the procedure. In the rest of this paper, I am going to provide tips and insights into how to prevent a massive explosive flight reaction that would cause an injury.

Principle 1: Always provide an escape path when working with antelope

Even when the animals are fully trained, never break this rule. If something new happens such as a helicopter flying over the pen, the animals will need to have room to run and then stop and look. Four animals were housed in pens that were 30 ft (10 m) long and 8 ft (2.5 m) wide. To obey this rule, always provide an escape path. All people entering the pen MUST stay at one end of the pen. If an animal gets scared, it has room to run to the other end of the pen. If people are standing at both ends of the pen, a frightened animal may crash into a fence because it perceives that its escape path is blocked.

Principle 2: Moving visually large objects is the most frightening

Large objects such as a wheel barrow, ice chest, or card board box are more likely to trigger a panic reaction than a slender object such as a broom or a small object such as a coffee mug. A plywood panel presented so that the antelope sees only the edge is less scary than seeing the full face of the panel. Never walk quickly into the pen with a new large object. Place the object just inside the gate and allow the animals to approach it. Even though antelopes are flighty, they are attracted to novel objects if the object stays still and they are given the opportunity to voluntarily approach. Place some of their favorite food treats on the object. After they are fully habituated to the object you can walk around the pen with it.

Principle 3: Introduce each new procedure in small steps

For more information, see other articles on www.grandin.com or refer to Grandin et al., 1995, Conditioning Nyala (Tragelephus angas) to blood sample in a crate with positive reinforcement, Zoo Biology, Vol. 14: 261-273.

Principle 4: Antelopes do NOT generalize information about frightening things

For the first few months, every time birds flew over the pens in a different direction, the antelopes would fluff up their white butts and run. The first time ice fell off the roof of the shed one of the antelopes jumped and hit the wire mesh ceiling.

If the antelope are accustomed to a red and white ice chest do NOT assume that they will tolerate a solid green ice chest. There brains form specific pictures of SPECIFIC safe large objects. A green ice chest may be perceived as something new. The antelope had become gully habituated to a tractor that was used to move hay. One of the antelopes injured herself when she saw a different tractor. People will generalize and assume a similar tractor is safe. Antelope do not generalize the way people do.

The antelope also failed to make generalizations about veterinary procedures. They had learned that blood sampling from the jugular vein was associated with tasty treats. They have to be conditioned gradually to EVERY NEW PROCEDURE. When a sick animal had to have a subcutaneous injection in a new location was perceived as something frightening and totally new.

Principle 5: Positive experiences do generalize

People were associated with treats and the antelopes had no fear of visitors brought to their pens. They readily approached new people. One animal tried to drink from a pop bottle because he associated it with a baby bottle of condensed milk that was used as a treat for training. The antelope also tolerated people dressed in different clothing. All of the clothing worn by visitors allowed the form of a person to be fully visible. It is likely that a big cape or full length skirt would have been frightening.

Principle 6: Blocking vision will help keep the animals calmer

It was easier to teach the animals to cooperate with medical procedures when they were fed treats inside a plywood box that had solid sides, solid doors on each end, and a solid top. Treats or a baby bottle of milk were fed through a hole in the door. Small doors in the side of the box provided access to different parts of the animal. The box was similar to one used in Grandin et al, 1995. A solid top stops dangerous rearing and jumping. They are less likely to rear if there is a solid panel located about 6 in (16 cm) to 12 in (30 cm) above their head.

Principle 7: The antelope stay calmer when they are with a familiar person whom they trust

Never leave the animals alone in a new place. When they are moved to a new pen a familiar, 'safe' person should be with them. The antelope are able to differentiate between good people and bad people. Medical procedures with treats are perceived as a positive experience but people who have done something scary in the past may have difficulty working with the animals. Previous research with Nyala antelope indicated that the veterinarian who had darted them prior to training was not able to work with the animals after training. The animals readily accepted new people who were not associated with darting.

Principle 8: There are large individual differences between animals

Pronghorn antelope vary greatly in temperament and reactivity to novel stimuli. Some individuals are more likely to have a sudden explosive crash into a fence than others.

The animals who are most reactive are probably the most successful in avoiding predators on an open plain. The less reactive animals are less likely to become injured in captivity and are the ones that may be less likely to avoid predators.

Flighty and calm animals have different strategies when stressed. When a genetically calmer individual is held down by a person he is more likely to struggle and fight. The more reactive individual will often freeze and not resist.

When an untrained animal is held down by a person, the cortisol level will rise from 1.8 ug/dl to almost 6.0 ug/dl at 25 minutes. These are average values. Individual animals will vary greatly. High fear animals will have higher cortisol levels than low fear animals.

When antelope are habituated to blood sampling and learn to voluntarily cooperate cortisol levels will drop dramatically. Blood samples were collected from trained animals every day for five days. On the first day the average cortisol level for eight animals was 4.0 ug/dl. On the fifth day the average for the group dropped to 1.73 ug/dl.

It was interesting to compare the cortisol level in the most flight animal to the calmest animal. Hank, the most flighty individual, was the last animal to accept treats from a person. Bob, the calmest animal, followed people around and was always begging for treats.

Day 1 Sample Day 5 Sample
Bob (calm animal) 2.2 ug/dl 0.3 ug/dl
Hank (Most flight animal) 5.5 ug/dl 3.2 ug/dl

Principle 9: The importance of treats in training

For animals under 6 months of age, a baby bottle filled with evaporated milk was the preferred treat. I observed that when the antelope were sucking on the bottle, they became less reactive to new stimuli. This would make sense out in the wild. If a fawn ran away every time he tried to feed, he would starve. Veterinary procedures were much better tolerated while the animal was sucking. Sucking seemed to act like a sedative. As the animals become older, this effect lessened. Later, dried apple treats and standard operant conditioning were used. To make the association, the treat must be given within 1 second when the animal cooperates and stands still. Operant conditioning instructions are available from many sources. We found that the animals preferred organic dried apples with no preservatives. They refused to eat dried apple pieces from Walmart because they had preservatives.

Principe 10: Provide lots of browse and roughage feed

Even though the antelope had continuous access to food like alfalfa and grass hay, some of the male animals started chewing hair on either themselves or on others. The females did not do this. Hank, the most flighty animal, pulled out large amounts of his own hair. Bob, the calmest animal, did no hair chewing. When weeds and branches were placed in the pens, they immediately started chewing on them. Providing tightly compacted hay in unopened bales reduces hair pulling because the animals had to work hard to get the hay out. They also had loose hay in a horse feeder. The unopened bales provided chewing satisfaction.

One thing that was learned from this is that it was difficult to stop hair pulling after it got started. Providing piles of natural browse plants, such as weeds, sagebrush, and branches, will help prevent this abnormal behavior. The antelopes had great motivation to manipulate things with their mouths. They would chew a glove left on the ground. Plastic sheeting MUST be kept out of reach because they will eat it.

Pronghorns are animals that have to eat huge quantities of low energy feed to maintain body condition in the wild. The spend hours and hours each day eating. In captivity, they were fed much richer feeds and then they had little to occupy their mouths for the rest of the day. They crave mouth activities. They seek novel new branches to chew on each day.

Principle 11: Raise antelope with their own kind to prevent attacks by adult males

To help reduce attacks on humans by adult males, antelope should be housed in groups by two months of age. This will enable the animals to learn that they are antelope. Males reared alone who never interact with other animals are more likely to attack a person when they are mature. This occurs because they think they are people. It is a mistaken identity problem not a tameness issue. For safety, always keep males housed in a pen with a group of animals.

The antelope became much calmer and less reactive to novel stimuli when they were sucking on a bottle. Introducing very young antelope to new animals or new things was facilitated by sucking.

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