Jennifer L. Lanier
Colorado State University
Department of Animal Sciences
Fort Collins CO USA 80523-1171
The following article was originally presented at the International Bison Conference in Edmonton, Alberta in August 2000. The conference covered a wide array of bison topics including production, marketing, genetics, history and much more. This article has been reprinted with the permission of the IBC2000 Chairman.
American Bison (Bison bison) handling is often a stressful time for both the animal and its handlers. There is some research regarding "in pasture" bison behavior, but little on behavior during handling. The rationale for low stress handling, other than ethical concerns, can be justified on purely economical grounds. Each animal is worth a fair amount of money, consequently, each injury or death represents a sizable economic loss. In order to reduce injuries to bison and handlers, the bison must remain calm while being handled.
Signs of Fear
As animal handlers we must be able to recognize subtle signs of fear in an animal. It is quite easy to recognize the obvious signs such as running away and climbing out of the single file alley. There is a continuum of fear-based behaviors in bison. Some subtle signs of fear include licking, increased blinking, huddling together, and the lifting of the tail. As the fear level increases these behaviors become amplified and new behaviors emerge: labored breathing (panting), frothing at the mouth, vocalizing, running, goring, sitting down in a squeeze chute, or attempting to escape. The next stage of fear that precedes death is tonic immobility. An animal that lies down inappropriately (during handling) and does not respond to stimuli may be in tonic immobility.
Individual differences may affect the appearance or level of fear. One animal may naturally vocalize more than another animal. Just because an animal vocalizes does not mean he is in a state of fear. Knowing what the signs of fear in bison are and how individuals may differ in their expression of fear will assist the handler to recognize, interpret, and respond appropriately to a fearful animal.
The flight zone is that distance from the animal to a threat (as perceived by the animal) that causes the animal to move away from the threat. If the threat is outside the flight zone but still nearby, and the animal is not cornered, the bison will turn and face the threat. As the threat approaches and reaches the boundary of the flight zone the bison will turn and begin to walk away from the approaching threat. Maintaining a slight amount of pressure on the flight zone is effective in maintaining animal movement. However, too much pressure and the animal will run in order to distance himself from the threat. The optimal position of the handler is at the edge of the flight zone. Knowledge of the use of the flight zone is invaluable for handling animals in a low stress manner. Refer to the book "Moving ‘Em: A Guide to Low Stress Animal Handling" by Burt Smith for a complete description and understanding of flight zones.
Initiation of Movement
Initiation of an animal's movement can be accomplished in basically three ways: scare the animal, entice the animal, or use pressure on the flight zone. Most people are fully aware as to how one might scare bison; therefore this technique will not be discussed. Enticing an animal can be done with bribery, such as a food reward or using novelty to attract the bison from point "A" to point "B". A strategically placed bucket or plastic pop bottle can draw in an animal with the animal experiencing very little fear. However, if the bucket suddenly moves (i.e. blows over) the bison will immediately become highly fearful and will make a hasty retreat. Use of a lure (novelty) is most effective in conditions that the bison perceives as normal and routine. This technique does not work on animals that are in a moderate or high state of fear.
Use of the flight zone is a powerful technique that has been extremely successful with bison. Often in a corral situation bison handlers forget the main concept of the flight zone: Work on the edge of the flight zone to control the movement of the animal. In a corral type situation, the handler is deep within the flight zone and thus the main principle has been violated. Fortunately, the principles of using the flight zone to move bison in a corral type setting can still be used. Successful flight zone manipulation in a handling facility relies on the handler remembering that he is deep inside the flight zone and that the animal is most likely in a moderate to high state of fear. Due to this situation, the handler must maintain a quiet and relaxed setting while handling bison. Noise, sudden movements, and distractions such as shadows, dangling chains, etc. will easily trigger bison to enter a high state of fear causing them to crash in to fences, gore other animals and generally attempt to escape the fearful situation. These distractions and sudden stimuli must be kept to a minimum.
Handlers can use a continuum of pressure (noise and visual clues) to move animals in a calm, low fear manner. Begin with the smallest amount of pressure required to cause the animal to move, and incrementally increase the pressure as needed. For example, make a small "shhh-shhh" sound; pause to see if the animal responds to the stimuli. If there is no response after several seconds, make a slightly louder sound. It takes an animal time to process what is being asked of it, especially in a corral setting where the animal is concentrating on several different sounds, movements, and people. Each successive motion or sound made by the handler increases the pressure on the animal and increases the probability that the animal will move. There are three "rules" which apply to moving bison. First, pausing between each successive motion and (or) sound will allow the bison to process and respond according. Second, the use of too much pressure will cause the bison to freeze, backup, jump, bolt or other less desirable action. Third, sudden jerky motions will elicit fear, as these are the same types of movements predators make. Smooth, slow movements are calming and less threatening to prey animals such as bison.
Light, Shadows, and Behavior
Lighting can be a critical factor in the successful handling of animals. Flighty animals such as bison are extremely sensitive to the effects of lighting. By controlling the position and intensity of light, the handler can reduce anxiety and induce bison to work calmly through a handling facility. Most animals prefer to go from a dark area into a well-lit area. Once inside a dark area, most animals are more relaxed than if they were in a bright area. Shadows are a form of contrasts commonly found in handling facilities that are very effective in stopping all animal movement. If a bison cannot see where to go, or if a shadow causes the appearance of a hole, barrier, or the like, the bison will not move forward. Diffuse light reduces shadows and provides a well lit, relatively distortion free facility. An indoor facility can create diffuse lighting with the use of skylights, by opening doors, and by adding windows. Outdoor facilities are often at their best during overcast days. The handler should walk through all facilities at bison eye level at the beginning of every handling session, this includes after lunch.
Solid Sides and Solid Tops
Bison are generally comfortable and relaxed in dark areas. The use of solid sides and tops can greatly reduce the level of fear in bison during handling. Calm bison do not jump, thrash around, slam into fences, or lie down and die from fear. If an animal cannot see a place to escape through, they are less likely to attempt an escape. Conversion of an existing open facility to a solid sided facility can be achieved with minimal expense and materials. Cardboard can be used to temporarily experiment with position to create the desired effect. Attaching strips (approx. 6-10 inches wide) of cardboard at a 45-degree angle to the outside of the bars on the squeeze chute will prevent bison from seeing outside of the chute. This 45-degree angle will also enable the handlers and veterinarians to have access to the animal. It is important that the junction of the bar and cardboard be pointing towards the head of the squeeze chute. Check the position, and width of the cardboard from inside the chute, before working animals. If the cardboard prevents light from entering the chute and you cannot see outside of the chute then the placement and width of the cardboard is correct.
The critical areas for solid sides and tops are in those areas where people are inside the animal's flight zone or where the level of fear in a bison affects their behavior. The squeeze chute and the immediate area preceding the chute are such critical areas.
Bison are herd animals and prefer to be with herd mates rather than being alone. A solitary animal is prone to "aggressive fear-based" behavior. Often these animals are said to "be on the fight". Charging, pawing, head shaking, as well as running, escape attempts, and laying down and dying by solitary animals, are due to fear. Bison are not comfortable being lined up nose to tail as are cattle. Bison are calmer if held as a group and then moved from the group directly into the squeeze chute.
Holding areas should never be filled more than 1/3 full regardless of the size of the pen. This reduces stress and intra-herd conflicts, which often result in goring. Bison held in close confinement (pens, trailers, etc.), should be held with similar bison. Sick animals should be separated from healthy bison. Males and females should be separated, as should juveniles from adults. Bison from different herds should not be mixed.
Training bison for routine husbandry procedures reduces stress. Training is an effective low cost technique for the prevention of death and injuries. Operant conditioning (a style of training) of bison and other flighty animals has been quite successful. Training does not reduce wild-type genetics. Training reduces the inadvertent domestication of bison through the reduction of the wild-type animals killing themselves by running into fences and goring one another. Training bison to move into, through, and to be locked into a facility are critical, regardless of the size of the herd.
Bison present a unique management situation. The greatest facilities can become completely useless without a proactive handler who stops to check the facility for distractions such as shadows, contrasts, litter, and dangling objects like string and chains before working animals. These handlers know to listen to their animals and to investigate areas where bison are balking, and not to force them through without attempting to correct the situation. Good handlers can work animals in poor facilities, but poor handlers cannot calmly work animals in the best of facilities.