While the term bull refers to the male of several species of livestock (elephant, water buffalo and cattle) this article will deal specifically with the cattle industry. The National Traumatic Occupational Fatalities (NTOF) surveillance system in the United States, based on death certificates and maintained by the National Institute for Occupational Safety and Health (NIOSH), identified 199 fatalities from 1980 to 1992 associated with the agricultural production industry and inflicted by livestock. Of these, about 46% (92) were directly attributed to beef and dairy bull handling.
Cattle raisers have for centuries used castration of male animals as a means of producing docile males. Castrated males are generally passive, indicating that hormones (largely testosterone) are related to aggressive behaviour. Some cultures place high value on the fighting character of bulls, which is utilized in sports and social events. In this case, certain bloodlines are bred to maintain and enhance these fighting characteristics. In the United States, demand has increased for bulls used in rodeos as these entertainment events have increased in popularity. In Spain, Portugal, parts of France, Mexico and parts of South America, bullfighting has been popular for centuries. (See the article “Bullfighting and rodeos” in the chapter Entertainment and the Arts.)
The cattle industry can be divided into two major categories—dairy and beef—with some dual-purpose breeds. Most commercial beef operations purchase bulls from pure-bred producers, while dairy operations have moved more toward artificial insemination (AI). Thus, the pure-bred producer generally raises the bulls and then sells them when they are of breeding age (2 to 3 years of age). There are three systems of mating currently used in the cattle industry. Pasture mating allows bull to run with the herd and breed cows as they come into oestrus (heat). This can be for the entire year (historically) or for a specific breeding season. If specific breeding seasons are utilized, this necessitates separating the bull from the herd for periods of time. Hand mating keeps the bull isolated from the cows, except when a cow in oestrus is brought to the bull for mating. Generally, only a single mating is allowed, with the cow being removed after service. Finally, AI is the process of using proven sires, through the use of frozen semen, to be bred to many cows by AI technicians or the producer. This has the advantage of not having a bull at the ranch, which is a reduction of risk for the producer. However, there is still potential for human-animal interaction at the point of semen collection.
When a bull is removed from the herd for hand mating or kept isolated from the herd to establish a breeding season, he may become aggressive when he detects a cow in oestrus. Since he cannot respond naturally through mating, this can lead to the “mean bull” complex, which is an example of abnormal behaviour in bulls. Typical antagonistic or combative behaviour of bulls includes pawing the ground and bellowing. Furthermore, disposition often deteriorates with age. Old breeding stock can be cantankerous, deceptive, unpredictable and large enough to be dangerous.
To ensure movement of animals through facilities, chutes should be curved so that the end cannot be seen when first entering, and the corral should be designed with a gap to the left or right so that animals do not sense that they are trapped. Putting rubber bumpers on metal items which create a loud noise when they close can help lessen the noise and reduce stress to the animal. Ideally, facilities should maximize the reduction of hazards due to physical contact between the bull and humans through use of barriers, overhead walkways and gates that can be manipulated from outside the enclosure. Animals are less likely to balk in chutes built with solid walls instead of fencing materials, since they would not be distracted by movement outside the chutes. Alleyways and chutes should be large enough so the animals can move through them, but not so wide they can turn around.
Guidelines for Handling
Male animals should be considered potentially dangerous at all times. When bulls are kept for breeding, injuries can be avoided by having adequate bull-confinement and restraint facilities. Extreme caution should be practised when handling male animals. Bulls may not purposefully hurt people, but their size and bulk make them potentially dangerous. All pens, chutes, gates, fences and loading ramps should be strong and work properly. Proper equipment and facilities are necessary to assure safety. Ideally, when working with bulls, having the handler physically separated from contact with the bull (outside the area and protected by chutes, walls, barriers and so on) greatly reduces the risk of injury. When handlers are with the animal, escape passages should be provided to allow handlers to escape from animals in an emergency. Animals should not be prodded when they have no place to go. Handlers should stay clear of animals that are frightened or “spooked” and be extra careful around strange animals. Solid wall chutes, instead of fencing, will lower the number of animals that balk in the chute. Since bulls see colours as different shades of black and white, facilities should be painted all in the same colour. Properly designed treatment stalls and appropriate animal-restraint equipment and facilities can reduce injuries during animal examination, medication, hoof trimming, dehorning and hand mating.
People who work with animals recognize that animals can communicate despite being unable to speak. Handlers should be sensitive to warnings such as raised or pinned ears, raised tail, pawing the ground and bellowing. General information and guidelines for working with bulls are provided in the checklist and article on animal behaviour in this chapter.
Handlers should also be concerned with zoonotic diseases. A livestock handler can contract zoonotic illnesses by handling an infected animal or animal products (hides), ingesting animal products (milk, undercooked meat) and disposing of infected tissues. Leptospirosis, rabies, brucellosis (undulant fever in humans), salmonellosis and ringworm are especially important. Tuberculosis, anthrax, Q fever and tularaemia are other illness that should be of concern. To reduce exposure to disease, basic hygiene and sanitation practices should be used, which include prompt treatment or proper disposal of infected animals, adequate disposal of infected tissues, proper cleaning of contaminated sites and proper use of personal protective equipment.
The most sanitary method of carcass disposal is burning it at the site of death, to avoid contamination of the surrounding ground. A hole of appropriate size should be dug, flammable materials of sufficient quantity placed inside and the carcass placed on top in order that it can be consumed in its entirety. However, the most common method of carcass disposal is burial. In this procedure, the carcass should be buried at least 4 feet deep and covered with quicklime in soil that is not susceptible to contamination by drainage and away from flowing streams.