During twenty years of work on livestock handling and design of restraining devices for animals, I have observed that many people attempt to restrain animals with sheer force instead of using behavioural principles. Improvements in the design of restraining devices enhances animal welfare and will reduce stress and injuries. A series of surveys conducted by the author showed that changing the design of a squeeze chute would reduce injuries to cattle (Grandin 1975), but there is still a great need to improve squeeze chutes that are used on larger feedlots and ranches. Under the best conditions, cattle can become bruised or injured in a conventional squeeze chute. A survey of seven major feedlots by Brown et al (1981) indicated that in five of the feedlots 1.6% to 7.8% of the animals were bruised. Even though bruises would heal by marketing time, pain and trauma may reduce weight gain. Cattle can become asphyxiated by excessive pressure on the carotid arteries. In a standard hydraulic stanchion squeeze chute used in most commercial feedyards an inexperienced operator can cause 2% of the cattle to collapse from pressure on the carotid arteries (Grandin 1980). A collapsed animal will die if the operator fails to release it immediately. Excessive hydraulic pressure can cause severe injuries. The animal's diaphragm can be ruptured (Fulton, R. 1973 personal communication). Excessive pressure can break the pelvis (Miles, D. 1992 personal communication). The author has also observed that excessive squeeze pressure can cause a significant reduction in weight gain. Good management can prevent many of these problems but there is still a great need for improved restraint devices for use on ranches and feedlots. I did not realize how poor existing chutes in feedlots were until I developed restraint devices for calf and beef slaughter plants.
Over the years I have designed several different types of cattle restraint devices for use in meat packing plants. During the course of developing these devices I have learned that the use of behavioural principles will keep both cattle and pigs calm. Many of these ideas could be incorporated into new designs for cattle restraining devices for the ranch farm or feedlot.
Ewbank et al.,(1992) found a high correlation between cortisol levels and handling problems in the stunning box. Use of a poorly designed head restraint device which greatly increased behavioural agitation and the time required to restrain the animal resulted in cortisol levels jumping from 24 to 51 (ng ml)-1. In the worst case the level increased to 96 (ng ml)-1.
Cattle slaughtered in a badly designed restraining pen that turned them upside down had average values of 93(ng ml)-1 (Dunn,1990).