Aversion of sheep for handling treatments: Paired-choice studies

Sheep were repeatedly forced to choose among pairs of routine handling treatments to determine if the paired-choice method could be used to measure the relative aversiveness of these treatments. Each sheep was run down a Y-shaped race, and the direction the sheep turned determined which treatment it received. The ranking of the treatments obtained was fully transitive and was, in order of decreasing preference: human contact, physical restraint in the presence of sheep, isolation, capture in isolation, and inversion in isolation. There was a fair degree of consistency across sheep, but differences in preference were found for treatments that were of a similar degree of aversiveness. The method can be used to obtain an ordinal ranking of treatments, but whether an interval-scale measure of the degree of preference can be obtained is uncertain, since choice of the less preferred treatments could result from limitations on the sheep's ability to learn and remember which arm of the race led to which treatment.