Domestic animals' fear of humans and its effect on their welfare

Abstract

Many studies on pigs, poultry, and dairy cattle have shown that rough or aversive handling of farm animals by people can substantially reduce the animals' productivity and welfare. Some of this effect occurs because the animals become afraid, either of people in general, or of specific individuals as a result of aversive handling. In this paper, we review a number of studies showing that farm animals handled roughly or aversively learn to associate the handling with people, and that this learned fear of people can have marked effects on production. The ability to recognize individual people has now been shown indisputably for many species of farm animals, although under some circumstances, animals do not behave differently to different people. Animals' learned fear of individual people can markedly affect their productivity. For example, in dairy cattle, the presence of an aversive handler during milking can reduce milk yield and substantially increase residual milk. Pigs appear to use multiple cues to distinguish people, although visual cues are clearly important. Cows can readily learn to distinguish between people wearing different colour clothes, but it is more difficult for them to distinguish between people wearing the same colour. Furthermore, cows' responses to people change markedly when clothing colour is changed, although this does not seem to be true for poultry. However, animals' responses to people can be affected by the context. For example, cattle's learned responses to individuals can be strongly affected by the place they are in. We finish with some suggestions as to how these results can be used to reduce fear in farm animals.