New aspects of the use of tranquillizers in animal husbandry, with particular reference to pigs

Tranquillizers have been used in animal husbandry to inorease production, to control stress from transport or herding together or to prevent abnormal behaviour patterns, such as fighting. Neuroleptic drugs (phenothiazine derivatives, reserpine and butyrophenones) have been widely used for these purposes, while anxiolytic sedatives (meprobamate and benzodiazepines), which have more limited effects, have only been little used. In view of the lack of carefully designed experimental studies it is not possible to determine the factors responsible for variations in the effects of the drugs. The effectiveness of these substances from the biological and practical points of view has therefore been systematically analysed and some examples of their present and possible future applications are given.