LES TRANQUILLISANTS EN ELEVAGE. REVUE CRITIQUE

Although anxiolytic sedatives (meprobamate, diazepoxide) and neuroleptic drugs (phenothiazine, butyrophenone, and thioxanthene derivatives) have different pharmacological and clinical properties, they are commonly grouped under the name 'tranquilizers'. As their main effect is not necessarily a tranquilizing one, such a name is unsuitable and a more neutral term such as 'psycholeptic' should be used. Both categories of drugs have been used in husbandry to increase zootechnical performance (growth, feed efficiency, milk production, egg production), but usually without success, mainly because of the neuroendocrine side effect of neuroleptic drugs, or their interference with food consumption. They have also been used with some success to control stress from transport or environmental conditions and to prevent 'abnormal' behavior patterns such as fighting. The most successful results have come from their use as premedication or immobilization agents. Neuroleptic drugs have been widely employed for these purposes, while anxiolytic sedatives, which have more limited effects, have been only little used. It is not known what factors are responsible for variations in efficacy of the drugs, or their limits of use. The biological and practical effectiveness of such drugs in husbandry must be systematically studied. Methods for doing this are discussed.