Continuous Exposure to an Aversive Mixture: A Means of Maintaining Aversion in Sheep Averted to <em>Geigeria ornativa </em>O. Hoffm. (Vermeerbos) - An Assessment

Establishing aversion to Geigeria ornativa only lasts for some time, after which the induced aversion disappears and sheep start eating G. ornativa again. This behavior is aggravated by the social influence of non-averted sheep in mixed grazing situations. Exposing sheep continuously to a so-called “aversive mixture”, containing an aversive substance (lithium chloride) and the sensory characteristics of the plant (hexane extract of G. ornativa) mixed with a tasty meal (maize meal), following an initial aversion treatment, resulted in sustained aversion to G. ornativa in the field. This method proved to be applicable to mixed grazing situations with averted and non-averted sheep grazing together on a G. ornativa-infested field during the day but separately housed during the night, with averted sheep being exposed to an aversive mixture. It also proved effective when averted sheep separately grazed a G. ornativa-infested field 24 hours a day, while continuously exposed to an aversive mixture presented in a self-feeder. This methodology potentially might also be used to prevent livestock from consuming other non-aversive poisonous plants on a sustained basis.