Continued food aversion: Training livestock to avoid eating poisonous plants

Abstract

Animals can be trained to avoid eating specific foods by offering them the food and subsequently administering an emetic to induce nausea. The animal associates the taste of the food with the induced illness and subsequently avoids eating that food. Conditioned food aversion (CFA) is a potential tool to prevent livestock poisoning from palatable and abundant poisonous plants. Cattle have been trained to avoid eating tall larkspur (Delphinium barbeyi L. Huth), a particularly troublesome poisonous plant. However, several factors influence the acquisition and retention of food aversions under field grazing conditions. The age and sex of an animal may influence its ability to form and retain aversions. Novelty of the plant and the intensity of the induced illness determine the strength of the aversion. Social facilitation or peer pressure motivates animals to sample the averted food, and the aversion will extinguish if it is not reinforced. Generalizing the aversion created under controlled conditions in a pen, to a complex vegetation community in the field, may be difftcult for some animals. If these obstacles can be overcome, CFA may be an effective tool to reduce the risk of poisoning on poisonous plant infested rangeland.