Increasing the population of cattle in Aek Nagali village, especially in hamlet V, really helps the economy of the community, the health of the livestock raised by breeders is important for the animals themselves. It is difficult for veterinarians in Aek Nagali village so that it is the custom of people in the village where when their cows are sick and dying they are immediately slaughtered and the meat is traded. Even though this does not mean that the cow is suitable for consumption or not because there is a cow disease that can be transmitted to humans when eating beef. The purpose of this research is to build an expert system-based system that can provide an overview or decision. The method used is Forward Chaining and Backward Chaining in diagnosing cow disease. The discussion is focused on applying Forward Chaining and Backward Chaining rules and applying them to the system. From the results of research, the backward and forward methods provide information on how to prevent and treat cattle disease so that breeders can know what steps to take.