According to the measured results of the accuracy of the disease diagnosis, it was found that our expert system
provided the accuracy of 93.56 % which higher than the previous research. Such as the disease diagnosis in knowledge base system of dairy disease [3] gave the accuracy of 83.40 %. Furthermore, from the evaluation result of system users' satisfaction by dairy cow farmers and animal husbandmen were 4.80 and 4.65 respectively, which were a high value. The accuracy of the disease diagnosis and the users' satisfaction with our expert system, it is caused by; (1) The model of knowledge representation for inference used the efficient factors which resulted in accurate disease diagnosis. The used factors were gender, age range, symptom, symptom significant weight and certainty factor of symptom occurred. (2) The system method used to obtain all symptoms completely which resulted in accurate disease diagnosis. Such as providing the symptom description and images caused the users specified the certainty factor of symptom accurately and questioning additional symptoms of possible disease. (3) Our mobile application has high efficiency and the application usage is easy and convenient.