Feed a complete diet containing enough protein, energy and trace elements. This is especially true for lactating cows. Cattle should neither be malnourished nor obese. In the third trimester of pregnancy, limit milking times, feed high-quality forage and avoid feeding fermented silage. Sodium propionate can be given before and after delivery, once 120g, twice a day, for a total of 10 days, with good preventive effect. In management, stables should be clean, warm in winter and cool in summer, with good air circulation, dry cow beds and comfortable environment. In the third trimester, you should do moderate exercise on a flat playground. In addition, early diagnosis and timely treatment should be made to forestomach diseases, abomasum displacement, obstetric diseases and various poisoning diseases to reduce the occurrence of ketosis.