Abstract: Dairy cow breast health is directly related to the production performance of dairy cows and the benefits of pasture. How to effectively prevent the occurrence of mastitis in dairy cattle is the top priority of the ranch. The dry milk period is an important stage for dairy cows to recover their mammary gland function,which is of great significance to prevent the occurrence of postpartum mastitis. In this paper,635 cows were divided into groups for one year,and the incidence of mastitis and milk production were observed in 90 days after delivery. Through data analysis,it was found that the positive rate of somatic cells at 7 days after delivery was reduced by 28.58% when the cows were dried with antibiotics and nipple sealer in the dry milk period compared with the dry milk with antibiotics alone. The incidence rate of clinical mastitis decreased by 35.40% at 60 days postpartum and 41.32% at 90 days postpartum.There was no significant difference in milk yield between the groups （P > 0.05）.

Key words: cow, dry period, bovine mastitis, keratin suppository, teat sealant