To control mastitis in dairy cattle, National Mastitis Control Program (NMCP) has been conducted in Korea since early 2000s. Nevertheless, mastitis still remains one of the most important disease in dairy cattle in Korea as other countries worldwide. Under the NMCP, a total of 343,090 lactating cows nationwide were tested for mastitis during 2004～June 2010 based on California Mastitis Test (CMT), and 7.8% (26,782/343,090) and 13.8% (47,335/343,090) of the cows tested were infected with clinical and subclinical mastitis, respectively. Relative frequency of 2,058 bacteria isolated from bovine milk samples with somatic cell count of ≥200,000 cells/㎖ during 2006～2010 were analyzed. The most frequently isolated bacteria were Staphylococcus spp. including Staphylococcus aureus, accounting for over 50% of the total number of isolates. The highest frequency was observed for coagulase-negative staphylococci (CNS), followed by Gram negative bacteria (GNB), S. aureus, Streptococcus spp., and Enterococcus spp. Based on the results of recent studies in Korea, the majority of pathogens isolated from subclinical mastitis in dairy cattle in Korea are environmental minor pathogens. Therefore, more attention should be paid to control of environmental pathogens such as CNS, GNB, and Streptococcus uberis in dairy farms in Korea.

ABSTRACT
 유방염의 개요
 국내 젖소에서의 유방염 방제 대책
 국내 젖소에서의 유방염 발생률
 최근 국내 젖소에서의 주요 유방염 원인균 및균종별 분리 빈도
 참고문헌

• 남향미(국립수의과학검역원) | Hyang-Mi Nam (National Veterinary Research and Quarantine Service) Correspondence