High Prevalence of Subclinical and Clinical Mastitis Caused by Environmental and Minor Pathogens in a Large Dairy Herd in Iran

Abstract

Environmental and minor pathogens seem to be of increasing significance, especially in situations where major contagious pathogens (Streptococcus agalactiae and Staphylococcus aureus) have been controlled using post-milking teat disinfection and dry cow therapy. Herd management practices that successfully control contagious pathogens fail to control coliforms and many streptococcal bacteria. Coagulase-negative staphylococci (CNS) are the most prevalent bacteria isolated in herds using currently recommended control measures and Corynebacterium bovis ( C. bovis) was identified as the cause of up to 20% of all cases of clinical mastitis in some herds.