You MUST determine which organisms are causing your mastitis. Your veterinarian can help you collect aseptic milk samples from suspect cows. Do not take samples from cows that have been recently treated. Check to see if Nebraska has a diagnostic lab that can run the samples and help you determine what organisms are causing the mastitis.
Mycoplasma, yeasts, gram negative bacteria (e.g., E. coli), and Staphylococcus aureus are common mastitis agents that do not respond to antibiotic treatments. Control measures will depend on which organisms are causing your problems. Streptococcus agalactiae (which today are not very frequent) and environmental streptococci usually respond to treatment if the cow has not had the infection for very long.
Perform a search at the top of the DairyNet site. There are two papers from previous Dairy Day Reports that cover contagious mastitis and environmental mastitis. http://www.livestocktrail.uiuc.edu/dairynet/paperTopic.cfm?TopicID=64
Dick Wallace, DVM, MS, Dairy Extension Veterinarian,
University of Illinois - Illini DairyNET
