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10. Contagious Mastitis


Dry cow Therapy (4)

  1. “Dry Cow Therapy” (DCT) refers to a long-acting antibiotic intramammary infusion administered after the last milking of a lactation, and therefore immediately before her “dry period.”  The dry period is usually about 2 months long and therefore DCT starts when the cow is approximately 7 months pregnant.  
  2. Dairies that have successfully controlled mastitis by proper management might only use antibiotic dry cow treatments for those select cows that appear to be subclinically infected with mastitis pathogens, or use selective therapy in combination with internal teat sealants.  
  3. Dairy farms with high rates of subclinical and clinical mastitis in early lactation should routinely administer an antibiotic dry cow treatment to all their cattle at drying off.


The next step is to determine what antibiotic will likely be effective against the strains of  Staphylococcus aureus and Streptococcus agalactiae that you have circulating in your herd.  We call this profile of antibiotic resistance an ’antibiogram,’ and it can be used for selecting the type of antibiotics that are most likely to be effective.   We want to give strong preference to the older antibiotic products that are approved for use in lactating dairy cattle, that do not interfere with antibiotics commonly used for human medicine, and yet should be effective in killing the bacterial strains prevalent in your herd.  This will help preserve the efficacy of antibiotics for the future.

The good news is that you can eliminate these two pathogens from your herd, and with proper management and biosecurity programs, you can keep these pathogens out of your herd.  


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