News & Advice

Dairy Antibiogram

Nov 1, 2019 | Dairy, Dairy Animal Health & Welfare

With an increasing focus on better use of antibiotics, knowledge of the resistance status of the common mastitis pathogens in your herd is important. It helps you and your Vet when making decisions about lactating cow mastitis treatments and dry cow antibiotic selection. 
The Antibiogram allows early detection of emerging resistance on a farm, hence allowing changes in treatment approaches if required. Additionally, individual farms can be benchmarked against what is happening nationally in terms of antibiotic resistance. 
More than 10% of farms nationally have now been tested. What this has identified is that more than 30% of farms have evidence of elevated penicillin resistance amongst the  Staph aureus isolates, and a 40% proportion of farms have  Strep uberis isolates that have reduced sensitivity to injectable mastitis antibiotics that contain cloxacillin. 
For an individual herd, the results allow for more focused use of antibiotics, with many farms being able to use appropriate narrow spectrum antibiotics for mastitis treatment throughout the year. Conversely, there are a number of farms who have had to change away from injectable antibiotic for mastitis treatment. 
The Dairy Antibiogram tests the antibiotic sensitivity of multiple isolates of  Staphylococcus aureus  and  Streptococcus uberis  gathered from a bulk tank sample. Using a bulk tank milk sample enables multiple bacteria to be tested and does not require sampling and culture of individual quarters across the herd, which was the way we historically had to gather this information. The test can easily be ordered and does not require any sampling by herd owners. 
Having the Dairy Antibiogram information at the time of your milk quality consult allows your vet to make more precise decisions about the approach to treating both clinical mastitis in your herd and selecting the best approach to drying off. If you have not ordered an Antibiogram test for your herd, talk to your Vet to arrange this important step in taking control of antibiotic resistance in your herd. 

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