“Overuse of antibiotics is a very significant threat to our industry,” said Pamela Ruegg, DVM, Michigan State University as she addressed a crowd of dairy producers at the Great Lakes Regional Dairy Conference in Mt. Pleasant, Michigan. “It’s something that leads into the whole sustainability issue relative to how are we going to maintain our social contract with our consumers. At the same time, we have to ask, ‘How are we going to effectively and freely take care of the animals that we care for?’”

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Freelance Writer
Melissa Hart is a freelance writer based in Michigan.

Ruegg went on to show a survey performed by Cornell University of 1,000 consumers who were asked to rank the threat to their personal health based on antibiotic use on dairy farms.

“The results of this survey showed 70 percent of the consumers perceived a moderate to high threat to their personal health based on our use of antibiotics on dairy farms,” Ruegg said.

Producers believe they are using the correct amount of antibiotics, but in contrast to milk quality, reproductive performance and milk yield, the industry has no key performance indicators for it.

“If you can’t benchmark it, then you have no goals for it and you can’t see where you are with it,” Ruegg said.


Benchmarking allows a way to measure something and see where you are compared to your contemporaries. This is where the defined daily dose (DDD) comes in; the DDD is the adopted measurement for antibiotic protocols and is the number of days an average cow received an antibiotic treatment in a time period. Therefore, 5 DDD per cow per year means the average cow received a labeled dose of an antibiotic for five days in a year. 

Ruegg has performed lots of research on antibiotic use in the Midwest, but if it doesn’t provide a way to improve practices, how beneficial can it be?

With a plan in hand, Ruegg and her colleagues developed an antibiotic benchmarking tool for producers to use in their computer systems. The tool will help farmers measure antibiotic usage in adult cows and pre-weaned calves with the goal of helping the farm’s advisers understand how to use antibiotics responsibly, while maintaining animal welfare.

Following the prompts in the system to identify all events, chores or protocols that are used to record antibiotic usage, farmers can create a report and examine it to make sure their treatment protocols are correct. When they have calculated the DDD per cow per year, they can then compare to validated peer farms. If good record-keeping systems are in place, these reports can generate not only the average DDD for a period of time for the herd, but what each treatment was, how often it was given and where the herd ranked with other herds.

This benchmarking has shown there is great variation in antibiotic usage from farm to farm. It has also shown that mastitis treatment during lactation or at dry-off accounts for most of the doses per cow. This data was collected from 74 farms in three U.S. states. Some farms show zero use, and other farms are as high as 11 DDD per cow per year.

Ruegg said you need to consider three things when evaluating your antibiotic practices.

“One, you can go with your normal protocols. Two, consult with your local vet to go over protocols for mastitis, metritis and pre-weaned calves, or three, you can ask yourself, ‘Do I really need to treat for six days or can I treat for the label duration of three days?’” Ruegg said.

The ultimate goal for any farm is to prevent bacterial diseases so antibiotic usage is not needed. According to Ruegg, producers need to determine incidence of the big five bacterial diseases, and those include clinical mastitis, metritis, BRD, foot diseases, calf diarrhea and pneumonia. Then they need to review the duration of the treatments of mastitis and metritis. And finally, consider selective treatment of non-severe clinical mastitis and selective dry cow treatment.

Ruegg offered producers the option to benchmark their farms by visiting the dairy antibiotic benchmark website.