Treating mastitis: Considering the costs of antibiotics and milk discard in dairy cows
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Articles published in scientific journals can be long and complex, so Dr. Pamela Ruegg summarizes research papers published by her team in a new video series on her YouTube channel. These papers discuss economic aspects of mastitis treatment, including the costs of treating mild and moderate cases of mastitis during lactation, the costs of milk discard and antibiotics during treatment, and determining which cows are eligible for selective dry cow therapy at the end of lactation. This is the second article in the series, view the first article here.
Considering treatment costs
There are many costs associated with treating mastitis in dairy cows, but two of the main contributors are the costs of the antibiotics and the cost of discarded milk that is not sold during treatment. Combined, these are called the partial direct costs. Juliana Leite de Campos, then a graduate student with Dr. Ruegg, evaluated over 20,000 cases of mastitis that occurred on 37 dairy farms in a year. The resulting paper was called Variation in partial direct costs of treating clinical mastitis among 37 Wisconsin dairy farms, and was published in the Journal of Dairy Science in 2023. Dr. Ruegg explains three key takeaways from this paper:
1. Discarded milk is the biggest expense in mastitis treatment
The researchers found that the average partial direct costs to treat a case of mastitis were $192, with a wide range of $118 to $337. The largest cost, about 87%, was from discarded milk, and the remaining 13% was the cost of the drugs. Today, cows are highly productive and produce more milk than in past decades. This means that treating a case of mastitis is both an animal health decision and an economic decision.
Cows that produce more milk (and therefore have more milk discarded during treatment) are more expensive to treat than those that produce less milk and have less to discard. For example, the researchers found that cows producing 100 lbs. of milk per day cost about $174 to treat, but cows producing 50 lbs. per day cost only $62 to treat.
2. Some cows cost more to treat than others
Older, or higher parity cows, generally cost more to treat because they produce more milk than younger cows. The researchers found that cows in their third or greater lactation cost $196 per case, while cows in their first lactation cost $163 to treat.
Recurrent cases of mastitis cost less to treat than a first case of mastitis during a lactation. This is because cows that have a second or third case of mastitis during lactation often have a decreased milk yield due to infections and therefore have less milk discard.
Finally, treatment costs varied depending on the stage of lactation. For cows in peak lactation, about 60 to 120 days in milk, the partial direct cost of treatment was higher since milk yield was greatest.
3. The minimum label duration saves money
While farmers can’t always control which cows get mastitis, they do control the antibiotic treatment duration they use. The researchers found that many farmers treated for the maximum duration allowed, even though this is not associated with improved treatment outcomes.
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The study showed that farmers could save about $65 per cow by treating for the minimum label duration. While this seems like a small amount, the savings become significant when considering the entire herd. In a 1,000-cow dairy with 333 cases of mastitis per year, farms could save $21,645 on the costs of antibiotics and milk discard.
Choosing which cows to treat and for how long can be a complex decision on dairy farms. Work with your veterinarian to review treatment protocols and determine the specific scenarios when using longer treatment durations makes sense. For additional information about selecting treatment duration, watch the video. For other mastitis resources, visit Dr. Ruegg’s website or view the complete video series.