On-Farm Culturing of Mastitis

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Would you like to improve the overall quality of milk produced? Are you concerned about clinical mastitis or are you looking to improve your treatment protocols? Is the SCC of your herd too high? If you answered yes to any of these questions, on-farm milk culturing can be an effective way to improve these things on your operation.

Interested producers should note that the success or failure of an on-farm culturing program is dependent upon the motivations, training and support of personnel involved. However, materials needed are readily available and with proper training a clear advantage of receiving timely culture results can be seen.

All cows suspected to have a case of clinical mastitis should be cultured. According to Keith Sterner, DVM – you only get one shot at culturing, when the cow is first noticed before any therapy has been done. Culturing could prevent the cow from being treated with antibiotics and her milk being discarded. It’s also been said that shipping milk with higher SCC counts, is like having someone embezzle milk from the tank, as high SCC cows have lower milk production.

The real advantage in on-farm culturing is how quickly results can be obtained. Gram-negative organisms can be identified as growth on agar plates in as little as 6 to 8 hours. Common gram-positive organisms will show growth in 24 to 48 hours.

Treatment plans can be implemented as soon as the bacteria are identified. Outsourcing milk samples to a lab can result in costly delays in starting on-farm treatment. Accuracy of diagnosis is generally 80%, although it is by no means perfect or could it be compared to lab culturing, but it does work well for the day-to day- management of mastitis. Producers should be ware that on-farm culturing is not designed to identify clinic mastitis caused by mycoplasma. If you suspect mycoplasma, milk samples should be sent to a laboratory.

Culture results can be used to select treatments and take preventative measures. According to Sterner, if a cow shows gram-negative, generally intramammary therapy will not be effective and systemic supportive therapy would yield better results. A gram-positive has better chances for cure through intramammary treatment, with the exception of staph aureus. Strep agalactia and Staph aureus are often associated with milking time practices and therefore control and prevention measures should be concentrated there.

Anyone looking at on-farm culturing should sit down with their vet and milk quality advisor to develop goals for the program and what they would like to accomplish and what is possible. Then develop a road map on how to get there – who, what when, where and how.

More information on on-farm milk culturing programs can be found online at: www.nmconline.org or by talking with your local veterinarian.