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Steve Landman, herdsman at Linde Dairy, was skeptical of on-farm mastitis culturing at first. He was uneasy about the extra costs, training and equipment it required. But after working with a veterinarian to implement a culturing system, he has been able to reduce the number of mastitis cases he treats by nearly 60%.
Landman’s family-operated farm is a 1,400-cow herd in a double-20 parallel parlor in White, South Dakota. “From a caregiver point of view, it’s great,” he said. “Instead of giving a broad-spectrum antibiotic and hoping for the best, we are now able to target exactly what we’re after. I wish I would’ve started culturing sooner. Cows are spending far less time in the hospital pen.”
“Culturing broadly identifies the types of pathogens that are affecting your milk quality,” said Linda Tikofsky, DVM, senior associate director of dairy professional veterinary services, Boehringer Ingelheim. “Knowing which pathogens are causing mastitis will help you adjust your treatment protocol and can lead to reduced antibiotic use.”
Culturing can be done by sending milk samples to a lab, but an on-farm system can provide timely results. “With an on-farm culture system, you take a sample and have a basic diagnosis in 18 to 24 hours,” said Dr. Tikofsky. “If you're a remote dairy and have to send that sample off to a lab, you have to account for one day to send it, another day in the lab and one additional day to get results.”
Barriers to implementing on-farm culturing
The main barriers to an on-farm culture system are associated with the cost, time and additional labor needed for a positive return on investment. The initial cost is the incubator, while recurring costs include milk sampling vials, sampling plates and sterile swabs to streak the plate with the milk sample. You’ll also need to find a small, clean area to conduct the lab work.
While the upfront costs of a new system can be intimidating, the potential savings on reduced antibiotic treatments likely outweigh those concerns. According to Penn State Extension, a study found that the cost of treatment and discarded milk associated with clinical mastitis could exceed $350 per cow per year.1 Culturing can help identify mastitis cases where antibiotics aren’t needed. That not only contributes to more judicious use of products, it can also offer significant savings to an operation.
A new process also comes with a learning curve. Culturing involves additional tasks and often requires trained personnel to conduct the lab work as well as to manage and maintain the system. Personnel will have to understand how to properly harvest milk samples, plate those samples, and read and record results accurately. The herd veterinarian can be a great resource for training, as well as regularly reviewing results and protocols.
While training personnel may be an initial challenge, Landman shares how quickly his concerns eased once he implemented the system on his operation.
“From a labor perspective, there are fewer handlings and fewer people to train,” said Landman. “When we talked about culturing years ago, I wasn’t all that keen on the idea of having extra equipment and more people doing specific, sensitive work. But it turns out it’s quite easy. You swab milk on a plate, leave it sit in an incubator for 24 to 48 hours, and the readings are fool-proof.”
Interpreting the results
Culturing provides an overview of what pathogens may be in your herd. Some bacteria may be treatable and respond to antibiotics, while others resolve on their own without treatment. “We look for Gram-positive, Gram-negative and no-growth cases,” said Landman. “That has been a huge game-changer. We’re using significantly fewer antibiotics, and we have a surprisingly high rate of no-growth cases that are curing on their own.”
· Gram-positive environmental bacteria, such as streptococci and staphylococci, are often subclinical for days and even weeks before they result in clinical mastitis. “Subclinical means there are no visible indications that the cow has mastitis,” said Tikofsky. “Yet, bacteria are present and usually create an elevation of the somatic cell count. If clinical Gram-positive mastitis is untreated, the signs may resolve temporarily, but most cases will relapse.” Antibiotics are necessary for these cases to resolve infection.
· Most Gram-negative mastitis cases will self-cure and antibiotic treatment will not alter the outcome.2
· No-growth cases mean no bacteria can be cultured on the plate, indicating that the cow has cleared the infection on her own. Because there are no bacteria, antibiotic treatment is unnecessary.
Culturing and only treating Gram-positive infections can reduce antibiotic use for mastitis by approximately two-thirds.
Implement a system with a veterinarian’s help
To get started with on-farm culturing, work with a veterinarian to implement a system and learn how to interpret the results. Culture-based treatment protocols can help increase treatment success rates and result in using antibiotics judiciously. When you get results and treatment is needed, consider an antibiotic that fights Gram-positive bacteria. Your veterinarian can also work with you to regularly review mastitis cases and ensure you have the right protocols established for proper treatment. For the best results, it is recommended that the farm maintains a relationship with a milk quality lab or veterinarian for confirmatory interpretation of results, periodic lab continuing education and surveillance of contagious pathogens.