Mastitis is not a cut-and-dried, “diagnose-treat-repeat” disease. Rather, Linda Tikofsky, DVM, Professional Services Veterinarian for Boehringer Ingelheim Vetmedica, Inc. says it is a multi-factorial disease with a good deal of variation in both its causes and solutions.
“A tremendous amount of research has helped us zero in on the intricacies of mastitis,” says Tikofsky. “We now have fairly good control over the contagious pathogens likes Strep. ag. and Staph. aureus, thanks to improvements in milking technique, dry-cow therapy and teat dipping. It’s the environmental bugs like Strep. spp., E. coli, Klebsiella and coagulase-negative Staph (CNS) that remain our greatest challenge.”
Tikofsky believes the new Pasteurized Milk Ordinance (PMO) somatic cell count (SCC) limit of 400,000 cells/mL has been a positive challenge to dairy producers nationwide. “We used to say, ‘we can’t do this,’ but now we know that we definitely can,” she shares. “Lower SCC levels are a quality benefit to milk processors and exporters, but they also directly benefit producers, who often receive premiums for selling milk at SCC levels lower than 200,000.”
She says on-farm culturing of every case of clinical mastitis has helped many dairies by allowing them to assess whether a case is caused by Gram+ or Gram- organisms, and treat (or not treat) accordingly. If on-farm culturing is not a viable option, most dairy veterinary practices now have in-house milk quality labs that can assist with culturing and diagnostics.
“This information is helpful not just in terms of treatment decisions,” says Tikofsky. “It also helps identify the root of the problem – be it milking technique or bedding issues or nutritional deficiencies – so that management changes can be made.”
In terms of drug selection, Tikofsky says dairy producers and processors are under more pressure than ever to limit the amount of antibiotics used on the farm. “Mastitis is the number-one reason we use on-farm antibiotics,” she says. “The FDA keeps a close eye on this use, and it now is being more carefully scrutinized by consumers as well. People can communicate so freely online today, and there is a lot of information and sometimes misinformation spread by lay people. It is our responsibility to listen to their concerns and ensure that we are using antibiotics on our farms judiciously.”
Diagnostic information and knowledge about how various mastitis pathogens behave play critical roles here, too. Cows with chronic Staph. aureus infections, for example, probably will not be cured regardless of treatment and should be culled. Cows with mild or moderate Gram- infections like E. coli probably are on their way to resolving the infection via their own immune defenses by the time clinical signs become evident. These animals probably are best served with supportive therapy and care versus intramammary antibiotic treatment.
When antibiotic therapy is warranted, Tikofsky says more information is available than ever to target that treatment strategically without over-using antibiotics. She cites a recent, large-scale Cornell University study that compared a one-day intramammary treatment with a first-generation cephalosporin antibiotic (cephapirin) to a five-day treatment with a third-generation cephalosporin (ceftiofur). When possible, a first-generation cephalosporin would be preferable for use in food animal medicine because it would compete less with human medicine.
The Cornell researchers found that Gram+ bacteria responded equally as well to the one-day cephapirin treatment as they did to the five-day ceftiofur treatment. Clinical cure (milk and quarter returning to normal) were not different between the treatments.
“This is good news on many fronts,” says Tikofsky. “From a production standpoint, it means lower treatment costs, a faster return to salable milk, and fewer cows in the hospital pen. And on a larger scale, it could potentially reduce on-farm antibiotic use and reserve higher-level drugs for cases in which they truly are needed.”
To learn more about mastitis prevention and treatment, visit BI-Vetmedica.com/Cattle.
Boehringer Ingelheim Vetmedica, Inc. (St. Joseph, MO) is a subsidiary of Boehringer Ingelheim Corporation, based in Ridgefield, CT, and a member of the Boehringer Ingelheim group of companies.