“Mastitis is still the No. 1 reason we use antibiotics in adult dairy cows,” says Ron Erskine, Michigan State University veterinarian.
Used effectively, they can/will reduce mastitis
Editor’s note: This is the first of a series of articles on mastitis, treatment protocols and new research.
The Food and Drug Administration requires all farms that use prescription antibiotics to have a valid veterinarian/client/patient relationship and written treatment protocols.
Simply meeting that legal requirement is just the first step in proper antibiotic use. More importantly, the protocols are a critical tool in mastitis monitoring and control, reducing residue risks and ultimately, cow and herd health, says Ron Erskine, a veterinarian and milk-quality specialist at Michigan State University.
"You really need a comprehensive plan. Mastitis is still the No. 1 reason we use antibiotics in adult dairy cows," he says. "Plus, there are a lot of costs to mastitis—milk losses, drugs, labor, relapses—even embryo losses and reproductive issues.
"First and foremost, treatment protocols must be set up with your veterinarian," Erskine says. The protocols should include all the little things, such as cow identification, what defines a clinical case of mastitis that requires treatment, cleaning of the teat prior to infusion, what to do if the case is a relapse of a prior infection, the recording of the treatment and milk withhold time.
"Treatment protocols are lot more than what drug to use, how often it is used and at what volume," he says.
Culturing is an important tool in developing your protocol. You should first determine which microorganisms are the main causes of mastitis on your farm. Gram-positive bacteria, such as Streptococcus species, staphylococci or new (not chronic) cases of Staph. aureus, tend to respond to antibiotics better than other pathogens.
"There are two major reasons we get treatment failure," Erskine says.
The first is repeat chronic infections. This is not so much about resistance to the drug being used as changes in the infected quarter that no longer allows the drug to reach the bug, he says.
The second reason for failure is that some pathogens, such Prototheca, Pseudomonas and fungal infections have very little chance of treatment success. Other pathogens, such as E. coli, might have already resolved themselves and be on the way to self cure.
Culturing isn’t fool-proof. Some 30% of cultures won’t isolate any organism. And contaminated samples will only confuse the issue. "But culturing can help identify which cows to treat and which are not likely to respond to antibiotics," Erskine says.
Protocols should also identify who in the parlor makes the treatment decision and who actually treats the cows. Key to all of this is worker training—and retraining. "Protocol drift is a real problem, and retraining at least a couple of times each year is important," Erskine says.
"And that assumes there is no turnover," he says. Some dairies have 20% to 30% annual turnover, so protocols are worthless if new employees aren’t trained in their use.
Once protocols are established, monitoring results is the only way to know if protocols are being followed. There are several ways to validate protocols.
- March 2014