April 25, 2017

Develop protocols to reduce mastitis in your herd

Mastitis grading chart and on-farm culturing help create better informed mastitis treatment decisions

by Linda Tikofsky, DVM
Professional Services Veterinarian, Dairy
Boehringer Ingelheim

The dairy industry is conditioned to grab a tube and treat every case of mastitis that comes along. But, in reality, all mastitis cases are not created equal, and treating all cases the same can mean you’re wasting time, milk and money. Since many mastitis cases will self-cure or are caused by pathogens that won’t respond to antibiotic treatment, determining the specific pathogen causing the mastitis before you treat can ensure you choose the most effective treatment.

Target treatment, design protocols and monitor disease

You’ve been taught that prompt attention to the health status of your cows always pays off. When identifying mastitis, it’s important to know how severe a case may be. The mastitis grading chart (Figure 1) is an effective tool to help determine the level, or grade, of mastitis infection.

There are several people involved on a dairy, so it’s important that the milkers, typically the ones to identify mastitis, are able to also identify the severity. The chart serves as a way to develop a consistent protocol and incorporate training for everyone involved on the dairy. By using the chart, milkers can identify the proper steps to take. In a mild or moderate case, they know to take a sample for testing and in a severe case to immediately notify the herdsman. If a farm is able to culture—either on-farm or with their veterinarian—and receive results within 24 hours, they may be able to segregate mild and moderate cases to the hospital pen and delay treatment until they can make a more informed treatment decision.

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The chart also serves as a means of record keeping and disease monitoring on farms. Dairy producers shouldn’t be quick to treat clinical mastitis the same way every time without doing some research on both the health history of the cow and the organism causing mastitis. Is the cow in the first lactation or her eighth? It may not make economic sense to treat a cow that is not productive or that has other chronic conditions. Is she in the early stages of her lactation or late? If late in the lactation period, it may be possible to wait until dry-off to treat. Failure to address the overall health of the cow and not making a conscious decision can result in inappropriate treatments without the desired outcome.

On-farm milk culturing reduces unnecessary treatment

There has been a rise in interest for on-farm milk culturing. It can be an effective option for a farm seeking to make treatment decisions sooner, save money and determine which mastitis-causing pathogens are responsible—especially when convenient local options are unavailable.

On-farm milk culturing is not for every dairy operation. For it to be useful, a farm should have enough cows with mastitis problems in their herd to make the training and equipment economically feasible.  A clean area, separate from animal areas, a dedicated, trained staff member to perform the cultures, and time are also necessary for a successful culture program.  Finally, the herd veterinarian should be involved regularly to review culture results and techniques.  

There are four key reasons for dairy producers to put an on-farm milk culturing system in place:

  1. Better protocols: On-farm culturing at the most basic level allows producers to determine if the pathogens causing the infection are gram-positive or gram-negative, or present at all.  Thirty percent or greater of cows with clinical mastitis have self-cured by the time mastitis symptoms are detected. On-farm culture results can drive decisions to use an intramammary antibiotic, select a specific drug that has greater effectiveness against the specific pathogen, or withhold antibiotic treatment and discard milk until the cow can naturally eliminate the infection.
     
  2. Timeliness: On-farm culturing can give a producer preliminary results within 24 hours. Samples collected and sent to an off-site laboratory may take five to seven days for a diagnosis. Faster results allow the producer to make more immediate and informed treatment decisions and get milk back in the tank faster.
     
  3. Reduced antibiotic use: When treatment protocols are altered to focus on gram-positive mastitis cases, antibiotic use can be greatly reduced, allowing the farmer to combat the problem more selectively and effectively.
     
  4. Cost-effectiveness: With targeted treatment, producers will see a better response to treatment of infections caused by gram-positive pathogens like staphylococci and some environmental streps. A recent study looked at the cost-effectiveness of using on-farm culturing to identify and treat only gram-positive infections. By adopting a selective approach, treatments were reduced by 66 percent and the farm acquired a savings of $53.81 per mastitis case.1 Infections caused by gram-negative pathogens have a high rate of spontaneous cure and most antibiotics have limited efficacy against these pathogens.2 With many cases of mild and moderate mastitis caused by gram-negative pathogens, the cow will clear the infection on her own without antibiotics. Evaluation of numerous research studies have shown 50 to 60 percent of clinical milk samples would earn a “no treatment” decision because they are negative for bacteria or it is a gram-negative pathogen.3

If you believe that on-farm milk culturing may be right for you, several commercially offered systems are available. A local veterinarian or extension employee could be a great resource for finding proper equipment.

The next time a cow shows signs of mastitis, work with your veterinarian to ensure you have protocols in place to properly treat the infection.

 

1Pol M, Bearzi C, Maito J, Chaves J. On-farm culture: characteristics of the test in Proceedings. 49th Ann National Mastitis Council Meet 2009.

2Pyorala SHK, Pyorala EO. Efficacy of parenteral administration of three antimicrobial agents in treatment of clinical mastitis in lactating cows; 487 cases (1989-1995). J Am Vet Med Assoc 1998;212(3):407-412

3Ruegg P, Godden S, Lago A, Bey R, Leslie K. On-farm culturing for better milk quality in Proceedings. Western Dairy Mgt Conf, 2009, 156.