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Clinical Mastitis Treatment Decisions

Phil Sears
Dept. of Large Animal Clinical Sciences

Editor’s note: Because of their relevance at this time of the year, this article and the one following are re-runs from an earlier MDR issue.

Trying to diagnose the type of mastitis by its clinical signs is not accurate and often incorrect. Almost anyone can use milk cultures to make current mastitis decisions when choosing the best antibodies for the farm or choosing cows to treat. However, culturing cow’s milk to make future treatment decisions can be misleading.

The next case of clinical mastitis may not be the same organism as the one you just cultured. Using a milk culture to identify the bacteria before treating requires withholding antibiotic treatment for 24 hours before starting antibiotic treatment.

In a study on a large Michigan dairy farm, waiting 24 hours before starting antibiotic treatment did not adversely affect the outcome of the infections or jeopardize the health of the animal. Mastitis episodes did not last longer and fewer days were lost to milk withholding for residue and unsalable milk. This protocol reduced treatments by 80% and saved on treatment costs.

Because of these results, many dairy farms have begun to use local veterinary laboratories or to establish “on-farm” diagnostic testing to culture milk before starting antibiotic treatment. However, before these diagnostic-treatment protocols can be used in dairy farms, someone must be assigned and trained to do diagnostic testing. This person also should be responsible for treating mastitis cases and monitoring cows with mastitis. If clinical mastitis is viewed as a catch-as-you-can by milkers, then this protocol will not be successful.

In this winter’s MSU Extension Dairy Team educational meeting, we explore the choices farmers have in diagnosing clinical mastitis and making treatment decisions. Knowing when not to use antibiotic treatment in some clinical mastitis cases can be just as important as using the correct antibiotic. It could be one of the best economic decisions you can make in animal health care.

The winter meeting presented information about how to:
1) set up an “on-farm laboratory” to culture clinical mastitis;
2) identify major groups of bacteria that cause mastitis;
3) use this information to treat clinical mastitis;
4) use antibiotic susceptibility Minimum Inhibitory Concentration on your farm; and,
5) reduce chronic and recurring clinical mastitis.

You can incorporate this information into your daily routine to make a difference.

Vaccinology: How Vaccines Work
Vaccines have long been considered an important part of disease control for most dairy farms. Understanding how vaccines work (or do not work) is important when developing a vaccine program for the farm. Not all vaccines are equal.

Live vaccines are often made from modified less-active (attenuated) virus. They are useful in causing cells to change in the immune system so they can recognize the disease better and fight the infection. These vaccines are most useful when given in young cattle before the animals have had exposure to the disease. If this is the first time the animal experiences the disease it can respond at a cellular level (cell-mediated immunity) which has some great advantages in protecting the animal. Additional exposure to either live or killed vaccines can additionally boost the immune system by producing more antibodies. These live vaccines are commonly used with viral diseases such as a Bovine Viral Diarrhea Virus.

Killed vaccines, viral or bacterial, are aimed at stimulating antibody production in the animal. These do not produce good cellular responses but produce antibodies that neutralize toxins and reduce damage by the disease. To get the best response, multiple inoculations must be given to achieve adequate antibodies to help the animal fight off the disease.

The Michigan Dairy Review and the Dairy Team join in wishing
Professor Phil Sears all the best as he transitions into retirement at the end of this academic year.


Curent MDR articles

Gas Regulation
Status of greenhouse gas regulation in the federal court.

Air Emissions
on Farms

Measuring emissions from animal operations.

Battling Johne's Disease
How researchers and producers team up to fight Johne's disease.

Algae Poisoning
in Cattle

Detecting and Avoiding Blue Green Algae on Farms.

How's Your Fridge Health?
Storing foods, pharmaceuticals and vaccines at the right tempretures.

Mastitis Treatment Decisions
What to look for in deciding on mastitis treatment.

Vaccinating the Cow Protects the Calf
How vaccination protects two animals for the price of one.

Ten Common Myths about Dairy Foods
Correcting the misconceptions about dairy foods.

Michigan Milk Market
Why there is anticipation for milk price recovery.

Communities of Young Producers
Young dairy producers meet up to learn and share skills and knowledge.

MSU Wins Top Award for Quality Milk
A National Dairy Quality Award Platinum prize for two years in a row.

Dairy Judging Success
MSU excels in national contests.

What's Happening...
Events of the season.