Where to Start When Diagnosing Mastitis Problems
There are many preventative measures dairy producers can take to limit
poor milk quality on their dairy operations. Even with preventative
measures in place, there still may be the occasional incidence of
mastitis. Just as a reminder, mastitis is defined as an inflammation of
the udder caused by an infection in the mammary tissue, usually caused
by bacteria but can be caused by many different p a t h o g e n i c o r
g a n i s m s . When poor milk quality becomes a concern, it may be
hard to know where to start. Penn State Veterinary Science Extension
and Outreach has developed a new “How-To’s” section of their website
(http://vetextension.psu.edu/howto/) designed to answer some more
commonly asked questions. One such how-to is “How to Diagnose a
Mastitis Problem” written by Hannah McHenry and Dr. Bhushan Jayarao.
This how-to provides four simple steps to diagnose a mastitis problem
that may exist on any dairy operation.
1. Suspect mastitis is the problem
Before diagnosing a mastitis problem, the signs for a mastitis problem
should exist. The simplest detection of mastitis is the appearance of
clinical signs. Clinical signs of mastitis may be a variety of symptoms
including: clumpy looking milk, fever, red or swollen udder, decrease
in food intake and/or milk production, dehydration and in severe cases
even death. Occasionally clinical cases may not appear, but mastitis
still may be a problem. Monitoring Somatic Cell Counts (SCC), which
measure the number of white blood cells in the milk, can be used to
determine the presence of sub-clinical infections in dairy herds.
Generally SCC above 200,000 cells/ml indicates a mastitis problem in
the herd or for a particular group of cows. Since milk from clinically
infected cows cannot be sold, and sub-clinical cows produce less milk,
there will be a decrease in production (and profit on the farm). To
correct this, the infection needs to be rid from the mammary tissue so
it may regain milk production capabilities.
2. Identify the problem organism
Now that mastitis has been identified as the problem, it is critical to
know what organism is causing the infection. A good place to start is
with a culture of the bulk tank. This will give you information
regarding what organism(s) are present in the herd. The important part
of this step is determining if the organism is contagious or
environmental. Contagious organisms (including Streptococcus agalactia
and Staphylococcus aureus) can be transmitted from cow to cow usually
during milking. Environmental organisms (including Coliforms,
Streptococcus (non--agalactia), Staphylococcus (nonaureus)) generally
are a result of the cow’s environment (stalls, pasture, exercise lot,
etc.). There are different approaches to controlling mastitis
infections from contagious organisms than from environmental organisms.
3A. Control Contagious Mastitis Infections
Since these types of infections can be passed from cow to cow,
identifying and isolated infected cows is critical. They should be
milked separate or at least last so they do not infect other cows and
their milk does not enter the bulk tank. Often, newly purchase cows may
bring mastitis infections into the heard, so isolating them initially
may prevent spreading of possible infections. With contagious mastitis
infections, it is important to milk cows out more often, since milk is
the growth medium for the bacteria. Also be sure to cover whole teats
with pre and post dip, and make sure the teats are clean. It may also
be necessary to treat the infected quarter with an antibiotic depending
on the severity of the infection. If the cow is being dried off, a
dry-cow therapy may need to be used to control and prevent infections
during this non-lactating period.
3B. Control Environmental Mastitis Infections
Controls for these infections include using proper milking procedures
and maintaining sanitary milk parlor and housing areas for the cows. Be
sure teats are clean and dry before milking to prevent infection during
the milking process. Pre-dipping teats can help, but should not be the
only control measure taken. Keep milk parlor and housing clean to
discourage bacterial growth. Identify possible problem areas such as
mud holes, manure pits, soiled bedding, etc, to reduce the cows expose
to potential organisms. Depending on the severity of the infection,
infected udders may need to be treated.
Summary
Milk quality can have a significant impact on the amount of saleable
milk produced by a dairy operation. When suspecting a mastitis problem
on a dairy operation, it is important to know what organisms are
present, which cows may be infected, and what changes to milking
protocols and housing sanitation may be required to prevent future
infections. Even though mastitis infections will happen, it is
important to have preventative measures in place to reduce the severity
of the infections and the spread of infections to other cows.
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Robert C. Goodling, Jr., Extension Educator - Dairy, Penn State Extension, Lebanon/Berks Counties
