What is environmental
Environmental mastitis is
mastitis caused by bacteria which spread primarily outside of the
milking parlour. This doesn't mean that they don't spread during
milking. Just like with contagious bacteria, infected cows can
contaminate the cluster and spread infection to other cows during
milking. However, unlike contagious bacteria, preventing cow-to-cow
spread during milking will not eliminate environmental mastitis.
This is because parlour management does not tackle spread from the
environment to the cow. To control environmental mastitis, an added
focus on environmental hygiene as well as parlour management is
needed. Parlour management, alongside dry cow antibiotics, has been
effective in reducing contagious mastitis but our control of
environmental mastitis has been much less effective, so that
environmental mastitis now accounts for more than 50% of mastitis
cases in UK cattle. All farms need to include environmental
management in their mastitis control plan.
The two most important
bacteria in this group are E. coli and Strep
uberis. Of the two bacteria, Strep uberis is the one
that spreads more easily during milking, while E. coli is
the one that is most commonly associated with severe toxic
mastitis. However, some strains of E. coli can also be
spread very well during milking and the majority of mastitis caused
by E. coli is mild in nature
Fig 1: Good clean housing
reduces the risk of
Where does environmental mastitis come
A contaminated environment!
E. coli comes from the gut, so anywhere where cow faeces
can come into contact with the udder, will provide a potential
source of coliform mastitis. Bedding is the most important source,
particularly organic bedding where the bacteria can grow and
multiply. However areas around feeding or water troughs are also
risk areas as slurry around these can get splashed onto the udder.
Outside of the udder, Strep uberis is also found
in the intestines but, compared to E. coli, it is much
more commonly found elsewhere on the cow, particularly the skin.
Strep uberis has a fantastic ability to develop outside of
the cow, particularly in straw. Both E. coli and Strep
uberis, particularly the latter, can also cause environmental
mastitis in cows on pasture as they can survive for months in
contaminated wet mud.
Non-organic bedding, such as
sand, doesn't support the growth of either E. coli or
Strep uberis, so the use of such beds can reduce the risk
of mastitis. However, these beds need to be kept clean as there is
more -than enough organic material in a single faecal pat to
support exuberant bacterial growth.
The peak time for infection
with new environmental mastitis-causing bacteria is the dry period.
Infection during the dry period is often inapparent until
the cow develops mastitis after calving. In order to
control environmental mastitis, we have to focus on environmental
management throughout the cow's lactation cycle. Preventing
environmental contamination in the dry cow is just as, if not more
than, important as it is in the milking cow.
Fig 2: Good
clean pasture also reduces the risk of
Fig 3: Acute
coliform mastitis leads to very sick cows
How do you control environmental
Avoid keeping cows in damp
Adequate, clean, dry
bedding is essential - replace daily.
Cubicle comfort and design
- Are the cows using cubicles properly, and not defaecating in
particularly in straw yards.
Avoid overgrazing and
Ensure shade areas (around
trees) are large enough to not become too contaminated
In wet conditions, ensure
cows are in well drained paddocks
Pay particular attention to
management around troughs and feeding areas
Cows should calve in a
clean and dry environment.
Indoors - ensure plenty of
fresh bedding for every cow
Outdoors - choose calving
paddocks carefully, don't overstock
b) Dry cow
Dry cow therapy will reduce
the risk of new environmental infections, particularly in cows with
a history of mastitis or high cell counts (see bulletin 8).
However, the protection against infection provided by dry cow
antibiotics at the end of the dry period is not as good as it is at
the beginning, especially in cows with a dry period of >6 to 10
weeks (depending on the dry cow used). Using internal teat sealant
is the best way of preventing infections of environmental
mastitis. They can be used alone in cows with low cell
counts that don't need an antibiotic, and together with antibiotics
in cows that have high cell counts and are therefore at risk of
being infected at drying off. Internal teat sealants prevent new
infections from the time of insertion, until the cow is milked for
the first time.
In herds with a significant
mastitis problem due to E. coli, the use of a J5 vaccine
has been shown to reduce the incidence and, particularly, the
severity of the disease. Such vaccines are used widely in the US,
but less so in the UK. A combination vaccine which is
effective against mastitis due to E. coli and staphylococci is
currently available in the UK and may be beneficial on some farms.
However such vaccines are only one component of a mastitis control
package, do not control Strep uberis and are no substitute
for good environmental management.
Fig 4: Dirty udders spread
d) Good milking routine
Although environmental bacteria spread outside the parlour, good
milking management will reduce environmental
mastitis. For example, ensuring teats are clean before milking,
foremilking to detect early mastitis cases, keeping teats in good
condition, and reducing impacts by good cup removal technique will
all reduce the level of environmental mastitis, particularly that
caused by Strep uberis. So having environmental mastitis
does not mean that you need to pay less attention to your milking
One important change to the milking routing which can reduce the
spread of environmental mastitis, is adding pre-milking teat
dipping to the protocol (See bulletin 7). There are several
commercial dips available on the market but you must ensure that
you use a dip designed for pre-dipping and allow 30 seconds contact
time before you dry the teats.
e) Good recording of
Proper mastitis records with
good bacteriology are essential to tackling an environmental
mastitis problem. Always take a milk sample from cows with mastitis
before treating them for the first time, freeze it and when you
have a problem you have a selection of samples available to test.
Without good information, individualised targeted control
programmes cannot be developed for your farm.