Mastitis is the inflammation of the mammary gland due to the effects
of infection of the gland by bacterial or mycotic pathogens. The disease
can occur all over the world and may affect all species. It is of greatest
economic importance in the diary industry and is the main cause of loss
in milk production. The bacterial pathogens most commonly responsible for
bovine mastitis are: Staphylococcus aureus, Streptococcus agalactiae, other
streptococci, coliform organisms, Corynebacterium pyogenes and Pseudomonas
aeruginosa. Less commonly, mastitis may be associated with infection of
the gland by Nocardia asteroides, Colostridium perfringens, Mycobacterium
spp., Mycoplasma spp. and yeasts. The major technical factors which cause
the disease are poor milking hygiene, milking machine faults, faulty milking
management, teat injuries and teat sores. Mastitis can be peracute, acute,
sub-acute, and sub- clinical. Even sub-acute cases have reduced milk production.
If mastitis is a problem or there is a high proportion of sub-clinical
cases, veterinary advice should be sought on the control of the disease.
Apart from Streptococcus agalactiae which can be eliminated from a herd,
the organisms causing mastitis are common and widespread and eradication
is impossible. However, with good hygiene and management, mastitis can
be kept well under control by minimising contamination of the teats and
prompt attention to teat injuries, etc. Flies may spread the infection
from teat to teat and fly control may be required.
Clinical signs:
The most significant signs for mastitis is changes in the milk and the
udder. Early in the disease, the affected quarter is inflamed causing heat
and pain. Later, the condition becomes worsen and the inflamed tissues
become fibrous ranging from a few nodules to extensive hardening. In severe
cases, the affected may develop fever, depression and loss of appetite.
Abscesses or gangrene may develop in the affected quarter and milk from
the affected quarter has clots, flakes and pus. In sub-clinical cases,
milk from the affected quarter may become watery (this should not be confused
with the normal watery secretions of non-lactating cows). Most animals
recover but the affected quarter may have extensive fibrous scar tissue
causing permanent cessation of milk secretion.
Treatment:
Antibiotics are used for treating mastitis. The affected quarter is
first stripped out by hand and the outside thoroughly washed and dried.
The teat should be disinfected. The nozzle of the antibiotic tube should
then be gentlely inserted into the teat canal and the antibiotic ointment
be squeezed into the affected quarter. After that, gently close the end
of the teat by hand and massage the udder to make sure that the antibiotic
is properly diffused. The antibiotic should be administered every twelve
hours until the milk has returned to normal and then continue for another
day. Veterinary advice should be sought on the most suitable antibiotic
to use to ensure the effectiveness of the treatment. Milk should be discarded
for three or four days after the treatment finishes and should not be used
for human consumption. In severe cases, injection of antibiotic into the
affected quarter is required.
Control measure:
Because of the widespread of the organisms that cause mastitis, eradicating
the disease is impossible. However, with good hygiene and management, mastitis
can be kept well under control. Flies may spread the disease from teat
to teat. Therefore, fly control may be required.
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