Electronic copy available at: http://ssrn.com/abstract=1798382
Mastitis in Dairy Cattle in India
By: Dr Kishore T Motwani
Mastitis is multi factorial and a costly problem affecting all milk producing ruminants in
India Unfortunately, there is no simple solution to it. As per 2006 estimates referred in
ICAR’s National Agricultural Innovation Project, the estimated annual loss due to mastitis
alone is nearly Rs16,702 millions.
Mastitis reduces milk yield and alters its composition. The magnitude of these changes
in individual animal varies with the severity and duration of the infection and the
causative microorganisms. Mastitis is almost always caused by bacteria. These
microorganisms produce toxins which directly damage milk-producing tissue of the
mammary gland, and the presence of bacteria initiates inflammation within the mammary
tissue in an attempt to eliminate the invading microorganisms. The inflammation
contributes to decreased milk production and is primarily responsible for the
compositional changes observed in milk from infected quarters and cows. In general,
compositional changes involve an increase in blood components present in milk and a
decrease in normal milk constituents.
Three major factors involved in mastitis are namely: (1) the microorganisms as the
causative agent, (ii) the cow or a buffalo as host, and (iii) the environment, which can
influence the cow / buffalo and the microorganisms.
(1) The Causative Agent:
Over 100 different microorganisms can cause mastitis, which vary greatly in its route by
which they reach the mammary gland and in the nature of the disease they cause. Of
these pathogenic organisms, one can divide it into 2 groups: contagious pathogens and
environmental pathogens The major contagious pathogens are Streptococcus
agalactiae, Staphylococcus aureus, and Mycoplasma spp. which gain entry into
mammary gland through teat canal-with exception of some mycoplasmal infections
whereas, other important bacteria are environmental coliforms like Escherichia coli and
(2) The Host Animal
Cows get udder infection at different ages and stages of the lactation cycle-usually
animals in 4-5th month of lactation being more susceptible(59%) whereas, hind quarters
being more affected(57%) than fore quarters(43%). The immunological status of the
animal also affects the risk for mastitis. During certain stressful periods, e.g. around
calving, the immune functions of the dairy animal are suppressed. This peri-partum and
early lactation period, is also associated with a high susceptibility to udder infections and
mastitis. Other diseases, like different viral infections, which cause immune suppression,
stress of high milk yield or injuries also increase the risk of mastitis .Cows also vary in
their ability to overcome an infection once it has been established and so plays an active
role in the development of mastitis.
bacteria play a role in causing the disease, one can exactly hit it with a vaccine to stop it
from ever becoming a problem."
Excellent progress has been made toward coliform mastitis control with the development
of mutant gram negative vaccines and many attempts are being directed world over
towards development of an effective vaccine for Staphylococcus aureus. To improve the
success rate of vaccination is an ongoing objective of much research world over.
Drug therapy is usually recommended for the elimination of existing intramammary
infections as spontaneous recovery and culling have limited application. Treatment
during lactation is recommended when cows are infected with Strep. agalactiae, when
the herd SCC is greater than 400,000/ ml, and when clinical mastitis is present. Most
cases of subacute clinical mastitis can be treated with an approved intramammary
infusion product preferably containing hydrocortisone in an easy diffusion base .for a
minimum of 3 days accompanied by frequent stripping to remove secretions, bacteria,
and cellular debris. Treatment of subclinical infections using conventional intramammary
infusion during lactation is quite successful against Strep. agalactiae. Chronic Staph.
aureus infections are best treated using a combination of intramammary infusion with
parenteral drug administration containing betalactamse inhibitors to check relapses with
proper teat end sanitization and infusion procedures.