Subclinical Bovine Mastitis in Rajasthan

RESULTS AND DISCUSSION

no growth were found in 4 (4.88%) milk samples. Among

Prevalence of subclinical bovine mastitis in animal level

the mixed growth, prevalence of Staph. spp. and Strep.

was recorded as 67.27, 64.55, 63.64 and 74.55 % by

spp. was the most predominant combination with 12.2%

CMT, WST, SFMT and SCC, respectively whereas 39.55,

of prevalence. This was followed by Staph. spp. + E. coli

38.86, 37.95 and 45.23 % by CMT, WST, SFMT and

combination, Strep. spp. + E. coli combination and Staph.

SCC, respectively in the level of quarters, as summarized

spp . + Strep. spp . + E. coli combination with 11%, 6.1%

inTable 1. The figures on both animal wise and quarter

and 3.66% prevalence, respectively.

wise prevalence of SCM based on individual tests closely

On cultural examination the Staph. spp. was found to be

proximated with the observations of Sharma et al . (2004

the chief etiological agent causing SCM. This finding is in

and 2007). However, both lower (Sharma and Sindhu,

agreement with the earlier reports of Sharma and Sindhu

2007; Sharma and Maiti, 2010; Supriya et al. , 2010;

(2007); Sumathi et al . (2008); Sharma and Maiti (2010);

Bachaya et al., 2011; Hegde et al ., 2013) and higher

Harini and sumathi (2011) and Ranjan et al . (2011).The

(Muhammad et al ., 2010) prevalence rates of SCM have

highest incidence of Staph. spp. are closely associated with

been reported in the literature. This large variability of

hygiene. It becomes pathogenic whenever the hygienic

prevalence of SCM found around Jaipur could be due to

conditions of the animal or environment become meager.

prevalence of risk factors e.g., a large proportion of cow

Moreover, the existence of high concentration of Staph.

confined to zero grazing production system, differences in

spp. in milk also indicates the relatively poor quality of

management practices and poor hygienic standards of the

milk, related with unhygienic milking practices as this

dairy environment cum milking conditions. Other factors

pathogen is mainly spread during milking via milkers’

that could influence the prevalence of SCM could be due to

hands [Bradley 2002]. This also might be due to harboring

immune responses, genetic variation in disease resistance

of the organism in the skin, udder and milk of the infected

amongst the breeds, some heritable characteristics

gland which acts as reservoir (Olmsted and Norcross,

such as milk production capacity, teat structure, udder

1992). Davidson (1961) have shown that the ability of

conformation, use of different methods of diagnosing of

Staph. spp. to bind to epithelial cells of the ductile and

subclinical mastitis and the definition of infection, which

alveoli in mammary gland is also an important virulence

is variable according to Mdegela et al. (2005). According

factor.

to IDF criteria, 15.38 % quarters of cows were suffering

Strep. spp. was the second largest mastitogen group

from sub clinical mastitis on account of having somatic

of isolates recovered from our experiment. This was

cell count (SCC) more than 5,00,000 per ml of milk and

in accordance with reports of Sahoo et al ., (2009) and

culturally positive. The prevalence rate of SCM on IDF

Sharma and Maiti (2010). Strep. spp. which is an obligate

criteria was lower than cultural examination or SCC alone.

parasite of the epithelium and tissue of mammary gland,

These findings are in agreement with the observations of

multiplies in the milk and on the mammary epithelial

Tuteja (1993) and Sharma and Kapur (2000), Supriya et

surfaces, generally causing a subacute or chronic

al . (2010) and Hegde et al. (2013).

inflammatory reaction with periodic acute flare-ups. The

Among all the four indirect tests, SCC showed highest

affected tissue eventually is destroyed resulting in reduced

efficacy of 74.55 % with respect to diagnosis of SCM. The

milk production (Sharma et al ., 2012).

efficacy of SCC is followed by CMT, WST and SFMT

The E. coli isolates in the present study accounted for 6.1%

which in accordance to Sharma et al . (2008). Hence all the

share and third most prevalent organism among different

animals found positive in SCC were selected for further

isolates of mastitis milk, which is very low with respect to

analysis under bacteriological prevalence and antibiotic

previous literature (Ranjan et al ., 2011). Despite E. coli is

sensitivity test. The data summarized in Table 2 indicates

the environmental pathogen, but low or sporadic incidence

the relative occurrence of various bacteria isolated from

of E.coli hasalsobeenreportedbyvariousworkers(Shukla

cows. The pathogens isolated from 82 milk samples,

et al ., 1998) as observerd in this study. Opsonization of

found positive under SCC, were Staphylococcus spp.

bacteria by IgM with subsequent phagocytosis and killing

38 (46.3%), followed by Streptococcus spp. 8 (9.76%),

by neutrophil are some of the factors, which prevent

Escherichia coli 5 (6.1%), mixed growth 27 (32.96%) and

Journal of Animal Research: v.5 n.1. April 2015

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