Abstract:
The control of the infections intramammaires represents a paramount stake for the
dairy stockbreeders. To fight against this pathology passes by a knowledge of the
bacteria in causes and their epidemiology.
The present study related on the one hand, on the evaluation of the prévalence of
the germs responsible for the clinical mastitis and the study of some aspects of their
epidemiology in 35 dairy herds and on the other hand, to evaluate the prévalence
and the etiology of the subclinic mastitis in the cows at the end of the lactation in
four dairy herds. The performance of the CMT to identify subclincal mastitis at the
end of the lactation was evaluated. The in vitro antimicrobial susceptibility of bacteria
isolated from cow milk samples was tested. Treatment of dairy cows at drying off
has been practiced.
Results obtained showed :
A strong prévalence (32,6%) of the clinical cows with clinical mastitis. The
bacteriological analysis of 252 milk samples milk showed : 28,4% of Staphylococcus
aureus, 21,6% of Eschérichia coli, 13,7% of Streptococcus agalactiae. The
coagulase negative staphylococci with a frequency of 10,8% seem increasingly
accused in the clinical mastitis.
The prévalence of the cows with subclnical mastitis at the end of the lactation is
73,6% and the quarters 40,3%. The frequency of the germs responsible for subclnical
mastitis was estimated on 121 cows at the end of the lactation. Out of he 464 milk
samples, 59,7% were bacteriological negative. The germs observed most often are :
Staphylococcus aureus (30,9%), coagulase negative staphylococci (25,9%),
Streptococcus agalactiae (23,2%) and Eschérichia coli (15,9%).
Staphylococcus aureus is the predominant bacterial pathogen in subclinical and
clinical mastitis. Environmental pathogens are not to neglect in the cause of the
clinical mastits.
Moreover, this study revealed the presence of antibiotic residues in 17,1% of the 35
milk samples analyzed.
The in vitro antimicrobial susceptibility of bacteria isolated from cow milk samples
showed high resistance to penicillin, ampicillin, oxacillin, tetracyclin, streptomycin
and erythromycin.
During the dry period, the treatment eliminates 91% of pathogenic organism. The
rate of new infections prevented is 88%.
