Contribution à l'étude des infections intramammaires de la vache laitiere dans l'Est algeriens
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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%.