National cross-sectional study of mastitis in dairy cattle in Jordan.

Between July 1991 and August 1992, 63 Jordanian dairy farms selected by stratified random sample were visited to identify the major causes and prevalence of intramammary infections in dairy cows. Of 773 cows examined 60% of all sampled quarters had > 283,000 cells/ml. The mean value of somatic cell count (SCC) was positively associated with age in lactations and negatively with herd size. Cows milked by bucket milking machines or in fully automatic parlours had a lower mean SCC than those milked by hand. Many management faults pertaining to milking procedure and maintenance of milking machines were noted. The most common isolate from clinical cases was Staphylococcus aureus (37.5%). Estimates of prevalence of bacterial pathogens in intramammary infections were: coagulase negative staphylococci (16.04%), S. aureus (9.41%), Klebsiella spp. (6.17%), Corynebacterium bovis (5.35%) and Brucella melitensis (4.52%). The results demonstrate the essential need for the development of a national mastitis control programme.