Incidence risk and aetiology of mammary abnormalities in dry ewes in 10 flocks in Southern Greece

In a field investigation of 10 flocks in Southern Greece, 3367 dairy ewes w ere examined twice, in order to estimate the incidence risk and the aetiolo gy of mammary abnormalities during the dry-period. Abnormal secretion, lump s, nodules, diffuse hardness, abscesses and cysts were the abnormalities de tected. The cumulative incidence of mammary abnormalities during the dry-pe riod was 5.1% (95% confidence interval: 4.4-5.8%); 47% of the cases detecte d developed during the first three weeks after cessation of lactation. Desp ite variation in the nock size, there was no between-flock variation in the risk of a ewe developing mammary abnormalities. Staphylococci (Staphylococ cus aureus and coagulase-negative isolates) were the most frequently isolat ed bacteria from mammary samples; Actinomyces pyogenes, Clostridium perfrin gens, streptococci and Escherichia coli were also isolated. Resistance was encountered among the staphylococcal isolates. (C) 1998 Elsevier Science B. V. All rights reserved.