Etiological factors of mastitis in Polish Merino ewes

Abstrakt

Etiological factors of mastitis in Polish Merino ewes were determined. The study was carried out in 2004 and 2005 in sheep farms of the NRIAP Experimental Stations in Kołuda
Wielka and Pawłowice in a group of 71 and 74 ewes with an elevated somatic cell count in milk (SCC > 500,000 per cm3). During lactation, they were sampled three times for milk and a total of 610 samples were obtained. All the samples were subjected to microbiological analyses to determine pathogenic microorganisms in milk. The plate method and API tests were used for the determinations. As the somatic cell count in milk increased, the proportion of infected samples was observed to increase, and this tendency occurred on all three dates of milk collection. The following pathogenic microorganisms were detected in the milk: Streptococcus uberis, Streptococcus agalactiae, Enterococcus sp., Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus sp., Arcanobacterium pyogenes, Escherichia coli, Pseudomonas aeruginosa, and Candida sp. In the first year of the study, the most often isolated bacteria were streptococci, and Streptococcus uberis was detected in the greatest number of milk samples (30%). In the second year, staphylococci dominated in the
infected milk, with Staphylococcus aureus being the most common pathogen (in ~25% of the samples). Pathogens identified in the present study represent the microflora typical of milk, produced by mastitic udders; therefore, they can be considered as etiological factors of the subclinical and clinical forms of mastitis in Polish Merino ewes.