Occurrence of mastitis pathogens in relation to somatic cells

Abstract

There were examined 161 cows from 4 farms in total. The suspect animals were selected according to viscosity test results, clinical symptoms and somatic cell count (SCC). Milk samples were examined for the presence of pathogens and for SCC. 55 mastitis pathogens were identified. The most frequently isolated species was Enterococcus faecalis (n = 20), followed by Staphylococcus aureus (n = 6) and Streptococcus uberis (n = 5). The SCC ranged from 9 to 24 204 ths.ml−1. There was positive occurrence of bacteria genus Staphylococcus and Enterococcus at lower SCC (50 ths.ml−1) and at higher SCC numbers (> 300 ths. ml−1) bacteria genus Streptococcus, Enterobacter and Escherichia coli. Differences in SCC were significant (P < 0.001) in negative samples xg 131 SCC versus 491 for positive, 611 for staphylococci and 464 ths.ml−1 for other positive. SCC discrimination limit for practical likelihood of pathogen occurrence estimation in infectious sample groups was calculated. This limit for suspicion of infection is 159 for positive group, 113 for staphylococci and 174 ths.ml−1 for other positive. This could be possible to recommend the value 174 ths.ml−1 for practical use with target to apply preventive or curative measures.

Keywords

• cow’s milk
• <i>Staphylococcus aureus</i>
• <i>Staphylococcus haemolyticus</i>
• <i>Streptococcus uberis</i>
• discrimination limit