Abstract
The aim of this paper was to evaluate the effects associated with intramammary infection (IMI) by a bacterium or a group of bacteria (Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, coliforms, Staphylococci other than S. aureus, and Corynebacterium bovis) on the somatic cell count (SCC) in quarter milk of dairy cows. Papers selected for analysis had to provide SCC values associated with the natural infection in quarters by different bacteria. Sampling for measurement of SCC and determination of the infection had to be done on the same day. Only papers published in English or in French after 1971 were considered. Twenty-one papers fulfilled the selection criteria. The animals sampled, the measurement techniques for SCC and the bacteriological identification, as well as the definition of the infection, all differed widely among the selected studies. The meta-analysis method was used to estimate both the mean SCC (arithmetic and geometric) value and the average increase on SCC of each type of infection. The geometric mean SCC in bacteriologically negative quarters was 68 000 c/mL. In case of IMI, the retained SCC was 357 000, 857 000, 547 000, 1 024 000, 1 151 000, 138 000 and 105 000 c/mL in quarters infected by Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, coliforms, staphylococci other than S. aureus and Corynebacterium bovis, respectively. The variation factors that could influence these SCC values and the bacteriological results are discussed.
Highlights
Mastitis is an inflammation of one or several mammary quarters, most often due to a bacterium-related infection
The aim of this paper was, after a presentation of the range of reported values of somatic cell counts (SCC) for the main bacteria involved in intramammary infection (IMI), to carry out a meta-analysis with the aim to estimate an average effect associated with an IMI by a given bacterium on the SCC
The aim of this paper was to assess a summary effect associated with an IMI by a given bacterium on SCC by meta-analysis on the selected papers
Summary
Mastitis is an inflammation of one or several mammary quarters, most often due to a bacterium-related infection In some cases, this inflammation is accompanied by clinical signs (pronounced signs of mammary inflammation and systemic illness). This inflammation is accompanied by clinical signs (pronounced signs of mammary inflammation and systemic illness) The minor pathogens, on the contrary, are most often associated with a moderate infection rarely associated with clinical signs. These infections, which are especially frequent, are mainly due to Staphylococci other than S. aureus (mostly S. chromogenes, S. hyicus, S. epidermidis, and S. xylosus) or to Corynebacterium bovis [38]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
