The prevalence of some mastitis pathogens in bulk milk of Dutch dairy goats and the relationship with bulk milk somatic cell count and bulk milk standard plate count.
Summary
The aim of this study was to assess the correlation of bulk milk somatic cell count (BMSCC) with bulk milk standard plate count (BMSPC) and with the number of coliform bacteria, coagulase negative staphylococci (CNS) and S. aureus. We also described the prevalence of these pathogens in bulk milk of Dutch dairy goat farms. In total 53 dairy goat farms participated in this study. Bulk milk was collected 3 times with an interval of two weeks during the months January, February and March and was examined on BMSCC, BMSPC, bulk milk coliform count (BMC), bulk milk coagulase negative staphylococci count (BMCNS), bulk milk manitol fermenting staphylococci count (BMMFS) and on the presence of S. aureus. No correlation was found between BMSCC and BMSPC. Significant factors affecting BMSCC were BMCNS (correlation coefficient 0.16) and BMMFS (correlation coefficient 0.08). The amount of S. aureus positive milk samples (0,1,2 or 3 out of 3) did not affect the mean BMSCC. BMSPC was determined for 20% by BMMFS and for 13% by BMCNS. Coliforms do not seem to affect BMSCC and BMSPC. S. aureus was present in 53.5% of 159 milk samples. On 85% of all the participating dairy goat farms S. aureus was found in 1 or more milk samples. On 20.8% of the participating farms S. aureus was found in all milk samples. All milk samples contained CNS and 86.8 % of the samples contained coliforms. This study shows that mastitis pathogens are responsible for some of the variation in BMSCC and BMSPC, suggesting that udder health programs can positively influence the BMSCC and BMSPC. Therefore both BMSCC and BMSPC can be useful tools in evaluating udder health status of dairy goat herds.