Electrical conductivity in fraction-collected quarter milk samples with low somatic cell counts

Electrical conductivity and somatic cells were measured in fraction-collect ed quarter milk samples of 32 quarters (8 cows) at 3 morning and 3 evening milkings to compare the diagnostic capacity. The mean somatic cell count in the foremilk fraction (FOM) was 44,000 cells/ml. The intermilking interval s were 10 and 14 h. The first milk jets (FIM), the milking fractions of the last minute of milking (L-3, L-2, L-1) and the stripping fraction (SM) sho wed significantly increased cell count levels compared to the fractions of the first minute of milking (F-1, F-2, F-3). The highest cell count value w as measured in the SM fraction (195,000 cells/ml). The electrical conductiv ity showed a plateau in the fraction FOM to L-3 and the values in the fract ion L-2 to SM were significantly decreased compared to the values of the ea rlier fractions. The lowest conductivity values were found in SM. To evalua te the influence of the intermilking interval and the udder health status t he quarters were split into 2 groups based on the threshold value of 50,000 cells/ml in the FOM fraction. Group 1 (G1) had a mean value of 18,000 cell s/ml, group 2 (G2) a mean of 95,000 cells/ml. The first 4 milk fractions (F IM to L-3) had at evening milking after an interval of 10 h significantly i ncreased cell counts but significantly decreased electrical conductivity va lues compared to the corresponding values at morning milking. The somatic c ell count indicated a higher diagnostic capacity compared to the electrical conductivity due to significant differences between G1 and G2 in all milk fractions which were not identified for the electrical conductivity.