Evaluation of automatic mastitis detection equipment.

An electronic sensor was evaluated as an instrument for early detection of mastitis. This method involved measuring the conductivity of milk continuously throughout the milking process and then establishing a conductivity ratio. The lowest conductivity measurement of the four quarters was a basis for assessing the degree of mastitis in the other quarters. This assumed that at least one of the quarters was normal at examination and the lowest reading was normal conductivity. The conductivity ratio was evaluated by comparison with the leukocyte concentration and combined leukocyte concentrations and cultural examiniations of milk samples from 1028 quarters. In healthy cows conductivities of milk from each of the quarters were similar. If, however, one or more quarters were infected, this milk showed higher conductivity compared to the noninfected quarter of the same cow. The conductivity ratio correctly identified 69% of the established cases of mastitis. For the Wisconsin Mastitis Test, 93.2% of the normal quarters were detected correctly by the conductivity ratio. Leukocyte counts were frequently high when there was no other evidence of mastitis. We believe the conductivity ratio is effective in detecting mastitis at an early stage of infection caused by most of the pathogenic microorganisms.