Movement of infection between milk tubes, teat cups, and teats with a jacketed airflow cushion in a single chamber teat cup.

Transfer of bacteria between teat cups, between teats of the same cow, and between teats of different cows was investigated by tracer bacteria applied to teat skin and by injection of tracer bacteria or colored fluids into the short milk tube. In spite of the unidirectional flow of milk and air with the single chamber teat cup, no advantage over a conventional system in transfer of tracer bacteria from cup to cup, teat to teat, and cow to cow showed.