A longitudinal study of mastitis on an experimental farm with two herds, one managed organically, the other conventionally.

Mastitis in two herds managed as a comparison between organic and conventional dairy farming systems was monitored for 4 years utilising regular bacterial culture of milk samples, individual and bulk somatic cell counts and observation by farm staff. The objective was to develop strategies for the control of mastitis in organic cows without the use of antibiotics. The herds showed differences in clinical mastitis incidence, subclinical mastitis prevalence and bulk milk somatic cell count. Despite these differences, the level of mastitis in the organic herd remained manageable.