Reducing use of antimicrobials — Experiences from an intervention study in organic dairy herds in Denmark

Abstract

With the aim of phasing out the use of antimicrobials 23 Danish organic dairy producers from the same organic dairy company participated in Stable School farmer groups from February 2004 to March 2005 in order to go through a common learning and development process towards their common goal. Data on production and herd health were evaluated from two years before to three years after the start of the Stable Schools. For comparison, data was collected from the remaining 35 herds delivering to the same dairy company, 118 organic dairy herds delivering to other dairies and 115 conventional herds. On average, the project herds were smaller with lower production and had half the incidence rate of mastitis treatment than the organic herds from other dairies before the start of the project. The incidence rate of mastitis treatments was reduced considerably from 20 treatments per 100 cow years to 10 treatments per 100 cow years after the project period. Somatic cell count (SCC) and scores for acute and chronic intramammary infections did not change significantly during the study period, and milk production increased at the same rate as in the other herd groups. The incidence rate of mastitis treatments or the reduction of the incidence rate could be related to the herd SCC or the prevalence of blind quarters. The incidence rates of locomotive disorders and reproductive disorders were lower in the project herds compared with herds from other dairies before the project start, and the differences increased during the project period though the reduction of the incidence rates in the project herds was not statistically significant. It is concluded that the farmers participating in the Stable Schools managed to reduce the use of antimicrobials in their herds also after the project period without apparent negative effects on production and udder and herd health.