Developing Management Options for Staph aureus on Organic Dairies

Project Overview

Project Type: Farmer
Funds awarded in 2020: $13,149.00
Projected End Date: 05/31/2021
Grant Recipient: Reed Farm
Region: Northeast
State: Maine
Project Leader:


  • Animals: bovine
  • Animal Products: dairy


  • Animal Production: animal protection and health, preventive practices, therapeutics
  • Education and Training: on-farm/ranch research
  • Production Systems: organic agriculture

    Proposal summary:

    Staph aureus is a common contagious mastitis organism worldwide, causing significant economic losses on both organic and conventional dairy farms. Decades of research have developed extensive knowledge about this antibiotic resistant organism, but successful treatment and prevention through vaccination remains low, and the challenge remains for farmers. Management of the problem relies heavily on culling infected cows and on cultural practices to prevent new infections of healthy cows. In the summer of 2018, we experienced an outbreak of Staph aureus on our organic dairy. About one third of our herd tested positive, including several young cows, making it cost prohibitive to cull of all the infected cows. This proposal seeks to test recommendations from New Zealand that may help prevent new infections, and that show potential to help cows overcome existing cases. For this study, we will adopt rigorous milking hygiene and cattle management practices as part of our day to day operations, and trial new dry cow treatments and management approaches. We will culture milk samples of Staph aureus positive and negative cows on a frequent testing schedule to evaluate the efficacy of the dry cow treatments and aim for 100% prevention of new cases in mid-lactation cattle during the study period. We will share our findings electronically through frequently used online dairy forums, a presentation at Wolfes Neck Center’s Organic Dairy Farmer Training Program in Freeport, ME, and a presentation at a milk quality workshop in cooperation with the Maine Organic Milk Producers and UMaine Cooperative Extension.

    Project objectives from proposal:

    In a second year of study testing staph aureus management in the practical setting of a working organic dairy, our research would seek to:

    1) Test the effectiveness of milking hygiene and preventative management protocols from the US and New Zealand. We will monitor staph aureus negative cows to determine if the adoption of the recommended practices results in zero new infections—100% prevention—during the one year study period.

    2) Trial Manuka honey therapy as (a) a dry cow treatment, and (b) a mid-lactation mastitis treatment; this would be approved under the National Organic Standards to replace antibiotic treatments typically used in conventional production. The mid-lactation treatment a new study question for the 2020 study.

    3) Trial long dry periods (105+ days) as suggested by experts in New Zealand, that may allow a staph aureus infected cow to “self cure”.

    4) Trial dry-off strategies. Cold-turkey dry-off and New Zealand once-a-day dry-off will be compared for staph aureus negative cows to see if one strategy is preferable for preventing new mastitis infections.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.