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The Transitioning Dairy: Identifying and Addressing Challenges and Opportunites in Milk Quality and Safety

Tikofsky, Linda
Cornell University
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The goal of this project is to gain insight into changes in udder health, milk quality and milk safety that may arise during the transition of dairy cow herds from conventional farming to organic farming, and to propose and disseminate methods to maintain or promote udder health and milk quality in organic dairy farming.
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Conventional farming relies heavily on use of antimicrobials to maintain udder health and milk quality. Withdrawal of antimicrobials constitutes a major change in mastitis control options during the transition to organic farming. This project aims to identify challenges in mastitis control and maintenance of milk quality and safety as a result of withdrawal of antimicrobial treatment and other changes in management associated with the transition to organic farming. In addition, this project aims to determine whether changes in management, housing and nutrition may benefit milk quality and safety, for example in terms of presence of neutraceutical components or absence of bacteria with antimicrobial resistance genes. The objectives will be pursued through analysis of milk samples and interaction with participating farmers. Specifically, five herds will be monitored longitudinally during their pre-transition, transition and post-transition years. Data will be collected on udder health (incidence of clinical mastitis, prevalence of subclinical mastitis, mastitis pathogens), bulk tank milk quality (bacteriology, somatic cell count, selenium level, conjugated linoleic acid content) and food safety (food-borne pathogens, antimicrobial resistance). Subsequently, intervention strategies will be proposed so that future transitioning dairy producers can be proactive in addressing the challenges. The findings of this study and the strategies derived from it will be developed in collaboration with and disseminated to the organic community through participatory evaluation, farmer discussion groups, traditional extension approaches, newsletters, the internet and pasture walks on certified and transitioning dairy farms. The organic dairy (OD) sector is growing rapidly, due to increased consumer interest in animal welfare, environmental stewardship and potential health benefits of OD. To meet the demand for organic milk and dairy products, farmers who farmed conventionally are transitioning to organic production. In conventional farming (CF), antibiotics are often used to maintain cow health and milk quality, specifically to control bacterial infections of cows' udders. Without antibiotics, maintenance of infection-free udders is a major challenge. As a result, cow health, milk quality, and milk safety may be at risk. Organic management may have benefits. Cows may develop healthier immune systems and milk may contain increased levels of selenium and conjugated linoleic acid (CLA) as a result of grazing. Withdrawal of antibiotics may result in a lower risk of antimicrobial resistance in milk. Researchers and farmers will work together during the transition of 5 farms from (CF) to organic farming. During the transition, (pre-transition, transition, and post-transition years), cow health and milk quality will be monitored closely, with emphasis on udder infections, bacteria and antimicrobial resistance, and levels of selenium and CLA in milk. They will identify challenges and opportunities in udder health and milk quality associated with the transition to organic farming, and will develop management strategies to produce high quality milk from healthy cows under organic farming conditions. They will share their experience and advice through workshops, pasture walks, newsletters and websites. Through collaboration with NOFA-NY (Northeast Organic Farming Association of New York, Inc.) and NODPA (Northeast Organic Dairy Producers Alliance) we will enroll five dairy herds in the North-Eastern USA that are in the process of transitioning from conventional farming to organic farming. Transition of soils and crops will be in progress, while conventional methods, including antimicrobials, will still be in use for mastitis control. Herds will be identified and enrolled during the first six months of the project. Each herd will be monitored for three subsequent years: 1. the last year before withdrawal of antimicrobials and other non-organic inputs for dairy animals (pre-transition year); 2. the first year of withdrawal of non-organic inputs (the transition year); and 3. the first year of certified organic farming (post-transition year). During each of those years, bulk tank milk samples will be collected monthly and whole herd surveys (quarter milk samples) will be performed quarterly. In addition, animal health data and quarter milk samples from cows with clinical mastitis, at calving, and at dry-off will be collected by herdsmen. Bulk tank samples will be analyzed for conjugated linoleic acid, selenium, somatic cell count, fat, protein, and bacteria, including food-borne pathogens and bacteria with antimicrobial resistance. Quarter milk samples will be used for mastitis bacteriology, detection of antimicrobial resistance and SCC measurements. Detailed longitudinal observations will allow us a) to identify challenges and opportunities in terms of maintenance of udder health and milk quality and safety; b) to identify specific testable hypotheses for future investigation, and c) to propose intervention strategies to prevent or address udder health and milk quality issues. Participating farms will be involved in quarterly farm evaluations and self-assessments and in general and customized training sessions on milk quality, food safety, and cow health. A combination of quantitative and qualitative information will be collected to help farms make improved management decisions and to develop a manual to help guide other farms and their consultants to improve organic dairy management. Towards the last two years of the four-year project, an increasing amount of time will be devoted to education and outreach. Participatory evaluation meetings will be held, in which stakeholders from all participating farms and the project team will be provided with an opportunity to communicate and interact and to develop an experience and reality-based management program that can be used to support newly transitioning herds in the future. The results of the project and the materials developed from it will be disseminated to other existing and transitioning organic producers in a variety of ways, including 2-day workshops for farmers, pasture walks, newsletters and websites from organic organizations (e.g. NODPA, NOFA-NY), and a Dairy Transition Manual, so that producers, veterinarians, extension educators and industry personnel throughout the country will have access to the information and insight gained from this project.
Funding Source
Nat'l. Inst. of Food and Agriculture
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Bacterial Pathogens