Economic decisions in mastitis management

This thesis was conducted with the main objectives (i) to calculate costs of mastitis and cost-efficiency of mastitis management measures and (ii) to acquire insights in the economic decision behaviour of dairy farmers with respect to mastitis management. Animal health economics is a decision supporting science, based on a decision making function of evaluating and choosing between alternative strategies on animal diseases. The potential economic importance of diseases such as mastitis is not uniform across farms, regions or countries, and control measures justified in one context may not be economically worthwhile in another. The average costs of mastitis were calculated as €77 per year per cow present on the farm under quota situation. Most of the farmers (72%) underestimated the costs of mastitis on their farm. The main reason for this underestimation was that farmers underestimated production losses caused by cows with an elevated somatic cell count. The costs of mastitis as calculated by the farmers varied between €17 and €200 per cow per year on farm level. It was found that farms that have a comparable incidence of clinical mastitis and bulk tank somatic cell count may have different costs of mastitis. Because decisions are often based on the perception of a problem, farm specific cost calculations can help to give a better insight in the magnitude of the decision. This can improve the adoption rate of advised management measures. Decisions are not only based on economic parameters or other quantified characteristics. Mastitis management is known as one of the fields where farmer decision making often deviates from recommendations based on rational standard-economic models and is often contrary to advices given by veterinarians and other advisors. Farmers can have different motivations to decide on the implementation of management measures to improve the udder health situation on the farm. It is necessary to understand the important motivators of dairy farmers to be able to successfully transfer knowledge and technology to the dairy farm. The tools developed in this thesis can provide support in economic decisions, which can improve the motivation of a farmer to improve mastitis management. In general, farmers prefer to invest in short or long term investments, rather than to invest in extra labour or in changing routines. The large variation in preferences between farmers showed the importance of including this information in farm specific decision support. Not every farmer can earn money by improving the udder health situation by adopting new management measures, but many can. Clear differences between the costs and benefits of management measures exist for different farm situations. The results of this thesis have contributed to our understanding of the decision making process of dairy farmers regarding mastitis management