We invite applications for the PhD position on “Optimization of culling decisions with respect to dairy cow health management”. This position will be part of a collaboration between the Faculty of Veterinary Medicine – Utrecht University (Department of Farm Animal Health) and Wageningen University (Business Economics Group). 

One of the most urgent environmental issues is global warming, induced by greenhouse gas (GHG) emissions. In Western Europe, the annual emissions of the livestock sector is over 0.6 gigatonnes of CO2-equivalents. About one thirds of these emissions is ascribed to milk production. Besides GHG emissions, dairy production faces mineral soil surplus problems. In addition, animal welfare is an urgent issue, and there is a lot of attention to improve welfare. Dairy farming in the Netherlands has thus to deal with changing production circumstances, changing laws and rules on GHG emissions, phosphate production and animal welfare.

On average 25-30% of the Dutch dairy cows are replaced annually. The major reasons for culling cows are low production and health problems. Decisions to replace dairy cows are primarily based on considerations focussing on economic sustainability rather than overall sustainability. Currently, the average age of cows is 6-7 years. From an environmental as well as welfare perspective this longevity is considered too short, or in other words cows are culled too early. Various studies on culling management have been performed in the Netherlands. These studies mainly focussed on the impact of culling on economic herd performance under milk quota circumstances and consequently are no longer representative under current production constraints and sustainability and animal welfare objectives.

One of the reasons to cull cows, and thus not reaching a higher culling age, is the occurrence of endemic production diseases (e.g., mastitis, lameness, infertility, ketosis). Probably, the interaction between these diseases has an influence on the culling as well. Previous research on culling decisions included a single disease status of the cow, but did not account for any interaction between diseases.

There is thus a need for new decision support models on culling which can take into account the changing laws and rules on GHG emissions, phosphate production and animal welfare. Such a model can be an optimization model that takes into account several constraints (e.g., limited amount of GHG emission and phosphate production) and goal functions (e.g., age of the cows of at least … years). Moreover, including the interaction between diseases and the interaction of that with culling can improve such optimization models.

Within the PhD project, the following objectives will be addressed: i) investigating coherence between production diseases in occurrence and their influence on herd health management (based on an observational study and literature study; ii) investigating culling decisions and risk factors on culling for Dutch dairy farms based on available data; iii) developing an optimization model on culling accounting for different constraints and goal functions (such as welfare improvement).

We are looking for a motivated, enthusiastic and analytically strong candidate with a broad interest (economics, epidemiology, mathematical modelling, animal science/biology). The candidate should have mathematical modelling experience, good communication and writing skills, and enjoy to work in a multidisciplinary team. Proficiency in English (both oral and written) are a prerequisite. The applicant must hold at least a relevant Master’s degree Science (e.g., Veterinary Medicine, Animal Science, Biology). Knowledge on Dutch dairy farming is desirable.

We offer a temporary position (1.0 FTE) for one year, with an extension to four years. The gross salary - depending on previous qualifications and experience  - ranges between €2,266 and €2,897 (scale P according to the Collective Labour Agreement Dutch Universities) gross per month for a full-time employment. Salaries are supplemented with a holiday bonus of 8 % and a year-end bonus of 8.3 % per year. We offer a pension scheme, (partly paid) parental leave, collective insurance schemes and flexible employment conditions (multiple choice model). More information is available at: working at Utrecht University.

A better future for everyone. That ambition motivates our academics to do their top-level research and provide inspiring education. At Utrecht University, colleagues from various disciplines collaborate intensively on socially-important themes. Our focus is on Dynamics of Youth, Institutions for Open Societies, Life Sciences and Sustainability.

The Faculty of Veterinary Medicine has a unique position in the Netherlands. Not only is this the only institution where veterinarians are trained, researchers are also working together on innovative scientific research. In addition, the Faculty provides specialist clinical care in the largest academic veterinary hospital in Europe. Thanks to this position, the Faculty of Veterinary Medicine is a point of contact for all veterinary matters, both nationally and increasingly internationally. The Faculty employs approximately 900 veterinarians, scientists and support staff and counts 1,500 students.

The PhD project will take place in cooperation with the Business Economics (BEC) group of the Wageningen University. BEC holds a strong position in interdisciplinary research with key areas, such as food supply chain economics, bioeconomic modelling, and economics of animal health, food safety and plant health. Also, BEC is active in measuring and modelling performance and risk management of agro-supply chains and farms.