Defense of Baptiste Sorin's thesis

Members of the jury:

• Reviewers before defense:
  • Egil FISCHER, Associate Professor, Universiteit Utrecht, United Kingdom
  • Amandine VEBER, Research director, CNRS,
• President:
• Examiners:
  • Timothée VERGNE, Associate professor, ENVT/INRAE, Toulouse, France
  • Beatriz GARCIA MORANTE, Research associate, IRTA/CreSA, France
  • Catherine BELLOC, Professor, Oniris/INRAE, Nantes, France
• PhD director:
  • Pauline EZANNO, Research director, Oniris/INRAE, Nantes, France
• PhD Co-supervisor:
  • Sébastien ASSIE, Associate professor, Oniris/INRAE, Nantes, France

Abstract:

Bovine respiratory diseases (BRD) are complex illnesses involving various factors. They are a major concern in the cattle industry, both economically and in terms of animal health. This thesis proposed using modeling approaches to simulate intervention strategies in a herd affected by BRD. First, we studied the impact of grouping young cattle on the circulation of three pathogens associated with BRD in a feedlot farm with several groups. The results showed that fattening high-risk animals together rather than separately helped reduce the incidence of BRD.Next, we modeled collective treatment strategies and the criteria for triggering them in feedlot farms.
We also tested automated early warning methods as a criterion for triggering collective treatments. The simulation results showed the potential of these alerts to reduce the incidence of BRD and the use of antibiotics. Finally, we explored coinfection models and studied the impact of vaccination in a farm where both a virus and a bacterium are circulating. This work allowed us to convert epidemiological outcomes into economic data and to identify a cost-effective vaccination
coverage for industry stakeholders.

Keywords :

Stochastic Modeling; Decision support tool; Coinfection; Animal Health; Feedlot cattle