Funding for this research was provided by:
Merck Animal Health
Received: 13 January 2020
Accepted: 7 December 2020
First Online: 4 January 2021
Ethics approval and consent to participate
: Blood sampling was done in the course of routine diagnostics on farm; therefore animal ethics committee approval was not required. Prior to begin of the study owner consent was obtained from all participating farmers.
: All authors agreed to the publication of the present manuscript.
: All authors confirm the absence of competing interests. HS conducted the laboratory analyses under blinded conditions and KF supported in the identification of herds matching inclusion criteria, in the communication of study aims and results as well as in the interpretation of economic farm data.