Received: 17 February 2021
Accepted: 29 April 2021
First Online: 20 May 2021
: This study was conducted according to the Swiss law for Animal Welfare and approved by the the cantonal veterinary office of Solothurn (Licence Nr. SO 18/01 29818). In addition an informed consent was signed by the farmer.
: Not applicable.
: There are no competing interests of any of the authors that could inappropriately influence or bias the content of the paper.