Received: 1 February 2018
Accepted: 17 December 2018
First Online: 27 December 2018
Ethics approval and consent to participate
: The inclusion of the dogs in the study was approved by the veterinary office of the canton of Zurich and was in accordance with the guidelines and directives established by the Animal Welfare Act of Switzerland (TVB 191/13). Written consent of all pet owners was obtained before including the dogs in the study.
: Not applicable.
: The authors declare that they have no competing interests.
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