Funding for this research was provided by:
Received: 8 September 2018
Accepted: 28 February 2019
First Online: 6 March 2019
Ethics approval and consent to participate
: All samples in the Dutch and Chinese datasets were collected in accordance with the guidelines and protocols for the care and use of animals approved by the ethical committee on animal experiments of Wageningen University (protocol: 200523.b) and the Animal Welfare Committee of China Agricultural University (Permit Number: DK996), respectively. All procedures to collect the Danish samples followed the protocols approved by the National Guidelines for Animal Experimentation and the Danish Animal Experimental Ethics Committee, and that all sampling was restricted to routine on-farm procedures that did not cause any inconvenience or stress to the animals, and hence, no specific permission was required.
: Not applicable.
: The authors declare that they have no competing interests.
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