Brouwers, Ad http://orcid.org/0000-0002-7514-8400
Dingjan, Pieter G.
Dujardin, Ben
van Zoelen, Everardus J.
Lips, Paul
Gooren, Louis J.
Article History
Received: 16 November 2017
Revised: 9 February 2018
Accepted: 15 February 2018
First Online: 26 February 2018
Compliance with ethical standards
: The study was performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments at the time of data collection. All persons gave their informed consent prior to their inclusion in the study. Details that might disclose the identity of the subjects under study have been omitted.
: PL has received honorarium from Friesland Campina dairy industry for advice. The other authors have no potential conflict of interests to declare.