Farms and animals

Thirteen dairy herds in the North-West of France were visited twice during spring 2012. The first visit took place around the date of turn out, and the second 1.5 to 2 months after turn out. Eleven of these herds were already included in a previous randomized controlled clinical field trial conducted in autumn 2011 [25]. The major herd recruitment criteria were the breed (Holstein), an access to pasture (with at least 1/3 of grazed grass in the cows’ diet), no intention of anthelmintic treatment on adult dairy cows in the upcoming grazing season, and a daily recording of MP (automatic milking system, or milk parlor with milk meters). In each herd, the majority of lactating cows were included provided that they were planned to be milked for at least 5 weeks after the second visit and in apparent good health.

This study was carried out in commercial dairy farms, so on "private lands". On the basis of an accurate description of the objectives of the study and its design, the owners of the lands (the farmers) gave permission to conduct the study on their farm, accepted to follow the protocol and to participate in the handling of cows. Except this informed consent of each farmer and his permission to conduct the study on his farm and on his animals, no other specific permission was required.

This field study did not involve endangered or protected species. No cows were sacrificed for the purposes of the study.