[1] Suisselab AG Zollikofen, CH-3052 Zollikofen, Switzerland
[2] Univ Bern, Vetsuisse Fak, Vet Publ Hlth Inst, CH-3097 Liebefeld, Switzerland
[3] Agroscope Liebefeld Posieux ALP, Labor Mol Mastitisforschung, CH-3003 Bern, Switzerland
[4] Univ Bern, Vetsuisse Fak, Zentrum Zoonosen Bakterielle Tierkrankheiten & An, Inst Vet Bakteriol, CH-3012 Bern, Switzerland
[5] Univ Bern, Vetsuisse Fak, Wiederkauerklin, CH-3012 Bern, Switzerland