1. Dipartimento Di Medicina Veterinaria, Università Degli Studi Di Milano, Lodi, Italy
2. Porto Conte Ricerche, Tramariglio, Alghero, Italy
3. Institute of Agricultural Biology and Biotechnology, National Research Council, Lodi, Italy
4. Quality Milk Production Services, Animal Health Diagnostic Center, Cornell University, Ithaca, NY, USA
5. Istituto Zooprofilattico Sperimentale Della Sardegna “G. Pegreffi”, Sassari, Italy