7Krebs S, Danuser J, Regula G. Using a herd health monitoring system in the assessment of welfare [J]. Acta Agric Scand: Animal Science, 2001, 50( 1 ): 78-81.
8Valle P S, Lien G, Flaten O, et al. Herd health and health management in organic versus conventional dairy herds in Norway[J]. Livestock Science, 2007, 112: 1-2.
9Salman M D, King M E, Wittum T E, et al. The national animal health monitoring system in Colorado beef herds: Disease rates and their associated costs[J]. Preventive Veterinary Medicine, 1990, 8 (2-3): 203-214.
10Losinger W C, Bush E J, Hill G W, et al. Design and implementation of the United States National Animal Health Monitoring System 1995 National Swine Study[J]. Preventive Veterinary Medicine, 1998, 34(2-3): 147-159.