outline of potential critical control points for biosecurity and biocontainment on large dairy farms Aurora

JAVMA, Vol 230, No. 6, March 15, 2007 T US dairy industry is moving toward fewer dairy farms with more cattle per farm. Between 1995 and 2005, the number of dairy farms decreased by 43.9% (from 139,670 to 78,295), but the total number of milk cows decreased by only 4.5% (from 9.47 to 9.04 million). Consequently, the average herd size for dairies in the United States has almost doubled during the past 10 years. It has become difficult for dairy farms to be completely self-sufficient, self-contained production units. Large dairy farms are at risk of exposure to disease agents from external sources of labor, feedstuffs, replacement cattle, supplies, and vehicles. In a USDA study, it was estimated that 75.3% of large US dairy farms brought new cattle into the herd in 2001. Large dairy farms typically focus on milk-producing cows and may contract with outside services to manage their calves, heifers, or nonlactating cows. Numerous vehicles travel among several dairy farms on a daily basis; some of these collect milk, calves, or carcasses, whereas others deliver feedstuffs, pharmaceuticals, or genetic materials. Wildlife, rodents, and birds have access to dairy farms and pose a risk for transmission of disease. It is estimated that wild ruminants have physical contact with dairy cows or feedstuffs on 53% of US dairy operations. Interaction with all the aforementioned outside resources can increase the likelihood of introducing disease agents to a farm. This risk can be minimized by establishing and adhering to a structured biosecurity plan. Biosecurity is the result of management practices designed to avoid introduction of disease agents to a farm. Disease agents may include toxins or infectious pathogens, such as bacSuggested outline of potential critical control points for biosecurity and biocontainment on large dairy farms