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

Abstract

T he 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). 1 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, 2 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. 3,4 It is estimated that wild ruminants have physical contact with dairy cows or feedstuffs on 53% of US dairy operations. 2 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. 5 Disease agents may include toxins or infectious pathogens, such as bac-Suggested outline of potential critical control points for biosecurity and biocontainment on large dairy farms

A survey on biosecurity and management practices in selected Belgian cattle farms

“…The recommended isolation period length varies, but for diseases with a short incubation period preferably three to four weeks is advised (Wells et al, 2002;Barrington et al, 2002;Callan and Garry, 2002;Villarroel et al, 2007). Even when animals are tested upon arrival, they should be quarantined until test results are available, which very often was not done.…”

“…external biosecurity) and reducing the spread of pathogens within a herd (i.e. internal biosecurity or biocontainment) (Villarroel et al, 2007;Laanen et al, 2013). The implementation of biosecurity measures reduces disease spread and is therefore part of the measures frequently proposed in the control of several infectious diseases.…”

Herd factors associated with dairy cow mortality

“…Disease prevention is a multifaceted endeavor best addressed through the same principles as those of the Hazard Analysis and Critical Control Point system (Villarroel et al, 2007). Similarly, the prevention of the multitude of poor choices and harmful practices that can negatively influence mortality levels is best served by such an approach.…”

Management practices as risk factors for the presence of bulk milk antibodies to Salmonella, Neospora caninum and Leptospira interrogans serovar hardjo in Irish dairy herds

“…As bulk milk analysis is becoming an important diagnostic tool at farm level for the purposes of herd health planning (McElroy, 2012), identifying risk factors associated with bulk milk seropositivity would prove beneficial. Identification of such risk factors would also assist with promotion of biosecurity implementation (Villarroel et al, 2007) on Irish dairy farms which, at present, is sub-optimal (Sayers et al, 2012). The objective of this study therefore was to establish the association between general management and biosecurity-related practices, and bulk milk tank antibody status in unvaccinated herds in order to identify risk factors for exposure to Salmonella, N. caninum and L. hardjo in an extensive grazing production system.…”