The Cost-Benefit of Biosecurity
By Jean-Pierre Vaillancourt Department of Farm Animal Health & Resource Management College of Veterinary Medicine North Carolina State University Raleigh NCFeatures 100th anniversary Research Research
To determine the cost-benefit of a biosecurity system, one needs to juggle two types of information: facts about the economics associated with the type of production and the costs of implementing a biosecurity system; and estimates of the relative risk and cost of disease.
Many relatively inexpensive biosecurity measures may generate substantial benefits. Most are designed to control people access to the farm and to improve sanitation. However, these are dependent on compliance. The challenge is to convince all poultry personnel of the impact of their actions on the risk of breaking with an infectious disease. Education and communication are key factors in determining people’s perception of disease risks and, consequently, their assessment of the potential benefits of a biosecurity system.
In high density areas, a regional perspective is essential to the design of a biosecurity system, mainly in the face of an epidemic. Hence, the challenge for today’s poultry industry is to determine the cost-benefit in partnership with regional competitors.
Infectious diseases have always been a limiting factor in commercial poultry production. The scientific community has responded fairly successfully by producing effective vaccines for conditions such as Marek’s disease, hemorrhagic enteritis, Newcastle, infectious bronchitis, etc. However, even when vaccines exist, diseases remain costly; in particular in a global market economy where they can be used as trade barriers.
In the United States, the vertical integration of the industry has produced large efficient multi-site complexes designed to enhance productivity and reduce production costs. This model has been very successful economically. However, over the past few years, it has been challenged by emerging and reemerging infectious diseases. For example, several outbreaks of infectious laryngotracheitis and of mycoplasmosis have been reported. Poult enteritis mortality syndrome (PEMS) has had a devastating effect on the turkey industry in the South East United States. Turkey coronavirus enteritis (TCE) is still very much prevalent in the eastern part of North Carolina. In the northeast and the south, many industry people and health officials have expressed concerns over the presence of Avian Influenza in live bird markets.
These public health and production concerns need to be addressed. Biosecurity should certainly be the corner- stone of any long-term response to disease aggression. However, given the concentration of farms in certain areas, such concerns cannot be addressed solely by on-farm biosecurity.
A regional perspective is needed, and should be part of a biosecurity system. How do you determine the cost-benefit of such a system? This is not an easy question to answer. Preventing the occurrence of a given disease on a given farm cannot be, without a doubt, attributed to a specific set of biosecurity rules. In other words, you do not know for sure whether your biosecurity system is truly effective or whether the flocks on your farm have simply not been at risk. It is also true that the most stringent biosecurity system does not offer an absolute protection against diseases. Rossigneux (1998) suggests that the word biosecurity is indeed misleading because security implies the absence of danger (i.e., infection), which is probably never achieved under field conditions. So, to answer this question, one needs to juggle with two types of information: facts about the economics associated with the type of production and the costs of implementing a biosecurity system; and estimates of the relative risk and cost of disease.
Economic models developed to assess the value of biosecurity systems suggest that prevention of disease in the end is always less expensive than treatment (Morris, 1995). Gifford et al. (1987), working on a model for broiler breeders, confirmed “that expenditure on protective measures can be justified by both the risk of introducing a disease and the magnitude of losses that may occur following infection”. On a broiler breeder farm, the benefit-cost ratio of biosecurity is at least three for a farm considered at a 30% risk of being infected by an agent causing a severe disease. In the case of the most pathogenic conditions, they found that investment in biosecurity was justified even with a 0.01 probability of outbreak. However, the challenge in assessing the cost-benefit of a specific biosecurity measure is to contrast the resulting investment with other potential ventures. For example, adding an automatic gate to limit access to a breeder flock (with automatic recording of visitors and times) may represent a $13,500 investment. These funds could potentially also be used to purchase a piece of equipment that could immediately reduce the number of people required for a specific task, providing an immediate and easily quantifiable return on investment. However, the potential benefits in both cases should be assessed over the projected life of the equipment, considering the magnitude of the savings if this gate contributes to the prevention of a serious disease. In this case, of course, the return would be very high, but so may be the degree of uncertainty that this preventive measure will be effective.
Estimating the Risk of Disease
Estimating the risk of disease is also partly a subjective exercise. However, substantial evidence has been reported regarding major risks such as:
- Poor farm location: farm located in high density region (other farms within 2 km of premises);
- Introduction of birds of unknown origin;
- Introduction of contaminated material or infected birds;
- Presence of an infectious disease of interest in a region;
- Presence of this disease in neighbouring farms;
- Pest infestation (rodents and/or insects);
- Poor sanitation;
- No restrictions or requirements for visitors (i.e., high on-farm traffic, including hired help going from farm to farm);
These are common sense hazards that must be considered when estimating the risk of disease transmission. Although self evident, these risks are often ignored in practice. A similar situation exists in human medicine where significant health risk and protective factors are often neglected by patients. In the 1950’s, the United States Public Health Service developed the Health Believe Model to explain such behavior (Rosenstock, 1974). This model proposes that health risk assessment is determined by the individual’s perception of:
- His level of personal susceptibility to the particular disease;
- The degree of disability that might result from contracting this condition;
- The health action’s potential efficacy in preventing or reducing susceptibility or severity;
- Physical, psychological, financial barriers or costs related to compliance.
This model may very well apply to a grower’s perception of risk for his flock. One can also assume that this belief model pertains to the decision-making process of managers of integrated companies, shaping their appreciation of risks and of biosecurity measures. One supportive evidence is the fact that a similar proportion of poultry people comply with biosecurity measures as the general population does for disease prevention strategies designed to help them (Vaillancourt, unpublished data).
Table 2 offers an assessment of relative risk and of potential benefits based on the literature and on personal experience (Biosecurity in the poultry industry, 1995; Rossigneux, 1998; Wojcinski, 1993; Chiu, 1988). Of this list of usual suspects, one should consider in particular the following risks: poor employee training; lack of communication; lack of incentives for people associated with the farm; absence of a regional perspective; no auditing, and poor record keeping of the biosecurity system.
Assuming that Table 2 offers a valid assessment, it highlights the fact that many relatively inexpensive biosecurity measures may generate substantial benefits. Most are measures designed to control people access to the farm and to improve sanitation. However, these are dependent on compliance. In high density areas, a regional perspective is essential to the design of a biosecurity system, mainly in the face of an epidemic.
The cost-benefit assessment of biosecurity measures is determined by people’s perception of the level of risk to which they and their birds are exposed. This will also determine their degree of compliance with biosecurity measures.
The challenge is to convince all poultry personnel of the impact of their actions on the risk of breaking with an infectious disease. Education and communication are key factors in determining people’s perception of disease risks and, consequently, their assessment of the potential benefits of a biosecurity system.
Facts and Figures
Disease: Fowl Cholera
Type of Production: Commercial turkeys
Cost: $0.59/bird, $0.02/kg
Carpenter, et al. 1988
Disease: Reovirus infection
Type of Production: Broiler breeders
Disease: Influenza (nonpathogenic)
Type of Production: Egg layers, Pullets, Commercial turkeys
Cost: $1.67 to $2.94/bird, $5.05/bird, $5.83/bird
Disease: Influenza (Highly pathogenic)
Type of Production: Chickens
$6.06/bird (government expenses only), $19/bird (cost to industry)
Disease: Mycoplasma Gallisepticum
Type of Production: Egg layers
Disease: Coronavirus infection
Type of Production: Commercial turkeys
Rives, and Crumpler 1998
The estimated cost to the industry of the 1983-1984 Influenza outbreak in Pennsylvania based on the reported cost ($329 million in 2000 US dollars) published in a state extension document.
Procedures and Benefits
Partial list of biosecurity procedures and their relative cost independently of potential benefits ($$$ = very expensive; $$ = expensive; $ = inexpensive; ¢ = virtually no cost) and potential benefits (+++ = High; ++ = moderate; + = minimal)
Isolation (distance) from other farms and feedmill, slaughter plant, etc. $$$; +++; difficult to control over time.
Disposal of used litter away from all farms: $$; +++; difficult in high density regions.
Serologic monitoring: $$; +++; essential for regional level and farm level.
All-in, all-out production: $$; +++.
Introduction of new birds of known health status only:$; +++
Fence around premises: $$$;++
Gate at entrance of farm:$$; +++
Cost depends on quality; potential benefit dependents on compliance.
Sign advising to stay off farm if no authorization to enter:¢;+.
Parking area away from poultry barns: ¢; ++.
Requirements before a vehicle can enter:¢; +++.
Wash station for vehicles: $$; +++.
Use of locks for each poultry house: ¢; +++.
Dead bird disposal on farm: $$; +++.
Composting litter before removal: $; +++.
Removing litter after each flock: $$; +++
Downtime between flocks of at least 2 weeks: $; +++; can be expensive if much longer than 2 weeks but substantial benefits.
Pest control (rodents and insects):$; +++.
Access restricted if visitors
have been in contact with poultry: ¢; ++.
Shower in, shower out facilities: $$$; +++.
Coveralls provided by farm or requirement to wear clean coveralls: $; +++.
Clean rubber boots for all people on farm: $; +++.
Plastic boots for visitors: ¢; ++.
Changing clothing for employees leaving and returning to the farm on the same day: ¢; +++.
Auditing biosecurity rules: $; +++; compliance is critical for a biosecurity system.
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