Assessing the economic impact of an endemic disease: the case of mastitis.

A large part of the world's resources are used to produce animal products. Efficient use of these resources is important to improve social well-being. Endemic animal diseases decrease production efficiency, because they require a higher level of input to produce the same amount of output or result in a lower output with the same amount of input. The optimal level of production with and without disease differs from farm to farm and depends on varying economic circumstances. Given these difficulties, making an accurate theoretical estimation of the economic impact of endemic diseases is challenging. Current approaches towards the economic assessment of endemic diseases are, therefore, quite pragmatic. For on-farm decision-making, the total costs consist of failure costs and preventive costs. Failure costs are associated with production losses (i.e. decreases in milk production, mortality and culling), treatment costs (i.e. veterinary treatment, drugs, and discarded milk) and the use of other resources associated with the occurrence of disease (i.e. increased labour costs). Preventive costs are associated with preventive measures in terms of equipment, consumables (e.g. diagnostics and chemicals) and the use of other resources to prevent diseases (i.e. increased labour). There is a substitution relationship between failure costs and preventive costs. That means that, in order to maximise profit at the farm level, the amount of resources invested in prevention should be chosen in such a way that total costs are minimised. The most studied endemic disease in animal production is mastitis. Most publications on mastitis only assess failure costs, and studies on assessing the total costs and best methods to determine an optimal level of prevention are scarce. Future challenges lie in researching frameworks that can assist decision-makers to establish optimal prevention levels for endemic diseases.