Applied epidemiology: another tool in dairy herd health programs?

Data bases of herd health programs concern data from individual animals mainly. Several parameters that determine herd performance can be calculated from these programs, and by comparing actual values with standard values, areas for further improvement of health (and production) can be advised. However, such advice is usually not backed up by the proper statistical analyses. Moreover, data concerning the environment of the animals are not present and hence advice concerning multifactorial diseases are based on common knowledge and experience. Veterinary epidemiology offers methods that might improve the value of herd health programs by identification and quantification of factors and conditions contributing to multifactorial disease occurrence. Implementation of these methods within herd health programs will lead to more scientifically sound advice.