Mortality in farmed mink: Systematic collection versus arbitrary submissions for diagnostic investigation

The distribution of diagnoses of mortality in mink submitted to the Danish Veterinary Laboratory (DVL) for diagnostic investigation in the calendar ye ar 1997 was compared with the diagnoses of mortality in all dead mink colle cted at 4 selected farms (project farms) during the same period. A total of 1,015 submitted mink and 1,149 mink from the 4 project farms were subjecte d to post mortem investigation. The average size (breeding stock) of the pr oject farms was larger than Danish farms on average. However, the distribut ion of colour types of the mink was comparable. The seasonal distribution o f the material from project farms and that of the submissions were approxim ately the same. Differences in the distribution of diagnoses as well as rec overed microorganisms were found however, mainly related to the proportion of gastro-intestinal disorders and E. coli respectively. These proportions were negatively correlated. Overall the results showed that extrapolating d iagnostic results of laboratory submissions to the population of farmed min k may be problematic, and more reliable methods for disease surveillance mu st be considered.