RECOMMENDATIONS FOR RECORDING AND CALCULATING THE INCIDENCE OF SELECTED CLINICAL-DISEASES OF DAIRY-CATTLE

The report upon which the current discussion is based was prepared in response to the increasing interest of the dairy industry in the recor ding of clinical disease data. The major objective was to introduce gu idelines and standards for the recording and presentation of the disea ses of dairy cattle. Eight clinically identifiable diseases of economi c importance to the dairy industry were considered: milk fever, retain ed placenta, metritis, ketosis, left displaced abomasum, cystic ovaria n disease, lameness, and clinical mastitis. Standardized definitions f or these diseases were established through consultation with industry partners. Two approaches to summarization and reporting were proposed. For retrospective analysis, which is used when historical data are su mmarized for genetic evaluation for example, lactational incidence ris k (cumulative incidence) has Seen recommended. For current analysis, w hich is used for herd health monitoring, a true incidence rate has bee n recommended. Milk fever and retained placenta were exceptions to the latter because of their short periods of risk. For these two diseases , lactational incidence risks are reported.