Modern techniques for monitoring high‐producing dairy cows 1. Principles of herd‐level diagnoses

THIS article, the first of two describing common practices used to monitor high‐producing dairy herds in North America, focuses on how to obtain herd‐level diagnoses using one‐time assessment of herd performance instead of day‐to‐day cow and herd‐level monitoring. This can provide important information when troubleshooting a particular problem or undertaking ongoing periodic surveillance of management practices on dairy farms. The majority of the techniques discussed have been developed and refined by clinicians working in the Food Animal Production Medicine group at the School of Veterinary Medicine, University of Wisconsin‐Madison, using information collected from dairy herd problem investigations, on‐farm recording systems, blood, milk and urine samples, and information stored in the Dairy Herd Improvement Association (DHIA) database (the US equivalent of the National Milk Records). The article also outlines how herd health records and information obtained from the DHIA may be used to highlight subclinical production disease problems. Part 2, to be published in the next issue, will consider how these tools can be used to achieve a specific herd‐level diagnosis for ketosis, subacute ruminal acidosis and hypocalcaemia.