THE NATIONAL ANIMAL HEALTH MONITORING-SYSTEM IN MICHIGAN .1. DESIGN, DATA AND FREQUENCIES OF SELECTED DAIRY-CATTLE DISEASES

A National Animal Health Monitoring System (NAHMS) in Michigan was started in 1986 to develop statistically valid data for use in estimating disease frequencies in dairy cattle, and the associated costs. The objectives of this paper are to: (1) describe what was done to implement and maintain the system in Michigan; (2) present selected disease frequencies; (3) discuss the epidemiological considerations of what was done and implications for the results obtained. Veterinary medical officers (VMOs - veterinarians from the university, state and federal governments) served as data collectors. After several sessions of training in current disease and management problems of dairy cattle, interview techniques, sampling methods, and data collection instruments, the VMOs participated in selection of the sample herds and data gathering. Sixty (n=60) of 6012 dairy herds were selected randomly and the VMOs visited the farms once a month for 12 months to collect management, disease, inventory, production, preventive treatment, financial and any other relevant data. Strict data quality control devices were used. Specific feedback and morale-boosting techniques were developed for the producers and data collectors. Of the three age groups studied, cows had the greatest number of disease problems. The six disorders found most frequently were (from highest to lowest) breeding problems, clinical mastitis, birth problems, metabolic problems, gastrointestinal problems, and lameness. In young stock, respiratory, multiple system, breeding, gastrointestinal, lameness, and birth problems were predominant, whereas in calves, gastrointestinal, respiratory, multiple system, lameness, metabolic/nutritional, and urogenital disorders were the major problems. © 1990.