Calf health in cow-calf herds in Switzerland.

In 1993, an observational study was initiated to provide general information on animal health in extensive beef farms, to estimate disease frequency and the economic impact of calf diseases and to identify risk factors related to health and weight gain. The longitudinal study was conducted from fall 1993 until winter 94/95 and included 100 farms in western Switzerland. The basic concept was to follow one generation of calves on these farms and record all events concerning animal health from birth to weaning. The study population included 1270 calves (most were Angus crossbreds). Farm-management data were collected with a questionnaire conducted on the farm. Birth and weaning weights were obtained from the beef cattle breeding association. Clinical diagnoses and treatment costs were provided by the farm veterinarians. Two thirds of the dead calves were submitted to a complete postmortem examination. Fifty-three percent of the farms in the study were primary type income farms while 47% were secondary type income farms. Thirty-eight percent of the farms were situated in the lower areas of Switzerland, 14% in the prealpine foothills, the remaining 48% were located in mountain areas. Preweaning calf mortality was 5%. The main causes of calf deaths were respiratory diseases and digestive disorders. Twenty-two percent of the calves were treated at least once by a veterinarian; 36% of the treatments administered by the veterinarian were applied because of diarrhea, 27% because of respiratory diseases. Disease incidence was highest during the months of November, December and January. The association of disease and potential farm-level risk factors was analysed using chi 2-statistics and multivariable regression methods including generalized estimating equations to adjusted for herd effects. Specific risk factors for disease were not identified. Treatment for disease was not associated with 250-day standardized weight gain.