Associations between bovine coronavirus and bovine respiratory syncytial virus infections and animal performance in Swedish dairy herds

摘要: To assess the economic impact of bovine coronavirus (BCV) and respiratory syncytial virus (BRSV) infections, accurate estimates their associated effects on animal performance are needed. This study aimed to quantify variation in individual test-day milk yield somatic cell count, risk reproductive failure after first service dairy cows, death calves heifers according BCV BRSV status herd. Three types were defined for based 1) dynamics over a 7-mo period BCV- BRSV-specific antibody levels pooled primiparous cows; 2) possible occurrence presumably BRSV-related clinical outbreaks; 3) combination both pieces information. A total 36,184 test days, 2,716 cows with service, 4,104 65 Swedish herds included analyses. Animal infections was quantified using hierarchical mixed generalized survival models, adjustment covariates known influence under study. significant reduction observed recently infected herds, as well having outbreak (of 0.57 0.91 kg/d, respectively), compared infection-free herds. There also increase count 12,000 cells/mL) located outbreak. The calf heifer, numerically higher BRSV-infected although this not statistically significant. In contrast, infection herd status, present study, significantly any production losses animals from those