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Field trials of a bovine respiratory syncytial virus vaccine.
A vaccine against bovine respiratory syncytial virus (BRSV: Norden), a cause of pulmonary edema-emphysema and pneumonia in calves, was evaluated in field trials on western Nebraska beef calves at branding, preweaning, weaning and postweaning. Of calves with undifferentiated respiratory infection at weaning, 20.9% of 2-dose vaccinates (169/810) and 27.5% of 1-dose vaccinates (230/837) required treatment, vs 48.2% of unvaccinated controls (397/823). At postweaning, 2.4% of 2-dose vaccinates (13/548) and 4.7% of 1-dose vaccinates (28/598) required treatment, vs 20.5% of controls (181/885). Studies in the 2 subsequent years revealed 11.3% of calves vaccinated at preweaning (263/2312) required treatment, vs 24.4% of controls (387/1587). Average costs from respiratory disease in 5 herds ranged from $12.83/head to $46.99/head before BRSV vaccination and 4/head to 54/head after vaccination.
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