Effect of on-arrival BRD vaccination on ultrasound confirmed pneumonia and production parameters in male dairy calves: a randomized clinical trial

The high degree of commingling and accumulation stressors during after transport makes prevention bovine respiratory disease (BRD) extremely challenging in the veal dairy beef industry. Upon arrival, vaccination for agents involved BRD is practically most achievable, but its efficacy under such conditions calves unknown. Given prevalence subclinical pneumonia these settings, primary objective present study was to determine effect 2 protocols administered upon arrival against syncytial virus (BRSV), parainfluenza type 3 (BPI-3) Mannheimia haemolytica on clinical lung ultrasonographic findings calves. In addition, effects average daily live weight gain cold carcass were determined. this randomized trial, 443 male assigned one groups: a negative, placebo-controlled group (NC) (n = 151), with subcutaneous injections 4 weeks apart an inactivated vaccine containing BRSV, BPI-3 M. (parenteral (PE) group) 149) second receiving intranasal live-attenuated BRSV vaccinations same as PE (intranasal-parenteral (IN/PE) 143). Clinical scoring quick thoracic ultrasonography (qTUS) performed all (wk 0), at peak (outbreak) 1), end first antimicrobial treatment 3) long-term evaluation point 10). Culture nanopore-sequencing non-endoscopic broncho-alveolar lavage (nBAL) samples used identify pathogens outbreak. 15.1% had consolidation ≥1cm incidence quickly rose 42.8% both IN-PE group, odds wk 10 reduced by 62% (odds ratio (OR) 0.38; 95% confidence interval (CI) 0.23–0.64) 41% (OR 0.59; CI 0.37–0.96), respectively. Short-term cure rate (50.3%), determined immediately treatment, not influenced vaccination. contrast, rate, 10, affected higher compared control (69.4% vs 51.2%; OR 2.2; 1.1–5.0). ADG production Vaccination resulted increase 3.5 4.3 kg (95% −0.9–7.9) −0.17–8.7), conclusion, study, production, likely caused improved secondary infections new cases between outbreak evaluation. protocol, using qTUS detection nBAL diagnostics pathogen identification adds dimension trials