Factors Affecting the Development of Bovine Respiratory Disease: A Cross-Sectional Study in Beef Steers Shipped From France to Italy

Bovine respiratory disease (BRD) is a complex, multifactorial syndrome and one of the major welfare economical concerns for cattle industry. This 1-year cross-sectional study was aimed at documenting prevalence BRD-related pathogens clinical signs before after long journey identifying possible predisposition factors. Male Limousine beef steers ( n = 169) traveling from France to Italy were health checked sampled with Deep Nasopharyngeal Swabs (DNS) loading (T0) 4 days arrival (T1). Real-time quantitative PCR used quantify presence bovine viral diarrhea virus (BVDV), syncytial (BRSV), alphaherpesvirus 1 (BoHV-1), coronavirus (BCoV), adenovirus (BAdV), parainfluenza 3 (BPIV-3), Histophilus somni, Mannheimia haemolytica, Mycoplasma bovis , Pasteurella multocida . Weather conditions departure recorded, travel taken documentation. At T0, even if no animals displayed signs, some them already positive or more pathogens. T1, number displaying BCoV, BAdV, BRSV, H. M. P. increased dramatically p < 0.001). Transport also significantly co-infection passing 16.0% T0 82.8% T1 An extra stop during seemed favor haemolytica 0.05). conditions, in particular sudden climate changes daily temperature variance, found be predisposing factors many The farm played role somni BCoV dramatically, but associations confirming that it spreads easily transport phases. Our findings our understanding increasing likelihood shedding can useful minimize incidence BRD implement animal regulations.