Bovine Respiratory Disease Complex (BRDC): A review of lung lesions and reducing of quality of carcasses

Bovine respiratory disease complex (BRDC) is the biggest health problem of the cattle industry globally due to the high prevalence and economic consequences which arise due to numerous reasons. Huge economic losses are most often attributed to high morbidity and mortality, reduction of Average Daily Gain (ADG) and food utilization, weight loss, lower quality of carcasses and comprehensive measures of prophylaxis and therapy. BRDC commonly observed throughout the feedlot phase due to the stress factors. Predisposing factors divided didactic on environmental (inclement weather conditions, inadequate humidity and dust), host factors (age, sex, race, genetics, immune status) and stressful management practices (transportation, nutritional stress, metabolic disease, high density of animals, handling, castration, dehorning). In complex etiopathogenesis, in addition to the aforementioned predisposing factors, numerous viral and bacterial agents are involved. Gross lung lesions are most commonly observed in cattle slaughter or autopsies (visible to the naked eye) occur as a result of pneumonia. It is the result of an infection by the bovine respiratory syncytial virus (BRSV), parainfluenza virus type 3 (PI3V), bovine herpes virus type 1 (BoHV1) and bovine viral diarrhea virus (BVDV) alone or in combination with one another, as well the common bacterial pathogens Mannheimia haemolytica, Pasteurella multocida, Histophilus somni and Micrococcus spp. Numerous studies have pointed to the detrimental effects on performance and carcass characteristics.