Bovine respiratory disease during the mid-portion of the feeding period: Observations from vaccination history, viral and bacterial prevalence, and rate of gain in feedlot cattle

Abstract

The objective of this research was to provide preliminary observations related to bovine respiratory disease (BRD) morbidity in high-performing cattle related to cow-calf operations, number of vaccines received before the feedlot, viral and bacterial presence in the nasal cavity during the mid-feeding period, and rate of gain related to incidence of BRD. Health outcomes were evaluated from 4,346 cattle. Cattle were evaluated by the number of modified-live-viral, Mannheimia haemolytica, Histophilus somni, or Clostridiaspp. vaccines administered before feedlot entry. Individual animal rate of gain was evaluated by incidence of BRD. Nasal swabs were collected from BRD cases and controls to evaluate presence of viruses and bacteria. First treatment for BRD was associated with the number of times cattle received modified-live-viral vaccines before the feedlot (P = 0.02). Cattle administered a modified-live-viral vaccine 3 times before the feedlot had a greater first treatment for BRD (21.32%) compared with cattle vaccinated 1 time (9.56%; P = 0.06). Cattle that developed BRD had lower (P < 0.01) ADG through the first 30 d on feed compared with clinically healthy cattle. Preliminary nasal swab PCR results show common respiratory viral or bacterial pathogens were not identified in BRD during the mid-feeding period. There is great variability in BRD morbidity among cow-calf operations. A greater number of vaccinations administered before the feedlot was detrimental to health outcomes. Additional research is needed to further evaluate the entire host, environment, and pathogen triad for development of BRD.