Sanitary, environmental and nutritional management to reduce the incidence of bovine respiratory disease and the use of antibiotics in fattening beef cattle

Abstract

Bovine respiratory disease (BRD) is the main health problem in fattening beef cattle. Due to its multifactorial etiology, alternative strategies to reduce its incidence and correlated antimicrobial use must consider all the main critical aspects, related to sanitary, environment and nutritional management.
A multi-year project was set up to develop a specific integrated system to counteract the incidence of BRD, while reducing the use of antibiotics, and develop a risk-assessment sheet to evaluate, at the arrival, the potential sanitary risk of each single batch. During the first period (November 2019-September 2020), the effect of four vaccination protocols, differing for the route of administration, intramuscular (IM) versus intranasal (IN), was tested, as well as the effectiveness of a proper adaptation diet. In the second period (November 2020-May 2021), the best protocol merged was tested again, but shifting vaccination to day (d) 7 and improving environmental management and the biosecurity levels. During the entire project, blood samples and nasal swabs were taken at the arrival on a sample of animals to evaluate the circulation of pathogens and the presence of antibodies. Mortality, morbidity for BRD, relapses and antimicrobial consumption were evaluated, as well as the effect of the antimicrobial mass treatment based on the risk-assessment sheet.
The results of the first period highlighted a reduction of 29.1% in morbidity, of 81.7% in the first relapse and of 71.5% in the antimicrobial use (mg/PCU) where the IN vaccination was used in combination with a proper nutrition. In the second period, the delayed vaccination, in combination with improvement in environment conditions and biosecurity, has led to reduction of 49.3% in mortality, 41.9% in morbidity, 51.9% in first relapses and of 25.5% in antimicrobial use, compared with the same vaccination protocols in the first period. Comparing the health status in batches with and without antimicrobial treatment based on the risk assessment sheet, it appeared that mandatory avoiding it, even in case of evident risk, can be a damage for animal health, with increased morbidity, mortality and antimicrobial use.
In conclusion, an integrated and multidisciplinary approach, that consider both sanitary protocols, environmental and nutritional management, and antimicrobial treatment, in relation to an evident and clear sanitary risk, is essential to limit the BRD and the antibiotic consumption and to increase the welfare of newly arrived beef cattle.