Bovine Respiratory Disease in Feedlot Cattle: Antimicrobial Resistance in Bovine Respiratory Bacterial Pathogens and Alternative Antimicrobial Approaches

Abstract

Bovine respiratory disease (BRD) is the leading cause of morbidity and mortality in feedlot cattle in North America. The BRD is a complex multifactorial disease because its onset depends on the interaction between number of factors including host, environment, management and viral and bacterial infectious agents. The main bacterial pathogens associated with BRD are Mannheimia haemolytica, Pasteurella multocida, Histophilus somni and Mycoplasma bovis. Treatment and prevention of BRD in the feedlots are aimed mainly at bacterial pathogens through antimicrobial use. Although antimicrobial use has increased, the prevalence of BRD has also increased potentially due to the emergence of multidrug-resistant bacterial pathogens, which poses a serious threat to both animal and public health and necessitates the development of alternative antimicrobial approaches to mitigate BRD pathogens in feedlot cattle. The objective of this chapter is to provide a brief overview of pathogenesis of BRD, to review the current status of antimicrobial resistance in bacterial pathogens associated with BRD, and to discuss the potential antimicrobial alternative strategies, including probiotic and essential oil (EO) approaches, to mitigate bovine respiratory pathogens in feedlot cattle.

Bovine Respiratory Disease Complex (Brd)

“…Despite of advances in veterinary medicine and animal welfare, the economic impact of cattle diseases on the livestock industry still remains important. Bovine respiratory disease complex (BRD) is one of the most important disease prevalent in both dairy and beef production farms (Amat 2019). BRD defines the cases of pneumonia associated with inflammation, consolidation, lung abscesses, and fibrosis caused by one or more infectious agents (Guterbock 2014).…”

“…It also negatively affects reproductive performance, milk yield, and carcass quality in the long term (McGuirk 2008). The economic effects of BRD increase with the severity of the disease and treatment practices (Amat 2019). It has been reported that the rate of antibiotic use, which has taken an important place in BRD control, is 91.9% (USDA 2010), and this may lead to an increase in drug-resistant bacterial strains (Woolums et al 2018).…”

Development of a Multiplex Real-Time PCR Assay for Predicting Macrolide and Tetracycline Resistance Associated with Bacterial Pathogens of Bovine Respiratory Disease

“…Bovine respiratory disease (BRD) is one of the most common and costly cattle diseases and affects 97% of feedlots, or 16% of cattle, with economic losses estimated to exceed 1 billion USD/year [ 1 , 2 ]. BRD is a disease complex with multiple contributing factors, including environment, viruses, bacteria, and the host [ 3 ].…”

“…Lung samples refer to lung tissues and abdominal fluid clinical samples; nasal samples are collected as nasal swabs; other samples are either skin or liver tissues; missing samples are those lacking records about tissue types 2. The distribution of the samples by the pathogens is not exclusive, as more than one pathogen can be isolated from a single sample.…”

“…"R" indicated by the gold-standard test refers to samples containing pathogens resistant (R) or intermediate resistant (I) to antibiotics tested ("resistant" or R+I); hence classification given qPCR results based on the comparison to the gold-standard test also refers to the redefined "resistant" in this study 2. S indicated by both the gold-standard test and qPCR assay refers to samples containing pathogens susceptible to antibiotics tested 3.…”