Problem of Respiratory Diseases in Cattle

**17**

**Chapter 2**

Approaches

*Samat Amat*

**Abstract**

Bovine Respiratory Disease in

Feedlot Cattle: Antimicrobial

Bacterial Pathogens and

Alternative Antimicrobial

Resistance in Bovine Respiratory

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.

antimicrobial alternatives, feedlot cattle

**1. Introduction**

**Keywords:** bovine respiratory disease, bacterial pathogens, antimicrobial resistance,

Cattle production is one of the important industries in North America, accounting for \$78.2 billion (US) and \$10.5 billion (Canada) in cash receipts during 2015. A substantial part of this economic benefit is derived from beef sector, where 10.6 and 2.5 million head of cattle and calves in the USA and Canada, respectively, were slaughtered for the beef market in 2015 [1, 2]. The number of beef cattle in the North American farms and ranches will continue to increase over the next decade
