Evaluation of mycobacterium cell wall fraction (MCWF) immune stimulant as antimicrobial alternative following administration to veal calves

Abstract

High levels of mortality in dairy calves is a significant welfare issue and a major source of economic losses. A preventative measure used to reduce mortality is antimicrobial incorporation into the milk or milk replacers. As a result of the abundant use of antimicrobials, high levels of antimicrobial resistant bacteria have been detected. With antimicrobial resistance becoming of greater concern worldwide, it is imperative to seek alternative treatment options. Mycobacterium cell wall fraction (MCWF), Amplimune™ (NovaVive Inc, Canada), is an immunostimulant licensed for treatment of infection caused by enterotoxigenic E. coli in young calves. In a recent study, application of MCWF on arrival in conjunction with metaphylactic treatment significantly reduced incidence and severity of respiratory and gastrointestinal clinical signs in veal calves. The main objective of the current study was to determine if MCWF could be used as a stand-alone preventive therapeutic administered on arrival. We hypothesized that, MCWF could be used as an antimicrobial alternative not only reducing mortality but also significantly reducing the incidence and severity of clinical conditions and consequently the number of antimicrobials used in the veal operations.