Intensively farmed animals such as pigs,cattle in feedlots and poultry,are continuously subjected to high nutritional,metabolic,environmental and social stressors that impact upon growth performance and increase susceptibility to disease.Consequently,it has been common practise for decades to include antimicrobial growth promotants or stimulants as a prophylactic means of preventing disease onset.Unfortunately,this not only enhances the development of direct and bystander antimicrobial resistances in pathogens but also within the endogenous commensal community.