N G One factor perhaps more than any other has underpinned the development of factory farming and that is the routine use of antibiotics.
Antibiotics are, in effect, being used as a substitute for good husbandry and hygiene.
In theory one may distinguish between those antibiotics which are used for growth promotion and those used for prophylactic purposes. In practice the distinction is blurred as antibiotics used as growth promoters also help prevent disease. What is clear is that, without the routine use of antibiotics, factory farming could not survive as infectious disease would overwhelm many intensive livestock units. The World Health Organisation has stressed that resistant strains of four bacteria which cause disease in humans have now been transmitted from animals to people. These are salmonella, campylobacter, enterococci and E.coli.