Too Much or Too Little: The Hazards of Mixing Antibiotics in the Feed Given to Food Animals

How food animals are given medication can be very different from how you take medication.  While humans are prescribed antibiotics at specific dosages in pills or injections, food animals are often given antibiotics mixed in their feed and freely choose how much to consume.  These free-choice medicated feeds (FCMF) make it difficult to deliver an intended or predictable dose of antibiotics to food animals. The result can be disastrous; under-administration of antibiotics leads to unresolved infections and contributes to the development of antimicrobial resistance, while over-administration can cause animal toxicity and increase drug residues in meat and milk.

A new commentary in Environmental Health Perspectives, lead authored by Dave Love, PhD, CLF’s project director of Aquaculture and Environmental Public Health, sheds light on the practice of administering antibiotics in FCMF. The Food and Drug Administration has approved 685 drugs for medicated feed, many of which are consumed on a free-choice basis, according to Dr. Love, who looked into the practice with co-authors Meghan Davis, DVM, MPH a CLF Pre-doctoral Fellow and Sommer Scholar, Anna Bassett, Lead Technical Auditor and Andrew Gunther, Program Director of Animal Welfare Approved, an organization which audits and certifies family farms on the basis of humane animal husbandry, and senior author Keeve Nachman, PhD, MHS, Director of CLF’s Farming for the Future Program.

Their commentary, “Dose Imprecision and Resistance: Free-Choice Medicated Feeds in Industrial Food Animal Production in the United States,” discusses the history of medicated feed, the nature of FCMF use, and its role in development of and selection for antimicrobial-resistant microorganisms. The commentary also discusses legislative efforts to address antimicrobial use in food animal production. Read More >