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# FDA Proposes ‘Biomass’ Way of Tracking Animal Antibiotics
- URL: https://www.fdaweb.com/fda-proposes-biomass-way-of-tracking-animal-antibiotics/
- Published: 2017-08-14T12:00:00.000Z
- Updated: 2026-09-14T22:40:55.000Z
- Author: David McFarland
- Tags: FDA Policy/General, #legacy-id-D5139371

FDA’s Center for Veterinary Medicine is proposing to use a “biomass indicator” to help it better analyze antimicrobial sales and food-animal population data it already receives. According to an [8/14 *CVM Update*](https://www.fda.gov/AnimalVeterinary/NewsEvents/CVMUpdates/ucm571091.htm?source=govdelivery&utm%5Fmedium=email&utm%5Fsource=govdelivery), a biomass denominator is the population of a given livestock population in the U.S. multiplied by the average weight of that species. Use of the proposed method “will help calculate estimates of annual antimicrobial drug sales adjusted for the size of the animal population (also known as the animal biomass) potentially being treated with those drugs.”

In the [proposal itself](https://www.fda.gov/downloads/AnimalVeterinary/SafetyHealth/AntimicrobialResistance/UCM571099.pdf?ref=fdaweb.com), the agency says it “intends to calculate a milligram per kilogram (mg/kg) value for at least the antimicrobial drug classes that are important in human medicine11 (e.g., aminoglycosides, cephalosporins, fluoroquinolones, lincosamides, macrolides, penicillins, sulfonamides, and tetracyclines).” It says CVM intends to calculate four biomass denominators, one for each of the four major food-producing species—cattle, swine, chickens, and turkeys.