Quantity of Antimicrobials Used in Food Animals in the United States Charles M. Benbrook Consultant to the Union of Concerned Scientists 101st Annual Meeting American Society for Microbiology May 22, 2001

Released Jan. 8, 2001 Access text at:

METHODOLOGY F Use estimates developed for swine, beef cattle and broiler production F Reflects antimicrobial use in the mid- to late 1990s

METHODOLOGY Use Antimicrobial x = Number of animals treated x x Average days treated x x Average dose x

DATA SOURCES F Average number of animals produced annually in the late 1990s from USDA inventory data ; 29 million beef and veal calves ; 92.6 million hogs ; 7.8 billion chickens

DATA SOURCES F Percent of animals treated with different antibiotics by the USDA National Animal Health Monitoring System (NAHMS) and NAS reports F Data quality on extent of use better for beef and swine, less complete for poultry

METHODOLOGY F Developed antimicrobial use estimates during each major growth stage F Total feed consumed during each growth stage calculated from widely accepted estimates of feed efficiency and weight gain

METHODOLOGY F Antimicrobial use in each growth stage projected from NAHMS data and CFR Indications and ‘Conditions of Use’ in the FDA ‘Green Book’ F Days fed and average dose rates adjusted downward from maximum allowed based on common industry practice and expert advice

FINDINGS Beef and Veal Antimicrobial Use Estimated Antimicrobial Use in Pounds F Calves (birth -> 250 pounds) 45,511 F Beef ( pounds) 164,051 F Backgrounder ( pounds) 1,421,277 F Feedlot ( ,200 pounds) 2,055,237 F Veal Calves 6,941 Total Cattle Industry 3,693,017

FINDINGS Poultry Production Antimicrobial Use Estimated Antimicrobial Use in Pounds F Pre-starter & Starting 2,658,081 F Growing & Finishing 7,877,845 Total Poultry Industry 10,535,926

FINDINGS Swine Production Antimicrobial Use Estimated Antimicrobial Use in Pounds F Starting ( pounds) 1,254,943 F Feeding ( pounds) 1,757,249 F Finishing ( pounds) 7,279,080 F Breeding animals 57,324 Total Swine Industry 10,348,596

FINDINGS Total Annual Antimicrobial Use Total Use Percent (pounds) Total Use Beef3,693, % Swine 10,348, % Poultry 10,535, % 24,577,539

FINDINGS Trends in Antimicrobial Use per Animal 1985* Late 1990s Percent Change Beef 2,889,573 3,693,017 28% Swine 11,710,650 10,378, % Poultry 3,436,140 10,535, % 18,036,363 24,577, % * 1985 use assuming the number of beef cattle, swine, and poultry produced in 1984 equaled late 1990s herd/flock size.

FINDINGS Trends in Tetracycline Use per Animal 1985* Late 1990s Percent Change Beef 1,442, , % Swine 3,890,980 4,972,213 28% Poultry 485,667 1,418, % * 1985 use assuming the number of beef cattle, swine, and poultry produced in 1984 equaled late 1990s herd/flock size.

“Conventional Wisdom” Annual Estimates prior to ‘Hogging It’ Total use (per NAS) = 50 million pounds Total use in agriculture (per AHI) = 17.8 million pounds Total use in humans (calculated) = 32.2 million pounds PLACING USE INTO PERSPECTIVE

DATA SOURCES F 50 million total use extrapolated from 1985 IOM estimates, in turn based on very incomplete data F Legitimized through repetition; including on CDC website (until recently) F No basis in fact; a myth

METHODOLOGY Medical (Outpatient & Inpatient) Human Use Estimates based on: Number of courses of treatment times the average dose delivered

METHODOLOGY F 120 million courses of treatment F Two doses per day for 10 days F Dose rate between 250 & 500 mg F 5-10 grams of antimicrobial per course of treatment Outpatient Use Estimate

METHODOLOGY F 50 million courses of treatment F Average 8 days per course F 250 mg (low end) to 500 mg (high end) per dose Inpatient delivery (injection or IV) more efficient but average patient is also sicker, so same dose range as outpatient use Inpatient Use Estimate

FINDINGS Antimicrobials Used in Human Medicine Low End High End Most Likely Value Outpatient Use 1,322,774 2,645,547 2,100,000 Inpatient Use 551,156 1,102, ,000 Total Treatment 1,873,930 3,747,858 3,000,000 *Table 2, ‘Hogging It’, p. 17.

AHI 2000 Estimates Use Percent Total Animal Use Animal Therapeutic % and Disease Prevention Animal Growth Promotion % 17.8 million pounds Total Animal Use as Percent of 50 million = 36% Total Human Use as Percent of 50 million = 64% PLACING USE INTO PERSPECTIVE

UCS Estimates Total Percent Pounds Total Use Human Uses Inpatient 900,000 3% Outpatient 2,100,000 6% Total Disease Treatment 3,000,000 9% Other Human Use 1,500,000 4% All Human Uses 4,500,000 13% PLACING USE INTO PERSPECTIVE

Shares of Total Antimicrobial Use AHI UCS PLACING USE INTO PERSPECTIVE Conventional Wisdom Animal36% 84% Human Medicine64% 9% Other %

Non-Human Antimicrobial Use Total Percent Pounds Total Use Livestock Uses Non-therapeutic (3 species)24,600,000 70% Non-therapeutic (other) 3,000, % Therapeutic (all species) 2,000, % Pesticide Uses 50, % Companion Animals 1,000, % Total Non-Human Uses30,600,000 87% Human Use 4,500,000 Total Use 35,100,000 PLACING USE INTO PERSPECTIVE

CONCLUSIONS F Animal use accounts for the majority of total antimicrobial use F Pounds used in treating largely healthy (although stressed) animals exceeds human use about 8 to 1

FINDINGS 13 million pounds of antimicrobials used for nontherapeutic purposes in raising beef, swine and poultry are drugs that are no longer approved in Europe for such uses

FINDINGS Class I: Used to treat human disease, few or no alternatives Class II: Used to treat human disease, alternatives exist Class III: Not currently used to treat human disease Animal Uses of Antimicrobials by Importance in Treating Human Disease

FINDINGS Nontherapeutic Antimicrobial Uses in Livestock by Relative Importance in Treating Human Disease

FINDINGS Nontherapeutic Antimicrobial Uses in Livestock by Relative Importance in Treating Human Disease

FINDINGS Nontherapeutic Antimicrobial Uses in Livestock by Relative Importance in Treating Human Disease

RECOMMENDATIONS F FDA should require antimicrobial use data by species, class, disease, delivery system and treatment period

RECOMMENDATIONS F USDA should improve completeness and accuracy of periodic use surveys

RECOMMENDATIONS F Speed up Priority Action 5 -- establishment of usage monitoring and information sharing system