Quantity of Antimicrobials Used in Food Animals in the
United StatesCharles M. Benbrook
Consultant to theUnion of Concerned Scientists
101st Annual MeetingAmerican Society for Microbiology
May 22, 2001
Released Jan. 8, 2001
Access text at:
http://www.ucsusa.org
METHODOLOGY
Use estimates developed for swine, beef cattle and
broiler production
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
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
Percent of animals treated with different antibiotics by the USDA National Animal Health Monitoring System (NAHMS) and NAS reports
Data quality on extent of use better for beef and swine, less complete for poultry
METHODOLOGY
Developed antimicrobial use estimates during each major growth stage
Total feed consumed during each growth stage calculated from widely accepted estimates of feed efficiency and weight gain
METHODOLOGY
Antimicrobial use in each growth stage projected from NAHMS data and CFR Indications and ‘Conditions of Use’ in the FDA ‘Green Book’
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
Calves (birth -> 250 pounds) 45,511
Beef (250 - 500 pounds) 164,051
Backgrounder (500-700 pounds) 1,421,277
Feedlot (700 - 1,200 pounds) 2,055,237
Veal Calves 6,941
Total Cattle Industry 3,693,017
FINDINGS
Poultry Production Antimicrobial Use
Estimated Antimicrobial Use in Pounds
Pre-starter & Starting 2,658,081
Growing & Finishing 7,877,845
Total Poultry Industry
10,535,926
FINDINGS
Swine Production Antimicrobial Use
Estimated Antimicrobial Use in Pounds
Starting (15 - 40 pounds) 1,254,943
Feeding (40 - 100 pounds) 1,757,249
Finishing (100 - 240 pounds) 7,279,080
Breeding animals 57,324
Total Swine Industry
10,348,596
FINDINGS
Total Annual Antimicrobial Use
Total Use Percent(pounds) Total Use
Beef 3,693,017 15.0%
Swine 10,348,596 42.1%
Poultry 10,535,926 42.9%
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 10,378,596 -
11.6%
Poultry 3,436,140 10,535,926
307%
18,036,363 24,577,539 36.3%
* 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 1,442,780 731,520
-49%
Swine 3,890,980 4,972,213
28%
Poultry 485,667 1,418,675
192%
* 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
50 million total use extrapolated from 1985 IOM estimates, in turn based on very incomplete data
Legitimized through repetition; including on CDC website (until recently)
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
120 million courses of treatment
Two doses per day for 10 days
Dose rate between 250 & 500 mg
5-10 grams of antimicrobial per course of treatment
Outpatient Use Estimate
METHODOLOGY
50 million courses of treatment
Average 8 days per course
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 1,102,311
900,000
Total Treatment 1,873,930 3,747,858
3,000,000
*Table 2, ‘Hogging It’, p. 17.
AHI 2000 Estimates
Use Percent TotalAnimal Use
Animal Therapeutic 14.7 82.6%and Disease Prevention
Animal Growth Promotion 3.1 17.4%
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
Animal 36% 84%
Human Medicine 64% 9%
Other ----- 7%
Non-Human Antimicrobial Use Total Percent
Pounds Total UseLivestock Uses
Non-therapeutic (3 species) 24,600,000 70%
Non-therapeutic (other) 3,000,000 8.5%
Therapeutic (all species) 2,000,000 5.7%Pesticide Uses 50,000 0.1%Companion Animals 1,000,000 2.8%Total Non-Human Uses 30,600,000 87%Human Use 4,500,000Total Use 35,100,000
PLACING USE INTO PERSPECTIVE
CONCLUSIONS
Animal use accounts for the majority of total antimicrobial use
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
Cattle Swine Poultry TotalClass I 18,181 7,492 574,435 600,108 Class II 1,458,804 9,788,870 1,683,064 12,930,738 Class III 2,216,032 552,234 8,278,427 11,046,693
Total All Classes 3,693,017 10,348,596 10,535,926 24,577,539 Percent of Total 15% 42% 43%
FINDINGS
Nontherapeutic Antimicrobial Uses in Livestock by Relative
Importance in Treating Human Disease
Cattle Swine Poultry Total
Erythromycin 18,181 381,753 399,934 Virginiamycin 7,492 192,682 200,174 Total Class I 18,181 7,492 574,435 600,108Class I as % of Total 0.5% 0.1% 5% 2%
Class I: Used to Treat Human Disease, Few or No Alternatives
FINDINGS
Nontherapeutic Antimicrobial Uses in Livestock by Relative
Importance in Treating Human DiseaseCattle Swine Poultry Total
Chlortetracycline 588,042 4,007,632 1,418,675 6,014,349Bacitracin 25,885 1,894,450 96,728 2,017,063Tylosin 356,999 943,635 1,300,634Oxytetracycline 143,478 964,581 1,108,059Sulfathiazole 901,251 901,251Sulfamethazine 344,400 455,434 799,834
Penicillin 528,777 141,867 670,644
Lincomycin 53,685 25,794 79,479
Apramycin 39,425 39,425
Total Class II 1,458,804 9,788,870 1,683,064 12,930,738
Class I & II as % of Total 40.0% 95.0% 21% 55%
Class II: Used to Treat Human Disease, Alternatives Exist
RECOMMENDATIONS
FDA should require antimicrobial use data by species, class, disease, delivery system and treatment period
RECOMMENDATIONS
USDA should improve completeness and accuracy of periodic use surveys
RECOMMENDATIONS
Speed up Priority Action 5 -- establishment of usage monitoring and information sharing system