United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

Veterinary Services 

Centers for Epidemiology and Animal Health March 2008 

_________________________________________________________________________________________________________________________ 

Disease Prevention, Treatment 

Practices, and Antibiotic 

Administration Techniques on 

U.S. Swine Sites 

In 2006, the USDA’s National Animal Health Monitoring 

System (NAHMS) conducted a study on swine health 

and management practices from a random sample of 

swine production sites in 17 States*. These sites 

represented 94 percent of the U.S. pig inventory and 94 

percent of U.S. pork producers with 100 or more pigs. 

Disease prevention and treatment practices

In addition to vaccinating for certain pathogens, sites 

often use treatment regimens of treatments to prevent 

and control disease at certain management phases. 

From June through November 2006, 74.7 percent of 

sites dewormed sows and gilts and 64.0 percent 

dewormed boars, which accounted for 60.2 percent of 

total sows and gilts and 67.8 percent of total boars 

(table 1). 

 In preweaned piglets, administration of iron was the 

most common preventive practice (82.1 percent of sites). 

About 9 of 10 piglets (92.3 percent) were on sites that 

administered iron at or before weaning. Over 4 of 10 

sites (43.5 percent) gave preweaned piglets antibiotics in 

feed, but fewer than 1 in 10 piglets (8.7 percent) were on 

sites that administered antibiotics in feed to piglets. 

 Over 8 of 10 sites (85.3 percent) used antibiotics in 

feed for nursery pigs, and more than 9 of 10 of nursery 

pigs (94.9 percent) were on these sites. The use of 

antibiotics in feed was a more common preventive 

practice in nursery and grower/finisher pigs than in 

breeding animals and piglets. 

_______________________ 

*States 

Arkansas, Colorado, Illinois, Indiana, Iowa, Kansas, Michigan, 

Minnesota, Missouri, Nebraska, North Carolina, Ohio, Oklahoma, 

Pennsylvania, South Dakota Texas, and Wisconsin. 

Table 1. For Sites with the Specified Pig Types, 

Percentage of Sites (and Percentage of Pigs on 

These Sites) that Regularly Gave the Following 

Treatments from June through November 2006

Percent Sites 

 Pig Type 

Sows/ 

Gilts Boars Piglets*

Nursery Grower/

Finisher

Practice Pct. Pct. Pct. Pct. Pct. 

Deworm 74.7 64.0 30.0 33.4 30.6 

Mange/lice 

treatment 46.5 43.5 23.0 24.4 12.7 

Iron NA NA 82.1 NA NA 

Antibiotics 

in feed 47.4 37.2 43.5 85.3 81.2 

Antibiotics 

in water 3.3 1.3 7.6 40.4 38.6 

Antibiotics (oral) 5.0 4.8 14.9 4.2 2.8 

Antibiotics 

(injection) 47.9 27.5 54.9 53.8 56.6 

Percent Pigs 

Deworm 60.2 67.8 3.5 5.2 13.3 

Mange/lice 

treatment 13.4 44.7 1.3 2.3 3.1 

Iron NA NA 92.3 NA NA 

Antibiotics 

in feed 38.8 30.7 8.7 94.9 86.4 

Antibiotics 

in water 2.7 0.5 2.6 76.2 65.7 

Antibiotics (oral) 4.7 3.1 41.5 5.1 5.2 

Antibiotics 

(injection) 35.6 21.2 85.6 76.4 68.4 

*Before or at weaning 

Antimicrobial administration techniques 

 From June through November 2006, 38.5 percent of 

sites gave breeding females occasional short-term 

treatments via injections of antimicrobials. Injections 

were rarely used for occasional short-term prevention 

(pulse dosing), except for piglets, where 18.8 percent of 

sites used did use injections. 

 About one-third of sites delivered antimicrobials via 

injection to breeding females, piglets, nursery pigs and 
United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

grower/finisher pigs as an occasional short-term 

treatment. 

 For nursery pigs, 53.8 percent of sites administered 

antimicrobials in feed continuously, while 32.8 percent of 

sites did so for grower/finisher pigs. Nearly three times 

as many sites delivered antimicrobials in feed to 

breeding females as an occasional short-term prevention 

of disease using pulse dosing compared with giving 

antimicrobials continuously in feed (30.7 and 10.8 

percent of sites, respectively). Conversely, for piglets, 

about one-fifth as many sites delivered antimicrobials in 

feed to piglets as an occasional short- term prevention of 

disease using pulse dosing compared with giving 

antimicrobials continuously in feed (6.0 and 28.4 percent 

of sites, respectively) [table 2]. 

Table 2. For Sites with the Specified Pig Types, 

Percentage of Sites that Used Antimicrobials in 

Feed, Water, or by Injection from June through 

November 2006, by Route of Administration and by 

Treatment Type 

Complete descriptive reports and other information 

sheets from NAHMS Swine Studies are available at: 

http://nahms.aphis.usda.gov 

For more information, contact: 

USDA–APHIS–VS, CEAH 

NRRC Building B, M.S. 2E7 

2150 Centre Avenue 

Fort Collins, CO 80526-8117 

970.494.7000 

E-mail: NAHMS@aphis.usda.gov 

http://nahms.aphis.usda.gov 

#N513.0308 

____________________________________ 

The U.S. Department of Agriculture (USDA) prohibits discrimination in 

all its programs and activities on the basis of race, color, national 

origin, age, disability, and where applicable, sex, marital status, familial 

status, parental status, religion, sexual orientation, genetic information, 

political beliefs, reprisal, or because all or part of an individual’s income 

is derived from any public assistance program. (Not all prohibited 

bases apply to all programs.) Persons with disabilities who require 

alternative means for communication of program information (Braille, 

large print, audiotape, etc.) should contact USDA’s TARGET Center at 

(202) 720–2600 (voice and TDD). To file a complaint of 

discrimination, write to USDA, Director, Office of Civil 

Rights, 1400 Independence Avenue, S.W., Washington, 

D.C. 20250–9410, or call (800) 795–3272 (voice) or (202) 

720–6382 (TDD). USDA is an equal opportunity provider 

and employer. 

 Percent Sites 

 Treatment Type 

 Occasional 

Short-term 

Treatment 

Occasional 

Short-term 

Prevention* 

Occasional 

Individuals 

or Groups 

Continuously 

Pig Type Route Percent Percent Percent Percent 

Breeding 

females Feed 17.3 30.7 7.0 10.8 

 Water 6.8 2.4 3.0 0.1 

 Injection 38.5 4.5 35.7 NA 

Boars Feed 10.3 15.6 6.1 9.8 

 Water 3.6 0.1 3.2 0.1 

 Injection 18.6 1.9 26.1 NA 

Piglets Feed 14.7 6.0 4.2 28.4 

 Water 6.7 8.2 3.5 0.9 

 Injection 37.3 18.8 39.9 NA 

Feed 11.8 34.2 2.1 53.8 

Water 32.9 21.6 9.0 0.7 Nurseryage pigs 

Injection 31.2 4.4 42.6 NA 

Feed 31.1 37.8 8.6 32.8 

Water 41.7 9.2 10.8 0.1 

Grower/ 

finisher 

pigs Injection 30.6 0.6 49.5 NA 

*Pulse dosing. Increases antibiotic levels in an animal early in the dosing interval, 

followed by a dose-free period in which antibiotic levels are allowed to diminish 

until the next dose.