Serving Stakeholders

When questions arise about the health and management 

of livestock, poultry, and farmed aquatic animals in 

the United States, NAHMS often provides the answers. 

Through periodic national studies of these animals, 

NAHMS provides stakeholders in the private and public 

sectors with valuable information on disease occurrence 

and exposure to disease agents, management practices, 

productivity, knowledge gaps, and other important topics. 

These data support many information needs, including 

those below: • NAHMS data on producer 

biosecurity practices and 

animal movements (such 

as transport distances 

and frequencies) for mul-

tiple animal industries 

have been essential in 

establishing parameters 

for the North American 

Animal Disease Spread 

Model, which simulates 

the spread and control of 

highly contagious diseases 

in susceptible animals. 

• After hurricanes Katrina 

and Rita damaged or destroyed catfish ponds, 

NAHMS data documenting producers’ standard 

practices for draining and reconstructing ponds were 

used to provide an objective basis for calculating 

requests for Federal assistance.

• Trend data collected between 1990 and 2006 by four 

NAHMS swine studies documented the decline and 

virtual elimination of trichinae in commercial market 

swine and showed a corresponding decrease in the use 

of production practices that contribute to trichinae 

infection (such as feeding uncooked food waste 

to swine). 

What Is NAHMS?

NAHMS is a program that conducts national studies by 

combining the efforts of multiple government agencies, 

producers and other industry representatives, academic 

institutions, and public- and animal-health professionals. 

These efforts are organized by a multidisciplinary group 

within the Centers for Epidemiology and Animal Health, 

a program within the U.S. Department of Agriculture 

(USDA), Animal and Plant Health Inspection Service 

(APHIS). This group is composed of veterinary epidemi-

ologists, livestock commodity specialists, statisticians, a 

trade economist, a technical communicator, and technical 

support staff. 

What Is a NAHMS 

National Study?

A national study generally focuses on one animal com-

modity or production type (such as swine production or 

beef cow-calf operations). The study typically consists of 

one or more questionnaires and might include collection 

of biological samples (such as blood, feces, milk, feed) 

related to the study objectives. To be considered national 

in scope, each study is designed to include the States 

that represent at least 70 percent of the targeted animal 

population and at least 70 percent of operations with the 

targeted animal in the United States. A study typically 

includes fewer than 25 States, enabling more efficient 

use of resources.

The interval 

between stud-

ies for each 

commodity 

or production 

type depends 

on information 

needs. In gen-

eral, swine, dairy, 

beef, and poultry 

commodities are 

National Animal Health Monitoring System (NAHMS) 

national studies provide essential 

information on livestock and 

poultry health and management 

to decisionmakers, including 

producers, researchers, and 

policymakers. Each animal 

group is studied at regular 

intervals, providing up-to-date 

and trend information needed to 

monitor animal health, support 

trade decisions, assess research 

and product development needs, 

answer questions for consumers, 

and set policy.

Collecting 

Vital Information 

on Animal 

Health

studied about every 5 years, 

while other commodities are 

studied at longer intervals. 

Since 1990, NAHMS has 

conducted multiple national 

studies of the following 

commodity groups: • Swine (1990, 1995, 2000, 

and 2006)

• Dairy (1991–92, 1996, 

2002, and 2007)

• 	Beef cow-calf (1992–93, 

1997, and 2007–08)

• Beef feedlot (1994 and 

1999)

• Poultry (1999, 2004, 

and 2010)

• Sheep (1996 and 2001) 

and goats (2009)

• Catfish (1997, 2003, 

and 2010) 

• Horses and other equids

(1998 and 2005)

What Is the 

Study Process?

From initial planning to full reporting of results, each 

study takes about 4 years. A new study begins roughly 

every year, so several studies are in progress at any time. 

The cycle for each study consists of the following five 

general phases:

1. Information needs assessment. To help focus 

the study and define the priority objectives, 

stakeholders from industry, academia, Federal 

and State governmental agencies, and public- and 

animal-health organizations provide input to 

identify critical information gaps in animal health 

and management. 

Origin of NAHMS

The need for accurate agricultural information has been formally 

recognized since 1884, when 

the Animal Industry Act directed 

the Bureau of Animal Industry 

(now APHIS) to collect informa-

tion that would be “valuable to 

the agricultural and commercial 

interests of the country.” In 

the mid-1970s, the National 

Academy of Sciences called 

for greater efforts to meet the 

information needs of producers, 

veterinarians, academics, edu-

cators, and government policymakers. Subsequently, NAHMS 

was formed and, by 1990, began 

studying the Nation’s livestock, 

poultry, and farmed aquatic 

animals. NAHMS provides 

the science-based, statistically 

sound information essential to 

decisionmaking.

USDA, R. Anson Eaglin

USDA, R. Anson Eaglin
The U.S. Department of Agriculture 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.

Issued April 2010

Program Aid No. 2039

2. Questionnaire 

development and 

sampling design. 

Questionnaires are 

written and pretested 

to ensure that they 

will capture the data 

needed to fulfill the 

study’s objectives 

and yield thorough, 

accurate information.

NAHMS works with USDA’s National Agricultural 

Statistics Service (NASS) to randomly select 

operations by size for potential participation 

and to ensure that they accurately and precisely 

represent the targeted national livestock and 

poultry populations.

3. Field implementation. 

After specific training, 

NASS personnel con-

tact selected producers 

to complete the ques-

tionnaire. If the study 

includes additional 

components, interested 

producers provide 

written consent allowing Federal and State animalhealth personnel to contact them about continuing 

in the study. Questionnaires are usually completed 

during in-person interviews. If the study includes 

biological sampling, 

animal-health profession-

als and/or the producers 

themselves collect and 

ship the samples to desig-

nated veterinary diagnostic 

laboratories. Producers 

then receive results of 

biological sample testing. 

Participation in NAHMS national studies is volun-

tary, and producer identities and the data are treated 

as confidential business information. No informa-

tion is released that would enable the identification 

of individual producers. 

4. Data validation 

and analysis. After 

ensuring that the 

data are valid, 

NAHMS veterinary 

epidemiologists and 

statisticians analyze 

them, beginning 

with simple meth-

ods (such as percentages and averages) that sum-

marize the findings. Subsequently, more detailed 

statistical methods are used to examine the data, 

often to look for relationships among management 

practices and disease occurrence. Analyses adjust 

for statistical complexities associated with study 

design and for operations that do not participate in 

certain aspects of the study. 

5. Report preparation and distribution. NAHMS 

statisticians, commodity specialists, and epide-

miologists work together to generate summaries 

that reflect the national and regional popula-

tions of animals or operations and interpret the 

results. Primary products from the study include 

descriptive reports and concise information 

sheets. Descriptive reports contain tables, graphs, 

and some textual interpretation of study results. 

Information sheets briefly address very specific 

topics, such as vaccination or biosecurity practices. 

These products undergo extensive review by 

subject-matter specialists before they are released. 

National 

Animal Health 

Monitoring 

System

National Studies 

of U.S. Livestock 

and Poultry

United States Department of Agriculture

Animal and Plant Health Inspection Service

For More Information...

To access reports from previous NAHMS national 

studies or information on upcoming studies, visit the 

NAHMS Web site at http://nahms.aphis.usda.gov.

For further details, contact:

USDA-APHIS

Veterinary Services, Attention: NAHMS

NRRC Building B, Mailstop 2E7

2150 Centre Avenue

Fort Collins, CO 80526-8117

Phone: (970) 494-7000

E-mail: NAHMS@aphis.usda.gov 

Hallmarks of a NAHMS 

National Study • National in scope • Collaborative • Voluntary • Confidential • Scientifically based and 

statistically valid

Photo Credits: Cover photo by USDA, Jeff Vanuga. Inside image collage 

includes only USDA photos, except for the chick photo, which is the 

property of the University of Arizona, and the pig photo provided courtesy 

the National Pork Board.

USDA, R. Anson Eaglin

USDA, R. Anson Eaglin

Bovine Veterinarian Magazine, Geni Wren