United States

Department of

Agriculture

Animal and

Plant Health

Inspection

Service

Veterinary

Services

National

Animal Health

Monitoring

System

October 2007

Swine 2006

Part I: Reference of Swine Health and

Management Practices in the United

States, 2006
Mention of companies or commercial products does

not imply recommendation or endorsement by the

USDA over others not mentioned. USDA neither

guarantees nor warrants the standard of any product

mentioned. Product names are mentioned solely to

report factually on available data and to provide

specific information.

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.usda.aphis.gov

#N475.1007

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,

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equal opportunity provider and employer.

Cover photo courtesy of National Pork Board
USDA APHIS VS / i

Acknowledgments

This report was a cooperative effort between two U.S. Department of Agriculture

(USDA) Agencies: the National Agricultural Statistics Service (NASS) and the

Animal and Plant Health Inspection Service (APHIS).

Thanks to the NASS enumerators who contacted swine producers and collected

the data. Their hard work and dedication were invaluable. Thanks also to the

personnel at the USDA–APHIS–Veterinary Services’ Centers for Epidemiology

and Animal Health for their efforts in generating and distributing this report.

All participants are to be commended, particularly the producers whose voluntary

efforts made this report possible.

Larry M. Granger

Director

Centers for Epidemiology and Animal Health
ii / Swine 2006

Suggested bibliographic citation for this report:

USDA. 2007. Swine 2006, Part I: Reference of Swine Health and Management

Practices in the United States, 2006

USDA:APHIS:VS, CEAH. Fort Collins, CO

#N475.1007

Contacts for further information:

Questions or comments on data analysis: Dr. Charles Haley (970)-494-7000

Information on reprints or other reports: Ms. Kathy Snover (970) 494-7000

E-mail: NAHMS@aphis.usda.gov
USDA APHIS VS / iii

Table of Contents

Introduction 1

Terms Used in This Report 2

Section I: Population Estimates 5

A. Sow and Gilt Management 5

1. Production phases 5

2. Mating techniques 6

3. Culling and death loss 12

4. Introduction of breeding animals 14

B. Farrowing and Weaning Productivity 20

1. Farrowing productivity and death loss 20

2. Weaning 22

C. Nursery Productivity 25

1. Production phase 25

2. Nursery death loss 25

3. Age entering and leaving the nursery 27

D. Grower/Finisher Productivity 29

1. Production phase 29

2. Grower/finisher death loss 29

3. Days to market 31

E. Facility Management—All Phases 34

1. Production phases 34

2. Facility type 36

3. Pig flow 41

4. Multiple-site production 44

5. Source of sows and gilts 46

6. Source of nursery pigs 50

7. Source of grower/finisher pigs 54

F. Disease Prevention and Vaccination—All Phases 58

1. Disease prevention 58

2. Vaccination 60

3. Use of a veterinarian 62

G. Biosecurity 66

1. Restrictions for entry 66

2. Trucking 68

3. Proximity to other swine sites 70

4. Rodent control 71

5. Feral swine 71
iv / Swine 2006

H. General Management 73

1. Carcass disposal 73

2. Records 75

3. Marketing and shipments 76

Section II: Methodology 80

A. Needs Assessment 80

1. Number of respondents, by respondent type 80

B. Sampling and Estimation 81

1. State selection 81

2. Operation selection 81

3. Population inferences 81

C. Data Collection 82

1. General Swine Farm Report, July 17–September 15, 2006 82

D. Data Analysis 82

1. Validation and estimation 82

E. Sample Evaluation 82

1. General Swine Farm Report 82

Appendix I: Sample Profile 84

A. Responding Sites 84

1a. Total inventory 84

1b. Sow inventory 84

2. Type of site 84

3. Regions 85

4. Production phase 85

Appendix II: U.S. Swine Population and Operations 86

Number of Pigs on June 1, 2006, and Number of Operations in 2006 86

Appendix III: Swine 2006 Study Objectives and Related Outputs 87
Introduction

USDA APHIS VS / 1

Introduction

In 1983, promoters of the concept that would become the USDA’s National Animal

Health Monitoring System (NAHMS) envisioned a program that would monitor

changes and trends in national animal health and management, thereby providing

periodic snapshots of the U.S. food-animal industries. With these industry

overviews, members could identify opportunities for improvement, provide changing

foundations for research and special studies, and detect emerging problems.

NAHMS first national study of the swine industry, the 1990 National Swine Survey,

provided a snapshot of animal health and management that would serve as a

baseline from which to measure industry changes in animal health and

management. NAHMS conducted the 1990 National Swine Survey in 18 States,

with a target population of operations with at least one sow. The sample

represented 95 percent of the U.S. swine population. National estimates

generated from this study are reported in Morbidity/Mortality and Health

Management of Swine in the United States (November 1991).

NAHMS second national swine study, Swine ’95, was conducted in the top 16

swine States, which represented 91 percent of the U.S. swine population. The

target population for the first phase of Swine ‘95 was producers with at least one

pig. National estimates generated from this study are reported in Swine ’95 Part I:

Reference of 1995 Swine Management Practices (October 1995). The second

phase of Swine ’95 was conducted on sites with at least 300 market pigs.

National estimates generated from this study are reported in Part II: Reference of

1995 Grower/Finisher Health and Management Practices (May 1996).

Swine 2000, NAHMS third national swine study, was designed to provide both

participants and the industry with information on the U.S. swine herd on

operations with 100 or more pigs. The National Agricultural Statistics Service

(NASS) collaborated with Veterinary Services to select a producer sample

statistically designed to provide inferences to the Nation’s swine populations on

operations with 100 or more pigs. Included in the study were 17 of the major porkproducing States, which accounted for 94 percent of the U.S. pig inventory and 92

percent of U.S. pork producers with 100 or more pigs. Results from this study are

reported in Part I: Reference of Swine Health and Management in the United

States, 2000 (August 2001); Part II: Reference of Swine Health and Management

in the United States, 2000 (March 2002); Part III: Reference of Swine Health and

Environmental Management in the United States, 2000 (September 2002); and

Part IV: Changes in the U.S. Pork Industry, 1990-2000 (April 2005).

The Swine 2006 study is NAHMS’ fourth national study of the U.S. swine industry.

Seventeen States participated in the Swine 2006 study (see map). These States

accounted for 94 percent of swine operations and inventory on operations with 100
Introduction

2 / Swine 2006

or more pigs. A random sample of 5,000 swine producers was selected to be

visited by representatives from NASS between July 17 and September 15, 2006.

An on-site questionnaire was administered by NASS enumerators during this visit.

Producers that chose to continue in the study were visited twice by veterinary

medical officers (VMOs) who administered questionnaires and took biological/

environmental samples. VMOs made their initial visits between September 5,

2006, and March 15, 2007, and follow-up visits between December 4, 2006, and

March 15, 2007. Results from the first data collection period of this study are

presented in this report—Swine 2006 Part I: Reference of Swine Health and

Management Practices in the United States, 2006.

All NAHMS swine study reports are accessible online at http://

nahms.aphis.usda.gov.

All in, all out: A management approach in which the animals are moved as a

whole group, allowing a facility to be completely empty for a time. Usually, all-in,

all-out management also includes completely cleaning and disinfecting the facility

before refilling it with animals. All-in, all-out management can be done at any level:

pen area, room, building, or entire facility.

Average: For site average—a single value for each operation summed over all

operations reporting divided by the number of operations reporting (see average

number of days quarantine p 16). For a pig-level average —a single operation

value multiplied by the number of animals on that operation; then values are

summed across operations and divided by total number of animals on all

operations (see average age at weaning p. 22).

Swine 2006 Participating States

Regions

North

West Central

East Central

South

Terms Used in

This Report
Introduction

USDA APHIS VS / 3

Hand-mating: Term used when females are selected individually to be bred with a

specific boar. Both sow and boar are placed in the same pen, and a stockperson

might have to help with the physical aspects of mating.

Operation: The overall business and top-level management unit for a swinerearing facility, which might consist of one or more sites. An operation can

encompass all production phases of swine rearing (i.e., gestation, farrowing,

nursery, and grower/finisher) on one or more sites (geographic locations), each

devoted to a different production phase or combination of phases (see also “Site”).

Percent animals: The number of animals on sites with a certain attribute divided

by the total number of animals on all sites. In some cases, it is assumed that the

attribute applies to all animals on the site. The animal type is defined in each table

and may include total inventory, sow inventory, number of pigs that entered the

nursery, or other specific pig groups. The “percent animals” estimates primarily

reflect the larger sites, which have the majority of pigs.

Percent sites: The number of sites with a certain attribute divided by the total

number of sites. Percentages will sum to 100 where the attributes are mutually

exclusive (i.e., percentage of sites located within each region). Percentages will

not sum to 100 where the attributes are not mutually exclusive (i.e., the

percentage of sites using treatment methods where sites may have used more

than one method). The “percent sites” estimates primarily reflect the smaller

producers, since they make up the majority of sites.

Population estimates: Estimates in this report are provided with a measure of

precision called the standard error. A 95-percent confidence interval can be

approximated with bounds equal to the estimate, plus or minus two standard

errors. If the only error is sampling error, the confidence intervals created in this

manner will contain the true population mean 95 out of 100 times. In the example

to the left, an estimate of 7.5 with a standard error of 1.0 results in limits of 5.5 to

9.5 (two times the standard error above and below the estimate). The second

estimate of 3.4 shows a standard error of 0.3 and results in limits of 2.8 and 4.0.

Alternatively, the 90-percent confidence interval would be created by multiplying

the standard error by 1.65 instead of 2. Most estimates in this report are rounded

to the nearest tenth. If rounded to 0, the standard error was reported (0.0). If there

were no reports of the event, no standard error was reported (—).

Standard Errors

(1.0)

10

9

8

7

6

5

4

3

2

1

0 (0.3)

Examples of a 95% Confidence Interval

95% Confidence

Intervals
Introduction

4 / Swine 2006

Pen-mating: One or more boars are introduced to a group of females for natural

breeding.

Regions:

North: Michigan, Minnesota, Pennsylvania, and Wisconsin

West Central: Colorado, Kansas, Missouri, Nebraska, South Dakota

East Central: Illinois, Indiana, Iowa, and Ohio

South: Arkansas, North Carolina, Oklahoma, and Texas

Sample profile: Information that describes characteristics of the operations from

which Swine 2006 data were collected.

Separate site: This term can mean that a facility is at a completely separate

geographic location or in the same location but physically separated (no livestock

runways or paths joining to other production facilities). It also might be managed

as its own site, with separate procedures, biosecurity measures, and workers.

Size of site: Size groupings were based on total number of swine present on June

1, 2006. Size of site was categorized as small (fewer than 2,000), medium,

(2,000-4,999), and large (5,000 or more). For tables relating to sow and gilt

management as well as farrowing and weaning productivity, size of site was based

on the number of sows and gilts on-site: small (fewer than 250), medium (250 to

499), and large (500 or more).

Site: One geographic location or address that functions as a unit to produce one

or more production phases in swine rearing. Examples would be a gestation/

farrowing site or a nursery site. A site can encompass more than one production

phase, such as a “farrow to finish” site, which has gestation, farrowing, nursery,

and grower/finisher hogs all at one location. A site can be a part of an operation or

it can be the whole operation, if the operation has only one site. (See also

“Operation.”)

Total Inventory: All swine present on the site on June 1, 2006.
Section I: Population Estimates

USDA APHIS VS / 5

1. Production phases

A pregnant sow or gilt not yet ready to give birth is considered to be in the

gestation phase. The farrowing phase refers to the short time before a sow or gilt

gives birth, the birthing process (farrowing), and subsequent time when the

newborn piglets are nursing. Nearly 40 percent of sites had gestation and

farrowing production phases. A smaller percentage of medium sites had these

production phases than their small and large counterparts.

a. Percentage of sites by production phase and by size of site:

Section I: Population Estimates

A. Sow and Gilt

Management

Percent Sites 

Size of Site (Total Inventory) 

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Production 

Phase Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Gestation 47.3 (1.7) 19.0 (1.8) 32.4 (2.9) 39.8 (1.2) 

Farrowing 46.1 (1.7) 18.9 (1.8) 32.2 (2.9) 39.0 (1.2) 

A higher percentage of sites in the West Central region had gestation and

farrowing production phases (48.8 and 47.4 percent of sites, respectively)

compared to sites in the East Central and South regions.

b. Percentage of sites by production phase and by region:

Percent Sites 

Region 

North West Central East Central South 

Production 

Phase Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Gestation 39.3 (2.6) 48.8 (2.8) 38.0 (1.9) 33.9 (2.7) 

Farrowing 37.7 (2.7) 47.4 (2.8) 37.6 (1.9) 33.7 (2.7) 
Section I: Population Estimates

6 / Swine 2006

2. Mating techniques A service consists of one or more matings done in the same heat/estrus period. A

mating may be by artificial insemination or involve contact with a boar (e.g., penmating). Nearly 80 percent of sows on all sites were mated two or more times per

service. Small sites had a substantially higher percentage of pen-mating (62.5

percent of sows) than medium and large sites (23.4 and 1.9 percent of sows,

respectively).

a. Percentage of sows serviced from March through May 2006, by number of

matings per service and by size of site:

Percent Sows 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Number 

Matings Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Pen-mating 

only 62.5 (4.0) 23.4 (5.0) 1.9 (0.6) 9.3 (1.1) 

1 6.6 (1.4) 7.0 (1.7) 12.4 (3.4) 11.5 (2.9) 

2 26.7 (3.8) 61.0 (5.2) 63.8 (4.8) 59.9 (4.1) 

3 or more 4.2 (1.6) 8.6 (2.7) 21.9 (4.0) 19.3 (3.3) 

Total 100.0 100.0 100.0 100.0 
USDA APHIS VS / 7

 Section I: Population Estimates

Note: the following table excludes sites that only used pen-mating. Artificial

insemination was the predominant method of mating sows during first, second,

and third or more matings (91.6, 90.0, and 51.0 percent of sows, respectively).

Individual hand-mating with a boar or pen-mating with multiple females appear to

be used on few sows during any mating.

b. For sites that did not use pen-mating exclusively, percentage of sows serviced,

by predominant mating technique used for first, second, and third or more

matings:

Percent Sows 

First 

Mating 

Second 

Mating 

Third or 

More Mating 

Mating Technique Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Artificial insemination 91.6 (5.1) 90.0 (5.1) 51.0 (5.8) 

Individual hand-mating 

naturally 2.4 (0.5) 7.5 (5.2) 0.2 (0.1) 

Pen-mating with 

multiple females and 

one or more boars 6.0 (5.2) 1.2 (0.5) 1.5 (1.0) 

No second mating N/A 1.3 (0.5) N/A 

No third mating N/A N/A 47.3 (5.8) 

Total 100.0 100.0 100.0 
Section I: Population Estimates

8 / Swine 2006

For sites that used a second mating for sows, the majority (76.1 percent) used

artificial insemination during both matings, which accounted for the majority of

sows serviced two or more times (89.8 percent). However, the remaining 10.2

percent of sows were bred using either hand-mating or pen-mating during any

mating.

c. For sites that used a second mating for sows, percentage of sites and

percentage of sows serviced, by predominant mating technique used for first and

second matings:

Mating Technique Percent Sites Percent Sows 

1st Mating 2nd Mating Percent Std. Error Percent Std. Error 

Artificial 

insemination 

Artificial 

insemination 76.1 (3.0) 89.8 (5.1) 

Artificial 

insemination 

Handmating 2.5 (1.2) 0.7 (0.3) 

Artificial 

insemination Pen-mating 3.6 (1.1) 1.1 (0.4) 

Hand-mating Artificial 

insemination 2.1 (0.7) 0.8 (0.3) 

Hand-mating Handmating 11.2 (2.2) 1.3 (0.3) 

Hand-mating Pen-mating 1.1 (0.9) 0.2 (0.2) 

Pen-mating Any other 

technique 3.4 (1.7) 6.1 (5.3) 

Total 100.0 100.0 
USDA APHIS VS / 9

 Section I: Population Estimates

A higher percentage of large and medium sites sites used artificial insemination as

a predominant technique of mating sows than did small sites.

d. Percentage of sites that used artificial insemination as a predominant mating

technique for sows during at least one mating, by size of site:

Nearly three of four gilts (70.7 percent) were mated two or more times per service.

e. Percentage of gilts serviced from March through May 2006, by number of

matings per service and by size of site:

Percent Sites 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

20.8 (2.3) 65.7 (5.9) 91.6 (2.4) 40.1 (2.1) 

Percent Gilts 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Number 

Matings Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Pen-mating 

only 75.4 (3.7) 43.1 (10.8) 4.2 (1.2) 14.8 (2.1) 

1 6.3 (1.6) 7.3 (2.2) 16.1 (5.4) 14.5 (4.6) 

2 14.5 (2.6) 43.4 (9.0) 64.5 (5.8) 57.3 (4.8) 

3 or more 3.8 (2.2) 6.2 (2.8) 15.2 (4.0) 13.4 (3.4) 

Total 100.0 100.0 100.0 100.0 
Section I: Population Estimates

10 / Swine 2006

As with sows, artificial insemination was the predominant method used for gilts

during first, second, and third or more matings.

f. For sites that did not use pen-mating exclusively, percentage of gilts serviced,

by predominant mating technique used for first, second, and third or more

matings:

Percent Gilts 

First 

Mating 

Second 

Mating 

Third or 

More Mating 

Mating Technique Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Artificial insemination 92.8 (2.9) 90.2 (3.2) 47.1 (6.5) 

Individual 

hand-mating naturally 4.1 (0.8) 6.1 (2.9) 0.6 (0.3) 

Pen-mating with multiple 

females and one or 

more boars 3.1 (2.8) 0.9 (0.4) 2.9 (1.8) 

No second mating N/A 2.8 (1.3) N/A 

No third mating N/A N/A 49.4 (6.3) 

Total 100.0 100.0 100.0 
USDA APHIS VS / 11

 Section I: Population Estimates

As was the case with sows, the majority of sites that used a second mating for

gilts used artificial insemination during both matings (71.9 percent of sites), which

accounted for the majority of gilts serviced two or more times (91.2 percent).

g. For sites that used a second mating for gilts, percentage of sites and

percentage of gilts serviced, by predominant mating technique used during first

and second matings:

Mating Technique Percent Sites Percent Gilts 

1st Mating 2nd Mating Percent Std. Error Percent Std. Error 

Artificial 

insemination 

Artificial 

insemination 71.9 (3.4) 91.2 (3.1) 

Artificial 

insemination 

Handmating 1.2 (0.6) 1.0 (0.6) 

Artificial 

insemination Pen-mating 2.0 (0.8) 0.5 (0.3) 

Hand-mating Artificial 

insemination 4.2 (1.2) 1.4 (0.5) 

Hand-mating Handmating 15.7 (2.8) 2.4 (0.6) 

Hand-mating Pen-mating 1.5 (1.2) 0.3 (0.3) 

Pen-mating Any other 

technique 3.5 (1.8) 3.2 (2.9) 

Total 100.0 100.0 

A higher percentage of large and medium sites used artificial insemination as a

predominant method of mating gilts than did small sites.

h. Percentage of sites that used artificial insemination as a predominant mating

technique for gilts during at least one mating, by size of site:

Percent Sites 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

17.6 (2.6) 57.9 (6.8) 89.1 (2.8) 41.8 (2.5) 
Section I: Population Estimates

12 / Swine 2006

Nearly four of five sites (79.0 percent) purchased semen for artificial insemination.

Purchasing semen eliminates the need to keep boars on-site.

i. Of those sites using artificial insemination, percentage of sites by source of

semen:

Semen Source Percent Sites Std. Error 

Purchased 79.0 (2.5) 

Collected and processed on-site 16.8 (2.2) 

Collected and processed off-site, but 

not purchased 15.9 (2.6) 

3. Culling and death loss

The number of breeding-age females that died or were culled from December 2005

through May 2006 was calculated as a percentage of the June 1, 2006, sow and

gilt inventory in the breeding herd. A higher percentage of breeding-age females

(21.1 percent) were culled on large sites compared to medium and small sites

(12.7 and 12.4 percent, respectively). Overall, 19.5 percent were culled and 4.3

percent died.

a. Breeding-age females that died or were culled from December 2005 through

May 2006 as a percentage of June 1, 2006, sow and gilt inventory,* by size of site:

Percent Breeding-Age Females 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Reason 

Removed Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Died 2.9 (0.3) 2.5 (0.3) 4.7 (0.3) 4.3 (0.3) 

Culled 12.4 (0.8) 12.7 (1.2) 21.1 (1.0) 19.5 (0.9) 

*Sows and bred gilts for breeding plus unmated gilts in the breeding herd. 
USDA APHIS VS / 13

 Section I: Population Estimates

Age and reproductive failure were the two most common reasons breeding-age

females were culled (36.6 and 26.3 percent, respectively). Age, reproductive

failure, and performance accounted for over three-fourths (75.9 percent) of all

culled females.

b. Percentage of culled breeding-age females from December 2005 through May

2006, by reason culled:

Reason Culled Percent Culled Females Standard Error 

Old age 36.6 (2.6) 

Lameness 15.2 (2.3) 

Performance* 13.0 (1.1) 

Reproductive failure 26.3 (1.9) 

Injury 4.0 (0.6) 

Other reason 4.9 (0.8) 

Total 100.0 

*Small litter size, high preweaning mortality, or low birth weight. 

0

10

20

30

40

36.6

15.2

13.0

26.3

4.0 4.9

Old age Lameness Performance* Reproductive

failure

Injury Other

reason

Reason Culled

Percent

Percentage of Culled Breeding-Age Females From December 2005 Through

May 2006, by Reason Culled

*Small litter size, high preweaning mortality, or low birth weight.
Section I: Population Estimates

14 / Swine 2006

4. Introduction of breeding animals

New gilts, and in some cases new sows, may require initial isolation before

entering the breeding herd to prevent the introduction of new pathogens. Initial

isolation is one method used by producers to prevent disease transmission when

animals come from another site or a different health management system. The

percentage of sites that always isolated new breeding females ranged from 61.1

percent of large sites to 26.5 percent of small sites. However, a higher percentage

of small sites (51.0 percent) typically had no new arrivals compared to large sites

(21.4 percent).

a. Percentage of sites by frequency new breeding females were typically isolated

or quarantined, and by size of site:

Percent Sites 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Frequency Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Always 26.5 (2.4) 37.4 (5.9) 61.1 (3.8) 34.3 (2.0) 

Sometimes 5.5 (1.2) 6.4 (3.5) 2.5 (1.1) 5.0 (0.9) 

Never 17.0 (2.1) 21.9 (5.4) 15.0 (2.7) 17.0 (1.6) 

No new 

arrivals 51.0 (2.8) 34.3 (6.0) 21.4 (3.0) 43.7 (2.2) 

Total 100.0 100.0 100.0 100.0 
USDA APHIS VS / 15

 Section I: Population Estimates

0

10

20

30

40

50

60

70

No new arrivals

Never

Sometimes

Always

Frequency

Percent

Small (Fewer than 250) Medium (250-499) Large (500 or more) All Sites

Size of Site (Sow and Gilt Inventory)

Percentage of Sites by Frequency New Breeding Females were Typically

Isolated or Quarantined, and by Size of Site

26.5

5.5

17.0

51.0

37.4

6.4

21.9

34.3

61.1

2.5

15.0

21.4

34.3

5.0

17.0

43.7
Section I: Population Estimates

16 / Swine 2006

New breeding males may carry a variety of pathogens which may affect the

reproductive success of a breeding herd. The percentages of sites that always

isolated new breeding males did not differ substantially by size of site. However, a

higher percentage of large sites (32.3 percent) closed their herds to new breeding

males compared to small sites (16.7 percent).

b. Percentage of sites by frequency new breeding males were typically isolated or

quarantined, and by size of site:

Percent Sites 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Frequency Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Always 49.5 (2.8) 43.9 (6.2) 47.7 (4.1) 48.6 (2.2) 

Sometimes 12.3 (1.8) 2.5 (2.0) 5.5 (2.5) 10.1 (1.4) 

Never 21.5 (2.3) 22.7 (5.6) 14.5 (2.5) 20.2 (1.8) 

No new 

arrivals 16.7 (2.0) 30.9 (5.6) 32.3 (3.6) 21.1 (1.7) 

Total 100.0 100.0 100.0 100.0 

On average, for sites that isolated new breeding females or males, large sites

isolated both breeding females and breeding males for more days than small

sites. There were no substantial differences by gender within each size category

in the average number of days animals were isolated.

c. For sites that isolated or quarantined new arrivals, site average number of days

new arrivals were isolated or quarantined, by gender and by size of site:

Site Average Number of Days 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Gender Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

Breeding 

females 30.3 (1.5) 36.1 (3.0) 49.7 (1.9) 37.0 (1.3) 

Breeding 

males 28.3 (1.1) 41.1 (3.5) 47.1 (2.4) 32.6 (1.1) 
USDA APHIS VS / 17

 Section I: Population Estimates

For large sites, 35.1 percent tested at least some new breeding females for

disease exposure, while 5 of 10 (50.3 percent) tested all new breeding females.

For medium sites, 8.3 percent tested at least some new breeding females for

disease exposure, while 29.4 percent tested all new breeding females. For small

sites, 15.3 percent tested at least some new breeding females, while 34.9 percent

tested all new breeding females. Similar patterns were seen for breeding males.

d. For sites with newly arriving breeding females, percentage of sites that typically

tested new breeding females for disease exposure before introduction to the

breeding herd, by proportion of animals tested and by size of site:

Photo courtesy of National Pork Board

Percent Sites 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Proportion Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

All 34.9 (3.6) 29.4 (6.0) 50.3 (4.7) 38.6 (2.7) 

Some 15.3 (2.8) 8.3 (3.1) 35.1 (4.6) 20.1 (2.3) 

None 49.8 (3.8) 62.3 (6.7) 14.6 (2.7) 41.3 (2.8) 

Total 100.0 100.0 100.0 100.0 
Section I: Population Estimates

18 / Swine 2006

e. For sites with newly arriving breeding males, percentage of sites that typically

tested new breeding males for disease exposure before introduction to the

breeding herd, by proportion of animals tested and by size of site:

0

10

20

30

40

50

60

70

None

Some

All

Proportion

Small (Fewer than 250) Medium (250-499) Large (500 or more) All Sites

Size of Site (Sow and Gilt Inventory)

Percent

For Sites with Newly Arriving Breeding Females, Percentage of Sites that

Typically Tested New Breeding Females for Disease Exposure Before

Introduction to the Breeding Herd, by Proportion of Animals Tested and

by Size of Site

34.9

15.3

49.8

29.4

8.3

62.3

50.3

35.1

14.6

38.6

20.1

41.3

Percent Sites 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Proportion Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

All 37.4 (2.9) 38.2 (7.6) 58.2 (5.2) 41.0 (2.4) 

Some 12.9 (2.1) 2.7 (1.4) 21.5 (4.8) 13.6 (1.8) 

None 49.7 (3.0) 59.1 (7.6) 20.3 (4.0) 45.4 (2.5) 

Total 100.0 100.0 100.0 100.0 
USDA APHIS VS / 19

 Section I: Population Estimates

Approximately 9 of 10 large sites (90.5 percent), 7 of 10 medium sites (74.8

percent), and 6 of 10 small sites (59.7 percent) administered vaccinations as a

way of acclimating new arrivals to on-site pathogens. Vaccines used may not

exactly match specific strains of disease present on-site but may enhance the

animals’ general immunity to them. Many sites relied on some sort of exposure of

new breeding stock to pigs present as a way of acclimating new arrivals.

f. For sites with newly arriving breeding stock, percentage of sites by method used

to acclimate new arrivals and by size of site:

Percent Sites 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Method Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Feedback of 

feces from 

other swine 12.6 (2.0) 34.1 (6.8) 44.7 (4.6) 20.8 (1.9) 

Feedback of 

mummies, 

placentas, or 

stillborn pigs 4.6 (1.2) 10.9 (3.9) 23.0 (4.5) 8.8 (1.4) 

Exposure to 

cull females 

(gilts and 

sows) 29.0 (2.6) 59.6 (6.8) 50.9 (4.5) 35.8 (2.2) 

Exposure to 

sick pigs 4.5 (1.3) 9.6 (4.4) 9.9 (3.3) 6.0 (1.2) 

Give 

vaccinations 59.7 (3.0) 74.8 (6.7) 90.5 (2.2) 67.1 (2.3) 

Other 6.8 (1.6) 2.9 (1.4) 2.0 (1.0) 5.5 (1.2) 
Section I: Population Estimates

20 / Swine 2006

B. Farrowing and

Weaning Productivity

1. Farrowing productivity and death loss

The total number of piglets born or born alive per litter is a measure of reproductive

performance. Overall, 11.5 piglets were born per litter, of which 10.5 were born

alive and 9.4 were weaned.

a. Average per litter productivity from December 2005 through May 2006:

On average, large and medium sites had approximately one more piglet born alive

per litter than small sites. Large sites also averaged about one more weaned piglet

per litter than small sites.

Average Per Litter Productivity 

Measure (Per Litter) Number Std. Error Percent Std. Error 

Stillbirths and 

mummies 1.0 (0.0) 8.4 (0.3) 

Born alive 10.5 (0.1) 91.6 (0.3) 

Total born 11.5 (0.1) 100.0 

Preweaning deaths 1.1 (0.0) 10.9 (0.4) 

Weaned 9.4 (0.1) 89.1 (0.4) 

Total born alive 10.5 (0.1) 100.0 
USDA APHIS VS / 21

 Section I: Population Estimates

b. Average per litter productivity from December 2005 through May 2006, by size

of site:

Crushing by sow accounted for over half of preweaning deaths (54.5 percent) from

December 2005 through May 2006. Disease-related problems such as scours and

respiratory problems led to 14.0 percent of preweaning deaths. Low viability was

the most common other identified problem.

c. Percentage of preweaning deaths from December 2005 through May 2006,

by producer-identified cause:

Average Per Litter Productivity 

Size of Site (Sow and Gilt Inventory) 

Small (Fewer than 250) Medium (250-499) Large (500 or More)

Measure 

(Per Litter) No. 

Std. 

Err. Pct. 

Std. 

Err. No. 

Std. 

Err. Pct. 

Std. 

Err. No. 

Std. 

Err. Pct. 

Std. 

Err. 

Stillbirths and 

mummies 0.9 (0.1) 9.2 (0.8) 0.9 (0.0) 7.9 (0.4) 1.0 (0.0) 8.4 (0.3) 

Born alive 9.3 (0.1) 90.8 (0.8) 10.2 (0.1) 92.1 (0.4) 10.7 (0.1) 91.6 (0.3) 

Total born 10.2 (0.1) 100.0 11.1 (0.1) 100.0 11.7 (0.1) 100.0 

Preweaning 

deaths 0.8 (0.0) 8.5 (0.4) 1.0 (0.1) 9.8 (0.6) 1.2 (0.1) 11.3 (0.5) 

Weaned 8.5 (0.1) 91.5 (0.4) 9.2 (0.1) 90.2 (0.6) 9.5 (0.1) 88.7 (0.5) 

Total 

born alive 9.3 (0.1) 100.0 10.2 (0.1) 100.0 10.7 (0.1) 100.0 

Producer-Identified Cause 

Percent Preweaning 

Deaths 

Standard 

 Error 

Scours 9.3 (1.1) 

Crushing by sow (laid on) 54.5 (1.9) 

Starvation 13.8 (1.2) 

Respiratory problems 4.7 (1.3) 

Other identified problems 9.9 (1.7) 

Unknown problems 7.8 (1.1) 

Total 100.0 
Section I: Population Estimates

22 / Swine 2006

2. Weaning

The average piglet-weaning age of 19.4 days was influenced by medium and large

sites, which tend to wean piglets earlier (16-20 days) than small sites and account

for a relatively large number of pigs.

a. Average age of piglets at weaning from December 2006 through May 2006:

Average Age (Days) Standard Error 

19.4 (0.2) 

0

20

40

60

9.3

54.5

13.8

4.7

9.9

7.8

Scours Crushing

by sow

Starvation Respiratory

problems

Other identified

problems

Unknown

problems

Producer-Identified Cause

Percent

Percentage of Preweaning Deaths From December 2005 Through May 2006,

by Producer-Identified Cause
USDA APHIS VS / 23

 Section I: Population Estimates

Over 9 of 10 large sites (93.2 percent) and nearly 9 of 10 medium sites (86.7

percent) weaned piglets at 16 to 27 days of age, compared to 4 of 10 small sites

(40.5 percent). More than half of small sites (57.6 percent) weaned at 28 or more

days, compared to 12.0 and 0.7 percent of medium and large sites, respectively.

b. Percentage of sites by age piglets were weaned and by size of site:

Percent Sites 

Size of Site (Sow and Gilt Inventory)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Weaning Age 

(Days) Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Less than 16 1.9 (0.8) 1.3 (0.8) 6.1 (1.7) 2.7 (0.7) 

16 to 20 7.9 (1.4) 50.5 (6.2) 71.1 (3.8) 24.1 (1.7) 

21 to 27 32.6 (2.6) 36.2 (6.0) 22.1 (3.6) 30.8 (2.1) 

28 to 34 23.6 (2.4) 5.5 (2.8) 0.7 (0.6) 17.5 (1.8) 

35 or more 34.0 (2.6) 6.5 (3.6) 0.0 (--) 24.9 (2.0) 

Total 100.0 100.0 100.0 100.0 
Section I: Population Estimates

24 / Swine 2006

0 20 40 60 80

35 or more

28 to 34

21 to 27

16 to 20

Less than 16

Weaning Age (Days)

1.9

7.9

32.6

23.6

34.0

1.3

50.5

36.2

5.5

6.5

6.1

71.1

22.1

0.7

0.0

2.7

24.1

30.8

17.5

24.9

Percent

Fewer

than 250

250-499

500 or

more

All Sites

Size of Site

(Sow and Gilt

Inventory)

Percentage of Sites by Age Piglets were Weaned and by Size of Site

Nearly 7 of 10 weaned pigs were on sites that weaned at 16 to 20 days.

c. Percentage of weaned pigs* on operations that weaned pigs at the following

ages:

Weaning Age (Days) Percent Pigs Std. Error 

Less than 16 6.3 (2.6) 

16 to 20 69.4 (4.1) 

21 to 27 20.1 (3.6) 

28 to 34 2.2 (0.4) 

35 or more 2.0 (0.3) 

Total 100.0 

*As a percentage of pigs weaned from December 2005 through May 2006. 
USDA APHIS VS / 25

 Section I: Population Estimates

C. Nursery Productivity 1. Production phase

About half of all sites (53.3 percent) had a nursery phase. Approximately one-third

of sites in the South region (33.5 percent) had a nursery phase, the lowest

percentage of any region. The relatively low percentage in the South region may

reflect the infrastructure that has developed in the other regions, which grow out

pigs transported from the South.

Percentage of sites with a nursery phase, by region:

Percent Sites 

Region 

North West Central East Central South All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

51.3 (2.7) 57.0 (3.0) 56.8 (1.9) 33.5 (2.9) 53.3 (1.3) 

2. Nursery death loss

There was no substantial difference in the percentages of nursery pig deaths

across the three size groups.

a. Percentage of nursery pigs that died in the nursery phase* from December 2005

through May 2006, by size of site:

Percent Nursery Pigs 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

3.3 (0.5) 2.9 (0.2) 2.9 (0.2) 2.9 (0.1) 

*As a percentage of pigs that entered the nursery phase 
Section I: Population Estimates

26 / Swine 2006

The percentages of deaths by producer-identified cause did not differ substantially

across the three size groups. Respiratory problems accounted for the highest

percentage of all nursery deaths (44.2 percent). Of the 4.1 percent of all nursery

deaths ascribed to other identified problems, nearly half were caused by injury or

trauma.

b. Percentage of nursery-phase deaths from December 2005 through May 2006,

by producer-identified cause and by size of site:

Percent Deaths 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000)

Medium 

(2,000-4,999)

Large 

(5,000 

or More) All Sites 

ProducerIdentified Cause Pct. Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Scours 12.7 (1.8) 12.9 (1.6) 12.2 (1.9) 12.5 (1.1) 

Starvation 10.2 (1.3) 10.6 (1.3) 9.3 (1.5) 9.8 (0.9) 

Respiratory 

problems 49.8 (6.8) 44.5 (2.6) 41.9 (2.8) 44.2 (2.3) 

CNS/meningitis 12.2 (2.7) 17.8 (1.8) 21.6 (3.1) 18.7 (1.9) 

Other identified 

problems 3.8 (1.1) 4.5 (1.3) 4.0 (1.4) 4.1 (0.8) 

Unknown 

problems 11.3 (2.1) 9.7 (1.1) 11.0 (1.9) 10.7 (1.1) 

Total 100.0 100.0 100.0 100.0 
USDA APHIS VS / 27

 Section I: Population Estimates

3. Age entering and leaving the nursery

The average age of pigs entering the nursery was younger for large and medium

sites compared to small sites, which relates to the earlier weaning age on large

and medium sites (table b, p 23).

a. Average age of pigs entering the nursery, by size of site:

Average Age (Days) 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

22.1 (0.4) 18.6 (0.2) 18.7 (0.2) 19.3 (0.1) 

0

20

40

60

12.5

9.8

44.2

18.7

4.1

10.7

Scours Starvation Respiratory

problems

CNS/

meningitis

Other identified

problems

Unknown

problems

Percent

Producer-Identified Cause

Percentage of Nursery-Phase Deaths From December 2005 Through May

2006, by Producer-Identified Cause
Section I: Population Estimates

28 / Swine 2006

There were no substantial differences across size groups in the average age that

pigs left the nursery.

b. Average age of pigs leaving the nursery, by size of site:

Average Age (Days) 

Size of Site (Total Inventory)

Small 

(Fewer than 

2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

65.7 (0.7) 65.6 (0.6) 64.2 (0.8) 64.8 (0.5) 

There was a small difference between small and medium sites in the average

number of days pigs spent in the nursery.

c. Average number of days pigs spent in the nursery, by size of site:

Average Days

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

43.6 (0.7) 47.0 (0.6) 45.5 (0.8) 45.5 (0.5) 
USDA APHIS VS / 29

 Section I: Population Estimates

D. Grower/Finisher

Productivity

1. Production phase

Eight of 10 sites had a grower/finisher phase. As was the case with the nursery

phase (table 1. p 25), the South region had the lowest percentage of sites with a

grower/finisher phase than any other region.

Percentage of sites with a grower/finisher phase, by region:

Percent Sites 

Region 

North West Central East Central South All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

85.5 (2.0) 79.8 (2.7) 82.7 (1.5) 55.2 (3.0) 80.0 (1.0) 

2. Grower/finisher death loss

As with nursery pig deaths, there were no substantial differences by size of site in

the percentages of deaths during the grower/finisher phase.

a. Percentage of grower/finisher pigs that died during the grower/finisher phase*

from December 2005 through May 2006, by size of site:

Percent Grower/Finisher Pigs 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

3.4 (0.2) 3.7 (0.2) 4.4 (0.4) 3.9 (0.2) 

*As a percentage of pigs that entered the grower/finisher phase. 
Section I: Population Estimates

30 / Swine 2006

For all producer-identified causes of grower/finisher deaths, the percentages of

grower/finisher deaths did not differ substantially by size of site. The majority of

grower/finisher deaths (61.1 percent) were due to respiratory problems. Most

producer-identified deaths attributed to other identified problems were caused by

gastrointestinal problems, such as hemorrhagic bowel syndrome or ileitis-related

diseases.

b. Percentage of grower/finisher pig deaths from December 2005 through May

2006, by producer-identified cause and by size of site:

Percent Deaths 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 

or More) All Sites 

ProducerIdentified 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Scours 7.4 (1.1) 6.3 (0.7) 6.7 (1.1) 6.7 (0.6) 

Lameness 5.8 (0.6) 4.9 (0.5) 5.5 (0.6) 5.4 (0.3) 

Injury/trauma 5.8 (0.6) 5.2 (0.6) 4.3 (0.7) 4.9 (0.4) 

Respiratory 

problems 59.4 (2.5) 64.3 (2.1) 59.8 (4.2) 61.1 (2.3) 

Stress 5.6 (0.7) 2.9 (0.3) 2.3 (0.4) 3.2 (0.3) 

Other 

identified 

problems 4.3 (0.7) 6.4 (1.0) 10.6 (6.7) 8.0 (3.4) 

Unknown 

problems 11.7 (1.1) 10.0 (1.0) 10.8 (1.9) 10.7 (1.0) 

Total 100.0 100.0 100.0 100.0 
USDA APHIS VS / 31

 Section I: Population Estimates

3. Days to market

The were no substantial differences across site sizes in the average age of pigs

entering the grower/finisher phase.

a. Average age of pigs entering the grower/finisher unit from December 2005

through May 2006, by size of site:

Average Age (Days) 

Size of Site (Total Inventory) 

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

66.1 (0.7) 64.2 (0.6) 65.1 (0.6) 65.1 (0.4) 

Unknown problems

Other identified problems

Stress

Respiratory problems

Injury/trauma

Lameness

Scours

Producer-Identified

Cause

6.7%

5.4%

4.9%

61.1%

3.2%

8.0%

10.7%

Percentage of Grower/Finisher Pig Deaths From December 2005 through

May 2006, by Producer-Identified Cause
Section I: Population Estimates

32 / Swine 2006

There was a slight difference in the average age of pigs leaving the grower/finisher

unit between large sites versus medium and small sites (184.3 days versus 175.5

and 176.3 days, respectively). This difference can be partially explained by the

high percentage of pigs (41.7 percent) that left at 181 or more days of age

(table c).

b. Average age of pigs leaving the grower/finisher unit, by size of site:

Average Age (Days) 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

176.3 (1.5) 175.5 (1.5) 184.3 (2.3) 179.7 (1.3) 

c. Percentage of sites, and percentage of grower/finisher pigs on these sites, by

age of pigs leaving the grower/finisher unit:

Age (Days) 

Percent 

Sites Std. Error 

Percent 

Pigs Std. Error 

Less than 160 16.6 (1.2) 15.5 (1.4) 

160 to 165 10.4 (0.9) 9.9 (1.1) 

166 to 180 38.9 (1.5) 32.9 (2.1) 

181 to 209 24.3 (1.3) 35.4 (2.7) 

210 or more 9.8 (1.0) 6.3 (1.0) 

Total 100.0 100.0 
USDA APHIS VS / 33

 Section I: Population Estimates

0

10

20

30

40

50

Pigs

Sites

16.6 15.5

10.4 9.9

38.9

32.9

24.3

35.4

9.8

6.3

Less than 160 160-165 166-180 181-209 210 or more

Age (Days)

Percent

Percentage of Sites, and Percentage of Grower/Finisher Pigs on These Sites,

by Age of Pigs Leaving the Grower/Finisher Unit
Section I: Population Estimates

34 / Swine 2006

Pigs on large sites had a significantly longer grower/finisher phase (119.2 days)

than pigs on medium and small sites (111.3 and 110.2 days, respectively).

d. Average number of days pigs spent in the grower/finisher phase, by size of site:

Average Number of Days

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

110.2 (1.3) 111.3 (1.4) 119.2 (2.2) 114.6 (1.2) 

E. Facility Management

—All Phases

1. Production phases

Compared to the other regions, the South region had the lowest percentage of

sites with nursery and grower/finisher phases (33.5 and 55.2 percent of sites,

respectively).

a. Percentage of sites by production phase and by region:

 Percent Sites 

 Region 

North 

West 

Central 

East 

Central South All Sites 

Production Phase Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Gestation 39.3 (2.6) 48.8 (2.8) 38.0 (1.9) 33.9 (2.7) 39.8 (1.2) 

Farrowing 37.7 (2.7) 47.4 (2.8) 37.6 (1.9) 33.7 (2.7) 39.0 (1.2) 

Nursery 51.3 (2.7) 57.0 (3.0) 56.8 (1.9) 33.5 (2.9) 53.3 (1.3) 

Grower/finisher 85.5 (2.0) 79.8 (2.7) 82.7 (1.5) 55.2 (3.0) 80.0 (1.0) 
USDA APHIS VS / 35

 Section I: Population Estimates

Slightly more than one-quarter of all sites (26.4 percent) had all four production

phases (gestation, farrowing, nursery, and grower/finisher). When sites in each

region were broken out by combinations of production phases, only 8.0 percent of

sites in the South region had all four phases on one site. However, compared to

sites in the other three regions, a substantially higher percentage of sites in the

South region (20.6 percent) specialized in the nursery phase.

b. Percentage of sites by combination of production phases and by region:

 Percent Sites 

 Region 

North 

West 

Central 

East 

Central South All Sites 

Production Phase 

Combination Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

All four phases 30.2 (2.7) 33.4 (2.9) 25.8 (1.8) 8.0 (1.6) 26.4 (1.2) 

Gestation, 

farrowing, and 

nursery 2.4 (0.8) 4.1 (1.1) 4.2 (0.9) 3.3 (0.4) 3.7 (0.5) 

Nursery and 

grower/finisher 11.8 (1.6) 11.9 (1.9) 21.0 (1.5) 1.6 (1.0) 15.3 (0.9) 

Gestation and 

farrowing 3.8 (0.9) 7.1 (1.7) 6.9 (1.0) 20.7 (2.5) 7.6 (0.7) 

Nursery only 6.9 (1.3) 7.3 (1.6) 5.8 (0.8) 20.6 (2.4) 7.8 (0.6) 

Grower/finisher 

only 42.0 (2.7) 31.6 (2.9) 35.1 (1.8) 43.9 (3.1) 36.9 (1.2) 

Other combination 2.9 (1.2) 4.6 (1.3) 1.2 (0.5) 1.9 (1.0) 2.3 (0.4) 

Total 100.0 100.0 100.0 100.0 100.0 
Section I: Population Estimates

36 / Swine 2006

0

10

20

30

40

26.4

3.7

15.3

7.6 7.8

36.9

2.3

All four

phases

Gestation,

farrowing,

and nursery

Nursery

and

grower/

finisher

Gestation

and

farrowing

Nursery

only

Grower/

finisher

only

Other

combination

Production Phase

Percent

Percentage of Sites by Combination of Production Phases

2. Facility type

Total confinement was the most common type of facility for all phases, except

gestation. Over half of grower/finisher sites (53.2 percent) had total confinement,

and nearly three-fourths of sites (74.0 percent) with a nursery had total

confinement. Most pigs were kept in total confinement housing for all four phases

(table b). Although a similar percentage of sites had their gestation phase in either

total confinement (34.6 percent) or in an open building with outside access (37.3

percent) [table a], the highest percentage of breeding pigs in the gestation phase

(79.7 percent) were kept in total confinement (table b).
USDA APHIS VS / 37

 Section I: Population Estimates

a. For sites with the specified production phases, percentage of sites by facility

type used most:

Percent Sites 

Production Phase 

 Gestation Farrowing Nursery

Grower/ 

Finisher 

Facility Type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Total confinement 34.6 (1.9) 67.7 (2.1) 74.0 (1.7) 53.2 (1.4) 

Open building with 

no outside access 13.3 (1.5) 10.6 (1.4) 10.7 (1.2) 20.4 (1.2) 

Open building with 

outside access 37.3 (2.2) 15.1 (1.7) 11.3 (1.3) 23.3 (1.4) 

Lot with hut or no 

building 8.6 (1.2) 3.3 (0.7) 1.8 (0.5) 1.8 (0.4) 

Pasture with hut or 

no building 6.2 (1.0) 3.3 (0.8) 2.2 (0.6) 1.3 (0.3) 

Total 100.0 100.0 100.0 100.0 

0

20

40

60

80

Farrowing

Gestation

34.6

67.7

13.3

10.6

37.3

15.1

8.6

3.3

6.2

3.3

Total

confinement

Open building

with no

outside access

Open building

with outside

access

Lot with hut

or no building

Pasture with

hut or no

building

Facility Type

Production Phase

Percent

For Sites with the Specified Production Phases, Percentage of Sites by

Facilty Type Used Most
Section I: Population Estimates

38 / Swine 2006

b. For sites with the specified production phases, percentage of pigs on these

sites by facility type used most:

0

20

40

60

80

100

Farrowing

Gestation

Total

confinement

Open building

with no

outside access

Open building

with outside

access

Lot with hut

or no building

Pasture with

hut or no

building

Facility Type

Production Phase

Percent

For Sites with the Specified Production Phases, Percentage of Pigs on These

Sites by Facility Type Used Most

79.7

87.8

12.8 10.1

5.6

1.4 1.1 0.3 0.8 0.4

Percent Pigs 

Production Phase 

 Gestation1 Farrowing1 Nursery2

Grower/ 

Finisher3

Facility Type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Total confinement 79.7 (2.9) 87.8 (2.6) 90.4 (1.6) 81.0 (1.3) 

Open building with 

no outside access 12.8 (2.7) 10.1 (2.6) 8.0 (1.6) 13.5 (1.1) 

Open building with 

outside access 5.6 (0.7) 1.4 (0.2) 1.0 (0.2) 5.1 (0.5) 

Lot with hut or no 

building 1.1 (0.2) 0.3 (0.1) 0.1 (0.0) 0.2 (0.1) 

Pasture with hut or 

no building 0.8 (0.2) 0.4 (0.1) 0.5 (0.2) 0.2 (0.0) 

Total 100.0 100.0 100.0 100.0 

1

As a percentage of sows and gilts that farrowed. 

2

As a percentage of pigs entering the nursery phase. 

3

As a percentage of pigs entering the grower/finisher phase. 
USDA APHIS VS / 39

 Section I: Population Estimates

The highest percentage of sites with farrowing, nursery, or grower/finisher phases

(54.0, 65.5, and 42.3 percent of sites, respectively) used completely slatted

flooring. For sites with a gestation phase, the highest percentage used solid

surface flooring, followed by dirt, and partial slats (mixed flooring of solid and

slats).

c. For sites with the specified production phases, percentage of sites by flooring

type used most:

Percent Sites 

Production Phase 

 Gestation Farrowing Nursery

Grower/ 

Finisher 

Flooring Type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Solid surface 35.6 (2.2) 23.2 (2.0) 16.7 (1.5) 28.0 (1.4) 

Partial slats 23.5 (1.7) 13.3 (1.4) 12.4 (1.2) 23.1 (1.3) 

Completely slatted 14.9 (1.4) 54.0 (2.1) 65.5 (1.8) 42.3 (1.3) 

Dirt 26.0 (1.9) 9.5 (1.2) 5.4 (0.8) 6.6 (0.7) 

Total 100.0 100.0 100.0 100.0 

While 26.0 percent of sites had dirt flooring in the gestation phase (table c), these

sites accounted for only 3.7 percent of pigs (table d).

d. For sites with the specified production phases, percentage of pigs by flooring

type used most:

Percent Pigs 

Production Phase 

 Gestation1 Farrowing1 Nursery2

Grower/ 

Finisher3

Flooring Type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Solid surface 10.8 (3.0) 2.3 (0.3) 2.5 (0.5) 7.8 (0.7) 

Partial slats 48.4 (4.2) 13.2 (3.0) 8.8 (1.5) 16.8 (1.3) 

Completely slatted 37.1 (4.2) 83.1 (3.1) 87.9 (1.6) 74.5 (1.6) 

Dirt 3.7 (0.5) 1.4 (0.5) 0.8 (0.3) 0.9 (0.1) 

Total 100.0 100.0 100.0 100.0 

1

As a percentage of sows and gilts that farrowed. 

2

As a percentage of pigs entering the nursery phase. 

3

As a percentage of pigs entering the grower/finisher phase.
Section I: Population Estimates

40 / Swine 2006

For sites with slatted flooring (partial slats or completely slatted), the highest

percentage of sites with a gestation or grower/finisher phase used concrete slats

(87.1 and 95.6 percent of sites, respectively). Most sites with slatted flooring that

had a farrowing or nursery phase used metal slats (73.3 and 47.0 percent of sites,

respectively).

e. For sites with the specified production phases and slatted flooring, percentage

of sites by flooring material used most:

Percent Sites 

Production Phase 

 Gestation Farrowing Nursery

Grower/ 

Finisher 

Flooring Material Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Concrete 87.1 (2.0) 13.0 (1.7) 20.1 (1.6) 95.6 (0.7) 

Metal 11.1 (1.9) 73.3 (2.2) 47.0 (2.0) 3.1 (0.6) 

Plastic 1.8 (0.7) 12.5 (1.7) 29.5 (1.8) 1.1 (0.4) 

Other 0.0 (--) 1.2 (0.4) 3.4 (0.6) 0.2 (0.1) 

Total 100.0 100.0 100.0 100.0 

f. For sites with the specified production phases and slatted flooring, percentage of

pigs by flooring material used most:

Percent Pigs 

Production Phase 

 Gestation1 Farrowing1 Nursery2

Grower/ 

Finisher3

Flooring Material Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Concrete 94.4 (1.5) 19.0 (4.1) 19.1 (3.1) 97.5 (0.5) 

Metal 4.7 (1.4) 70.5 (4.5) 38.2 (3.4) 1.6 (0.4) 

Plastic 0.9 (0.4) 7.3 (1.4) 31.7 (2.8) 0.8 (0.3) 

Other 0.0 (--) 3.2 (2.0) 11.0 (2.5) 0.1 (0.1) 

Total 100.0 100.0 100.0 100.0 

1

As a percentage of sows and gilts that farrowed. 

2

As a percentage of pigs entering the nursery phase. 

3

As a percentage of pigs entering the grower/finisher phase.
USDA APHIS VS / 41

 Section I: Population Estimates

3. Pig flow

Continuous flow was the management style used in the gestation phase by the

highest percentage of sites and for the highest percentage of pigs (61.5 percent

and 77.0 percent, respectively) [tables a and b]. Although for the farrowing phase

similar percentages of sites used continuous flow and all-in/all-out management

by room, the highest percentage of farrowing sows (73.4 percent) were managed

all-in/all-out by room (table b). The highest percentage of sites with a grower/

finisher phase used all-in/all-out by building (35.0 percent of sites), and the highest

percentage of pigs in grower/finisher phase were managed all-in/all-out by building

(52.6 percent of pigs) [tables a and b].

a. For sites with the specified production phases, percentage of sites by pig-flow

management style:

Percent Sites 

Production Phase 

 Gestation Farrowing Nursery

Grower/ 

Finisher 

Management Style Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Continuous flow 61.5 (2.1) 33.5 (2.1) 25.0 (1.7) 26.1 (1.3) 

All swine removed 

without cleaning and 

disinfecting 4.6 (1.0) 4.7 (1.1) 3.6 (0.8) 6.2 (0.8) 

All-in/all-out by 

room, with room 

cleaned and 

disinfected 10.0 (1.3) 37.1 (2.0) 30.5 (1.6) 17.5 (1.2) 

All-in/all-out by 

building, with 

building cleaned and 

disinfected 7.7 (1.2) 16.1 (1.6) 29.8 (1.6) 35.0 (1.3) 

All-in/all-out by site, 

with site cleaned 

and disinfected 1.4 (0.5) 1.9 (0.6) 7.1 (1.0) 12.1 (1.0) 

Not applicable (no 

housing) 14.8 (1.5) 6.7 (1.0) 4.0 (0.7) 3.1 (0.5) 

Total 100.0 100.0 100.0 100.0 
Section I: Population Estimates

42 / Swine 2006

b. For sites with the specified production phases, percentage of pigs on these

sites by pig- flow management style:

Percent Pigs 

Production Phase 

 Gestation1 Farrowing1 Nursery2

Grower/ 

Finisher3

Management Style Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Continuous flow 77.0 (3.7) 15.1 (2.5) 8.4 (1.4) 10.9 (1.2) 

All swine removed 

without cleaning and 

disinfecting 1.2 (0.4) 0.8 (0.4) 0.7 (0.2) 1.8 (0.3) 

All-in/all-out by 

room, with room 

cleaned and 

disinfected 14.9 (2.9) 73.4 (3.5) 38.3 (3.0) 18.1 (1.7) 

All-in/all-out by 

building, with 

building cleaned and 

disinfected 4.6 (2.6) 8.3 (2.6) 38.3 (3.4) 52.6 (2.2) 

All-in/all-out by site, 

with site cleaned 

and disinfected 0.4 (0.1) 1.7 (1.3) 13.7 (3.0) 16.2 (1.7) 

Not applicable (no 

housing) 1.9 (0.3) 0.7 (0.1) 0.6 (0.2) 0.4 (0.1) 

Total 100.0 100.0 100.0 100.0 

1

As a percentage of sows and gilts that farrowed. 

2

As a percentage of pigs entering the nursery phase. 

3

As a percentage of pigs entering the grower/finisher phase.
USDA APHIS VS / 43

 Section I: Population Estimates

Most sites with nursery or grower/finisher phases that did not use continuous-flow

management had only one age group of nursery or grower/finisher pigs at one

time.

c. For sites with nursery or grower/finisher phases not managed by continuous

flow, percentage of sites by number of distinct age groups on-site at one time:

Photo courtesy of National Pork Board

Percent Sites 

Production Phase 

Nursery Grower/Finisher 

Number of 

Age Groups Percent Std. Error Percent Std. Error 

1 66.0 (1.9) 63.1 (1.6) 

2 17.2 (1.6) 15.5 (1.2) 

3 or more 16.8 (1.4) 21.4 (1.4) 

Total 100.0 100.0 
Section I: Population Estimates

44 / Swine 2006

4. Multiple-site production

Multiple-site production involves moving pigs to a separate site/location between

phases of production. Just over 4 of 10 sites (41.3 percent) moved pigs from the

farrowing site to a separate nursery site, and nearly 5 of 10 sites (48.2 percent)

moved pigs from the nursery site to a separate grower/finisher site. Use of

separate sites from farrowing to nursery increased as size of site increased.

a. For sites with the specified production phases, percentage of sites that moved

pigs from one site to a separate site as pigs changed production phases, by size

of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Moved from . . . Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Farrowing to 

separate nursery 

site 34.9 (2.4) 58.3 (5.2) 74.8 (3.6) 41.3 (2.1) 

Nursery to 

separate 

grower/finisher 

site 43.5 (2.3) 61.9 (2.9) 57.9 (4.2) 48.2 (1.8) 

Farrowing to 

separate nursery 

and from nursery 

to separate 

grower/finisher 

site 28.2 (2.6) 32.9 (5.0) 51.6 (5.2) 30.2 (2.3) 
USDA APHIS VS / 45

 Section I: Population Estimates

0

20

40

60

80

100

Large (5,000 or more)

Medium (2,000-4,999)

Small (fewer than 2000)

Percent

From farrowing to

separate nursery site

From nursery to separate

grower/finisher site

From farrowing to

separate nursery and

from nursery to separate

grower/finisher site

For Sites with the Specified Production Phases, Percentage of Sites that Moved

Pigs from One Site to a Separate Site as Pigs Changed Production Phases,

by Size of Site:

34.9

43.5

28.2

58.3

61.9

32.9

74.8

57.9

51.6

Size of Site (Total Inventory)

Phase

Large sites were more likely to wean piglets at an average of 20 days or less and

move pigs to a separate nursery site compared to small sites.

b. For sites with a farrowing phase, percentage of sites that weaned pigs at an

average age of 20 days or less, removed pigs to a separate nursery site, or did

both, by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Measure Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Weaned pigs at 

average age of 

20 days or less 15.9 (1.8) 65.0 (5.4) 75.3 (5.0) 26.8 (1.8) 

Removed pigs 

to separate 

nursery site 34.9 (2.4) 58.3 (5.2) 74.8 (3.6) 41.3 (2.1) 

Both 8.4 (1.3) 37.6 (5.7) 57.9 (5.3) 16.3 (1.4) 
Section I: Population Estimates

46 / Swine 2006

A higher percentage of piglets on large sites were weaned at an average of 20

days or less and removed to a separate nursery site compared to piglets on small

sites.

c. For sites with a farrowing phase, percentage of piglets weaned on sites that

weaned at an average age of 20 days or less, removed to a separate-site nursery,

or both, by size of site:

5. Source of sows and gilts

From December 2005 through May 2006, 93.7 percent of small sites with a

gestation phase brought sows and gilts already on their sites into their gestation

phase. A higher percentage of medium and large sites (19.4 and 19.7 percent,

respectively) introduced sows and gilts obtained from other pig producers

compared to small sites (8.2 percent). The percentage of sows and gilts entering

the gestation phase followed a similar pattern (table b).

Percent Pigs 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Measure Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Weaned pigs at 

average age of 

20 days or less 49.5 (3.9) 72.1 (10.1) 85.6 (4.2) 75.7 (3.6) 

Removed pigs to 

separate site 

nursery 56.0 (3.7) 70.1 (8.9) 83.8 (3.0) 75.3 (3.0) 

Both 35.7 (4.2) 44.5 (9.4) 72.3 (5.0) 59.0 (4.2) 
USDA APHIS VS / 47

 Section I: Population Estimates

a. For sites with a gestation phase, percentage of sites that brought or placed any

sows and gilts into the gestation phase from December 2005 through May 2006,

by source of sows and gilts and by size of site:

Percent Sites 

Size of Site (Number Sows and Gilts)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Source Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

On-site 93.7 (1.5) 78.8 (5.5) 75.1 (4.0) 89.2 (1.4) 

Another site 

belonging to 

same operation 2.4 (1.0) 5.1 (4.2) 15.6 (4.2) 4.8 (1.1) 

Other pig 

producer(s) 8.2 (1.5) 19.4 (4.5) 19.7 (3.4) 11.1 (1.4) 

Auction/sale 

barn/livestock 

market 1.7 (0.7) 0.5 (0.4) 0.4 (0.4) 1.4 (0.5) 

Other 1.2 (0.7) 0.0 (--) 2.7 (1.2) 1.3 (0.6) 

0

20

40

60

80

100

Large

Medium

Small

For Sites with a Gestation Phase, Percentage of Sites that Brought or

Placed Any Sows and Gilts Into the Gestation Phase from December 2005

through May 2006, by Source of Sows and Gilts and by Size of Site

Percent

Source

On-site Another site

belonging

to same operation

Other pig

producer(s)

Auction/sale barn/

livestock market

Other

1.7 0.4

75.1

1.2 0.0

Size of Site (Number Sows and Gilts)

93.7

78.8

2.4 5.1

15.6

8.2

19.4 19.7

0.5 2.7
Section I: Population Estimates

48 / Swine 2006

b. For sites with a gestation phase, percentage of sows and gilts entering the

gestation phase from December 2005 through May 2006, by source of sows and

gilts and by size of site:

The majority of sites with a farrowing phase (92.7 percent) obtained sows on-site.

c. For sites with a farrowing phase, percentage of sites that brought or placed any

sows and gilts into the farrowing phase from December 2005 through May 2006,

by source of sows and gilts and by size of site:

Percent Sows and Gilts 

Size of Site (Number Sows and Gilts)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Source Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

On-site 88.6 (3.0) 76.0 (5.7) 74.2 (5.2) 76.0 (4.3) 

Another site 

belonging to 

same operation 2.5 (1.6) 6.0 (4.8) 11.3 (4.9) 9.9 (4.1) 

Other pig 

producer(s) 6.3 (2.1) 17.3 (4.1) 12.1 (2.9) 11.8 (2.4) 

Auction/sale 

barn/livestock 

market 0.4 (0.2) 0.7 (0.6) 0.2 (0.1) 0.2 (0.1) 

Other 2.2 (1.8) 0.0 (--) 2.2 (1.1) 2.1 (0.9) 

Total 100.0 100.0 100.0 100.0 

Percent Sites 

Size of Site (Number Sows and Gilts)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Source Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

On-site 95.1 (1.3) 85.0 (4.3) 86.5 (3.4) 92.7 (1.2) 

Another site 

belonging to 

same operation 1.6 (0.9) 0.0 (--) 10.1 (4.0) 3.0 (1.0) 

Other pig 

producer(s) 5.6 (1.3) 17.7 (4.5) 10.2 (2.5) 7.5 (1.1) 

Auction/sale 

barn/livestock 

market 0.9 (0.4) 0.0 (--) 0.4 (0.4) 0.8 (0.3) 

Other 0.8 (0.6) 0.0 (--) 1.3 (0.7) 0.8 (0.5) 
USDA APHIS VS / 49

 Section I: Population Estimates

The majority of sows and gilts entering the farrowing phase (84.6 percent) were

obtained on-site.

d. Percentage of sows and gilts entering the farrowing phase from December 2005

through May 2006, by source of sows and gilts and by size of site:

Percent Sows and Gilts 

Size of Site (Number Sows and Gilts)

Small 

(Fewer 

than 250) 

Medium 

(250-499) 

Large 

(500 or More) All Sites 

Source Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

On-site 93.2 (2.2) 82.7 (4.3) 83.6 (4.8) 84.6 (4.0) 

Another site 

belonging to 

same operation 0.6 (0.3) 0.0 (--) 8.2 (4.7) 6.8 (3.9) 

Other pig 

producer(s) 3.5 (1.0) 17.3 (4.3) 6.5 (2.0) 6.8 (1.7) 

Auction/sale 

barn/livestock 

market 0.4 (0.3) 0.0 (--) 0.1 (0.1) 0.2 (0.1) 

Other 2.3 (2.0) 0.0 (--) 1.6 (1.0) 1.6 (0.9) 

Total 100.0 100.0 100.0 100.0 
Section I: Population Estimates

50 / Swine 2006

6. Source of nursery pigs

From December 2005 through May 2006, a higher percentage of small sites (69.3

percent) brought pigs into the nursery phase from their own farrowing or nursery

units than medium and large sites (22.9 and 33.8 percent, respectively). Over 6 of

10 medium sites (65.8 percent) and five of 10 large sites (52.1 percent) obtained

pigs for the nursery phase from another producer, while less than 3 of 10 small

sites did so (25.0 percent).

a. For sites with a nursery phase, percentage of sites that brought or placed any

pigs into the nursery phase from December 2005 through May 2006, by source of

pigs and by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Source Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

On-site farrowing 

or nursery units 69.3 (2.1) 22.9 (2.3) 33.8 (3.4) 56.9 (1.7) 

Another 

farrowing or 

nursery unit 

belonging to 

same operation 7.4 (1.4) 10.7 (2.1) 15.2 (4.5) 8.9 (1.2) 

Another 

producer 25.0 (1.9) 65.8 (2.8) 52.1 (4.2) 35.4 (1.6) 

Auction, sale 

barn, or livestock 

market 0.8 (0.4) 0.5 (0.5) 0.0 (--) 0.7 (0.3) 

Other 0.0 (0.0) 0.9 (0.3) 0.4 (0.3) 0.2 (0.1) 
USDA APHIS VS / 51

 Section I: Population Estimates

0

20

40

60

80

Large (5,000 or more)

Medium (2,000-4,999)

Small (fewer than 2,000)

For Sites With a Nursery Phase, Percentage of Sites that Brought or Placed any

Pigs Into the Nursery Phase from December 2005 through May 2006, by Source

of Pigs and by Size of Site:

Percent

Source

Size of Site (Total Inventory)

69.3

22.9

33.8

7.4

10.7

15.2

25.0

65.8

52.1

0.8 0.5 0.0 0.0 0.9 0.4

On-site farrowing

or nursery units

Another farrowing

or nursery unit

belonging to same

operation

Another

producer

Auction, sale

barn, or

livestock market

Other
Section I: Population Estimates

52 / Swine 2006

Although the highest percentage of sites obtained nursery pigs from on-site

farrowing or nursery units (table a), the highest percentage of pigs (57.0 percent)

came from another producer.

b. Percentage of pigs that entered the nursery phase from December 2005

through May 2006, by source of pigs and by size of site:

Percent Pigs 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Pigs 

Source Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

On-site farrowing 

or nursery units 40.5 (2.8) 13.3 (1.7) 28.5 (4.2) 26.7 (2.4) 

Another 

farrowing or 

nursery unit 

belonging to 

same operation 13.9 (3.0) 12.6 (2.2) 17.8 (6.2) 15.7 (3.5) 

Another 

producer 44.9 (3.1) 73.0 (2.6) 53.4 (5.5) 57.0 (3.2) 

Auction, sale 

barn, or livestock 

market 0.7 (0.3) 0.3 (0.3) 0.0 (--) 0.2 (0.1) 

Other 0.0 (0.0) 0.8 (0.4) 0.3 (0.2) 0.4 (0.2) 

Total 100.0 100.0 100.0 100.0 
USDA APHIS VS / 53

 Section I: Population Estimates

The percentage of sites that obtained nursery pigs off-site and used just one

source ranged from 66.0 percent of large sites to 88.5 percent of small sites. The

percentage of sites using three or more sources to obtain nursery pigs ranged

from 25.4 percent of large sites to 4.4 percent of small sites.

c. For sites that obtained any nursery pigs from off-site, percentage of sites by

number of different sources and by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Number of 

Sources Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

1 88.5 (2.5) 80.6 (2.4) 66.0 (6.3) 81.9 (2.0) 

2 7.1 (2.2) 9.5 (1.8) 9.5 (3.3) 8.3 (1.4) 

3 2.1 (1.0) 4.5 (1.3) 12.1 (4.3) 4.7 (1.1) 

4 to 5 1.3 (0.6) 2.6 (1.1) 2.3 (1.0) 1.9 (0.5) 

6 or more 1.0 (0.8) 2.8 (0.7) 10.1 (5.7) 3.2 (1.2) 

Total 100.0 100.0 100.0 100.0 

Only 13.6 percent of sites with off-site sources immediately placed new nursery

pigs with existing pigs. The percentages were similar across size groups.

d. For sites that obtained any nursery pigs from off-site, percentage of sites that

immediately placed these pigs in the same building or area as existing pigs, by

size of site.

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

13.9 (2.9) 10.3 (2.0) 18.0 (5.8) 13.6 (2.0) 
Section I: Population Estimates

54 / Swine 2006

7. Source of grower/finisher pigs

A higher percentage of small sites (54.7 percent) brought or placed new nursery

pigs from their own nursery units into the grower/finisher phase from December

2005 through May 2006 than did medium and large sites (36.3 and 42.7 percent,

respectively).

a. For sites with a grower/finisher phase, percentage of sites that brought or

placed any pigs into the grower/finisher phase from December 2005 through May

2006, by source of pigs and by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Source Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

On-site 54.7 (1.9) 36.3 (2.2) 42.7 (3.2) 49.9 (1.5) 

Another site 

belonging to 

same operation 10.3 (1.2) 14.9 (1.9) 15.7 (3.4) 11.8 (1.0) 

Other pig 

producer(s) 35.1 (1.9) 47.9 (2.4) 41.4 (3.4) 38.2 (1.4) 

Auction, sale 

barn, or livestock 

market 2.2 (0.6) 1.1 (0.6) 0.6 (0.4) 1.8 (0.4) 

Other 0.4 (0.3) 1.7 (0.6) 0.9 (0.6) 0.7 (0.3) 
USDA APHIS VS / 55

 Section I: Population Estimates

0

20

40

60

80

Large (5,000 or more)

Medium (2,000-4,999)

Small (fewer than 2,000)

For Sites With a Grower/finisher Phase, Percentage of Sites that Brought or

Placed any Pigs Into the Grower/Finisher Phase from December 2005 through

May 2006, by Source of Pigs and by Size of Site:

Percent

Source

Size of Site (Total Inventory)

On-site farrowing

or nursery units

Off-site farrowing

or nursery units

belonging to same

operation

Another

producer

Auction, sale

barn, or

livestock market

Other

54.7

36.3

42.7

10.3

14.9 15.7

35.1

47.9

41.4

2.2 1.1 0.6 0.4 1.7 0.9
Section I: Population Estimates

56 / Swine 2006

On small and large sites, a higher percentage of grower/finisher pigs (39.6 and

41.5 percent, respectively) came from on-site compared to medium sites

(27.4 percent).

b. Percentage of pigs that entered the grower/finisher phase from December 2005

through May 2006, by source of pigs and by size of site:

Percent Pigs 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Pigs 

Source Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

On-site 39.6 (2.2) 27.4 (2.1) 41.5 (4.4) 36.5 (2.0) 

Another site 

belonging to 

same operation 14.2 (1.9) 19.2 (2.8) 18.7 (5.8) 17.8 (2.7) 

Other pig 

producer(s) 44.2 (2.3) 51.2 (2.7) 38.4 (4.2) 43.9 (2.2) 

Auction, sale 

barn, or livestock 

market 1.1 (0.3) 0.5 (0.2) 0.3 (0.2) 0.5 (0.1) 

Other 0.9 (0.6) 1.7 (0.7) 1.1 (0.8) 1.3 (0.4) 

Total 100.0 100.0 100.0 100.0 
USDA APHIS VS / 57

 Section I: Population Estimates

For sites that obtained grower/finisher pigs off-site, 37.3 percent of large sites,

14.3 percent of medium sites, and 5.0 percent of small sites obtained grower/

finisher pigs from three or more off-site sources.

c. For sites that obtained any grower/finisher pigs from off-site, percentage of sites

by number of different sources and by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Number of 

Sources Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

1 86.6 (1.8) 72.3 (2.8) 47.9 (5.1) 78.6 (1.6) 

2 8.4 (1.5) 13.4 (2.0) 14.8 (3.2) 10.4 (1.2) 

3 3.0 (0.9) 7.7 (1.9) 20.1 (5.5) 6.1 (1.0) 

4 to 5 1.9 (0.7) 5.1 (1.2) 9.6 (2.6) 3.6 (0.6) 

6 or more 0.1 (0.0) 1.5 (0.7) 7.6 (2.8) 1.3 (0.4) 

Total 100.0 100.0 100.0 100.0 

About 1 of 5 sites that obtained grower/finisher pigs from off-site sources (18.3

percent), immediately placed these pigs with existing pigs.

d. For sites that obtained any grower/finisher pigs from off-site, percentage of sites

that immediately placed these pigs in the same building or area as existing pigs,

by size of site.

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

22.3 (2.5) 9.9 (2.5) 13.3 (5.3) 18.3 (1.8) 
Section I: Population Estimates

58 / Swine 2006

F. Disease Prevention

and Vaccination—All

Phases

1. Disease prevention

Deworming was the disease preventive practice used most frequently for sows and

boars from December 2005 through May 2006 (76.8 percent and 68.2 percent of

sites, respectively). In preweaned piglets, administration of iron (usually given at 7

to 10 days of age) was the most common preventive practice. Approximately 8 of

10 sites (79.6 percent) used antibiotics in feed as a preventive practice for nursery

pigs. Antibiotics in feed was also the most common preventive practice used for

grower/finisher pigs, and it was the second most common practice used for piglets

after iron shot.

a. For sites with the specified pig type, percentage of sites by disease preventive

practices regularly used from December 2005 through May 2006:

Percent Sites 

Pig Type 

 Sows Boars 

Piglets 

(Before or 

at Weaning) Nursery 

Grower/ 

Finisher 

Practice Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Deworm 76.8 (1.9) 68.2 (2.0) 47.2 (2.2) 37.1 (1.8) 34.0 (1.4) 

Mange/lice 

treatment 52.8 (2.2) 51.3 (2.2) 36.5 (2.2) 25.9 (1.7) 17.8 (1.2) 

Iron N/A N/A 80.1 (1.8) N/A N/A 

Antibiotics in feed 47.7 (2.2) 34.5 (2.2) 60.0 (2.1) 79.6 (1.5) 68.1 (1.4) 

Antibiotics in water 3.7 (0.9) 3.8 (0.9) 13.3 (1.5) 36.2 (1.7) 29.0 (1.3) 

Antibiotics (oral) 2.4 (0.7) 2.5 (0.8) 12.2 (1.5) 6.2 (0.9) 4.3 (0.6) 

Antibiotics 

(injection) 40.8 (2.2) 23.2 (1.9) 51.4 (2.2) 40.4 (1.8) 38.8 (1.5) 
USDA APHIS VS / 59

 Section I: Population Estimates

Over two-thirds of sows and boars were on sites that regularly practiced

deworming. Over half of nursery and grower/finisher pigs were on sites that

routinely treated these animals with antibiotics, whether in feed, water, or by

injection. Almost 90 percent of pigs were on sites that administered iron before or

at weaning.

b. For sites with the specified pig type, percentage of pigs on sites by disease

preventive practices regularly used from December 2005 through May 2006:

Percent Pigs 

Pig Type 

 Sows1

 Boars2

Piglets3

(Before or 

at Weaning) Nursery4

Grower/ 

Finisher5

Practice Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Deworm 69.3 (3.8) 76.2 (3.4) 13.1 (2.9) 11.3 (1.1) 14.3 (1.1) 

Mange/lice 

treatment 18.6 (2.0) 57.4 (5.4) 7.4 (1.2) 9.2 (2.7) 5.1 (0.6) 

Iron N/A N/A 89.1 (4.2) N/A N/A 

Antibiotics in feed 46.1 (4.4) 41.1 (7.0) 30.8 (3.9) 89.5 (1.4) 78.2 (1.7) 

Antibiotics in water 5.6 (2.9) 3.4 (1.0) 15.0 (3.9) 63.1 (2.8) 50.6 (2.4) 

Antibiotics (oral) 1.8 (0.6) 2.0 (0.8) 16.8 (4.1) 8.4 (1.6) 4.2 (0.7) 

Antibiotics 

(injection) 51.9 (4.2) 32.0 (7.9) 68.7 (4.6) 64.7 (2.7) 52.7 (2.4) 1

As a percentage of sow and bred gilt inventory on June 1, 2006. 

2

As a percentage of boar inventory on June 1, 2006. 

3

As a percentage of pigs born alive (6 months). 

4

As a percentage of pigs entering nursery (6 months). 

5

As a percentage of pigs entering grower/finisher phase (6 months).
Section I: Population Estimates

60 / Swine 2006

2. Vaccination

From December 2005 through May 2006, over 6 of 10 sites (61.4 percent)

vaccinated any pigs. The highest percentage of sites regularly vaccinated against

Mycoplasma and erysipelas (40.4 and 39.0 percent, respectively). The most

common “other” diseases sites regularly vaccinated against were ileitis and

Salmonella.

Percentage of sites by disease pigs were regularly vaccinated against—regardless

of age of pigs—and by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Disease Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Porcine 

reproductive and 

respiratory 

syndrome 

(PRRS) 20.6 (1.5) 15.0 (1.4) 18.5 (2.6) 19.2 (1.1) 

Erysipelas 41.1 (1.8) 34.3 (2.1) 35.3 (2.8) 39.0 (1.3) 

E. coli scours 27.0 (1.6) 20.9 (1.9) 29.9 (3.0) 26.1 (1.2) 

Parvovirus 31.2 (1.7) 18.6 (1.8) 26.8 (2.7) 28.2 (1.2) 

Leptospirosis 33.8 (1.7) 18.1 (1.8) 25.3 (2.6) 29.6 (1.2) 

Rhinitis 

(Pasteurella, 

Bordetella) 26.3 (1.6) 10.8 (1.4) 9.2 (1.5) 21.1 (1.1) 

Mycoplasma 

(pneumonia) 35.8 (1.7) 46.5 (2.1) 56.0 (2.9) 40.4 (1.3) 

Any influenza 13.4 (1.2) 18.8 (1.9) 29.5 (2.8) 16.5 (1.0) 

Swine flu (H3N2) 7.4 (0.9) 12.9 (1.7) 25.2 (2.7) 10.7 (0.8) 

Traditional swine 

flu (H1N1) 7.1 (0.9) 11.7 (1.7) 23.8 (2.7) 10.1 (0.7) 

Other diseases 5.8 (0.9) 9.6 (1.1) 14.4 (2.3) 7.6 (0.7) 

Did not know 

which vaccines 

were given 3.4 (0.7) 4.9 (0.8) 3.1 (1.4) 3.6 (0.5) 

Any vaccination 58.1 (1.8) 65.8 (2.0) 72.1 (2.8) 61.4 (1.3) 
USDA APHIS VS / 61

 Section I: Population Estimates

0 10 20 30 40 50

PRRS

Erysipelas

E. coli scours

Parvovirus

Leptospirosis

Rhinitis

Mycoplasma

Any influenza

Swine flu

(H3N2)

Traditional swine

flu (H1N1)

Other diseases

Did not know which

vaccines were given

Disease

Percent

Percentage of Sites by Disease Pigs were Regularly Vaccinated Against,

Regardless of Age of Pigs

19.2

39.0

26.1

28.2

29.6

21.1

40.4

16.5

10.7

10.1

7.6

3.6
Section I: Population Estimates

62 / Swine 2006

3. Use of a veterinarian

Approximately 7 of 10 sites (69.1 percent) used a veterinarian during the previous

year. A higher percentage of large and medium sites (88.1 and 85.0 percent,

respectively) used a veterinarian during the previous year compared to small sites

(60.8 percent). Nearly five of 10 large sites (46.8 percent) used an on-staff

veterinarian. A similar percentage of large sites (42.5 percent) used a local

practitioner. Overall, approximately half of sites (49.5 percent) used a local

practioner during the previous 12 months.

a. Percentage of sites where a veterinarian visited for any purpose during the

previous 12 months, by type of veterinarian and by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Type of 

Veterinarian Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Local practitioner 51.2 (1.8) 48.2 (2.1) 42.5 (3.4) 49.5 (1.4) 

Consulting or 

second-opinion 7.4 (0.9) 19.0 (2.0) 24.5 (3.6) 11.9 (1.0) 

On-staff 7.7 (0.8) 35.2 (2.0) 46.8 (3.0) 18.0 (0.9) 

State or Federal 1.3 (0.5) 1.4 (0.6) 0.6 (0.3) 1.2 (0.4) 

Other type 0.4 (0.2) 1.8 (0.8) 4.5 (2.4) 1.2 (0.4) 

Any type 60.8 (1.7) 85.0 (1.4) 88.1 (1.7) 69.1 (1.3) 
USDA APHIS VS / 63

 Section I: Population Estimates

0

20

40

60

80

100

Large (5,000 or more

Medium (2,000-4,999)

Small (fewer than 2,000)

51.2

48.2

42.5

7.4

19.0

24.5

7.7

35.2

46.8

1.3 1.4 0.6 0.4 1.8

4.5

Local

practitioner

Consulting or

second-opinion

veterinarian

On-staff

veterinarian

State or Federal

veterinarian

Other type

Percent

Veterinarian Type

Size of Site (Total Inventory)

Percentage of Sites Where a Veterinarian Visited for Any Purpose During the

Previous 12 Months, by Type of Veterinarian

60.8

85.0

88.1

Any type
Section I: Population Estimates

64 / Swine 2006

Percent Sites 

Number Visits 

0 1 2-4 5 or more 

Type of 

Veterinarian Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Total 

Local practitioner 50.5 (1.4) 13.6 (1.0) 19.2 (1.1) 16.7 (1.0) 100.0 

Consulting or 

second-opinion 

veterinarian 88.1 (1.0) 3.4 (0.5) 6.4 (0.8) 2.1 (0.3) 100.0 

On-staff 

veterinarian 82.0 (0.9) 6.7 (0.5) 6.4 (0.5) 4.9 (0.7) 100.0 

State or Federal 

veterinarian 98.8 (0.4) 0.8 (0.2) 0.3 (0.2) 0.1 (0.1) 100.0 

Other type 98.8 (0.4) 0.4 (0.2) 0.6 (0.4) 0.2 (0.1) 100.0 

Any type 30.9 (1.3) 17.4 (1.0) 27.0 (1.2) 24.7 (1.2) 100.0 

About one of four sites (24.7 percent) were visited by a veterinarian five or more

times.

b. Percentage of sites by number of times a veterinarian visited for any purpose

during the previous 12 months, and by type of veterinarian:
USDA APHIS VS / 65

 Section I: Population Estimates

Producers used the services of a veterinarian for many purposes during the

previous 12 months. For sites that had at least one veterinary visit during the

previous 12 months, the highest percentage of sites used a veterinarian to treat

individual pigs (63.8 percent) and to provide drugs or vaccines (62.6 percent). A

higher percentage of large sites used a veterinarian for blood testing, production

record analysis, employee education, and quality assurance compared to small

sites.

c. For sites that had at least one veterinary visit during the previous 12 months,

percentage of sites by purpose of visit:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Purpose Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Individual pig 

treatment or 

surgery, including 

diagnostic 

services 62.5 (2.2) 65.0 (2.2) 66.9 (3.6) 63.8 (1.6) 

Nutritional 

consultation 16.7 (1.7) 24.7 (2.0) 24.0 (3.0) 19.8 (1.3) 

Vaccination 

consultation 42.7 (2.4) 54.0 (2.4) 62.5 (3.8) 48.6 (1.7) 

Environmental 

consultation 13.9 (1.6) 27.0 (2.3) 26.2 (4.1) 19.0 (1.4) 

Provide drugs, 

medications, or 

vaccines 59.0 (2.3) 69.8 (2.3) 65.4 (4.1) 62.6 (1.6) 

Provide nutrient 

premixes 4.7 (1.1) 7.0 (1.1) 7.5 (1.5) 5.7 (0.7) 

Slaughter checks 6.9 (1.2) 12.5 (1.5) 19.5 (2.8) 10.3 (1.0) 

Artificial 

insemination, 

breeding 

evaluations 4.9 (1.0) 8.1 (1.5) 11.4 (2.1) 6.7 (0.8) 

Pregnancy 

checking 7.3 (1.3) 6.8 (1.0) 10.6 (2.2) 7.7 (0.9) 

Blood testing 35.3 (2.3) 58.2 (2.4) 77.3 (2.8) 47.6 (1.7) 

Production record 

analysis 11.3 (1.4) 34.9 (2.3) 50.4 (3.4) 23.3 (1.2) 

Employee training/ 

education 8.6 (1.2) 27.3 (2.2) 38.7 (3.8) 18.0 (1.2) 

Quality assurance 36.7 (2.3) 61.3 (2.4) 69.6 (3.2) 47.9 (1.7) 

Other 4.7 (0.9) 3.3 (0.7) 3.6 (1.1) 4.2 (0.6) 
Section I: Population Estimates

66 / Swine 2006

1. Restrictions for entry

More than 8 of 10 sites (81.0 percent) did not allow anyone except employees to

come in contact with areas where swine were housed.

a. Percentage of sites where entry to swine facilities was restricted to employees

only, by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

78.7 (1.5) 87.0 (1.4) 84.0 (2.1) 81.0 (1.1) 

G. Biosecurity

0 20 40 60 80

Individual pig

treatment

Nutritional

consultation

Vaccination

consultation

Environmental

consultation

Provide drugs

or vaccines

Provide

nutrient premixes

Slaughter

checks

Artificial

insemination

Pregnancy

checking

Blood

testing

Production

record analysis

Employee

training

Quality

assurance

Other

63.8

19.8

48.6

19.0

62.6

5.7

10.3

6.7

7.7

47.6

23.3

18.0

47.9

4.2

Purpose

Percent

For Sites That had at Least One Veterinary Visit During the Previous

12 Months, Percentage of Sites by Purpose of Visit
USDA APHIS VS / 67

 Section I: Population Estimates

For sites where nonemployees were allowed to enter swine facilities, 95.4 percent

allowed business visitors (e.g., an electrician), but only 68.1 percent of sites

allowed nonbusiness visitors. A higher percentage of small sites (77.6 percent)

allowed nonbusiness visitors compared to medium and large sites (42.9 and 32.0

percent, respectively).

b. For sites that did not restrict entry to swine facilities to employees only,

percentage of sites by type of visitor allowed and by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Type of Visitor Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Business 94.7 (1.7) 97.6 (1.3) 97.0 (2.8) 95.4 (1.3) 

Nonbusiness 77.6 (3.2) 42.9 (5.6) 32.0 (6.3) 68.1 (2.8) 

When business visitors were allowed to enter swine facilities, about half of sites

(48.4 percent) required visitors to change to clean boots and coveralls before

entering.

c. For sites that allowed entry to business visitors, percentage of sites where

business visitors were required to take the following preventive measures:

Preventive Measure Percent Sites Standard Error 

Shower before entering site 10.3 (1.6) 

Change to clean boots 

and coveralls 48.4 (3.3) 

Wait 24 hrs or longer after 

visiting another hog site 29.5 (2.8) 
Section I: Population Estimates

68 / Swine 2006

Approximately one of four sites (26.5 percent) that allowed nonbusiness visitors

required clean boots and coveralls before entry to swine facilities; 25.7 percent of

sites required nonbusiness visitors that had visited another pig site to wait 24

hours after the visit before entering swine facilities.

d. For sites that allowed entry to nonbusiness visitors, percentage of sites by

preventive measure required of nonbusiness visitors before entering swine

facilities:

Preventive Measure Percent Sites Standard Error 

Shower before entering site 4.3 (1.3) 

Change to clean boots 

and coveralls 26.5 (3.5) 

Wait 24 hrs or longer after 

visiting another hog site 25.7 (3.6) 

2. Trucking

A livestock hauling truck can be a vector for swine pathogens. Slightly more than

half of sites (51.3 percent) allowed trucks or trailers onto sites where pigs were

kept. A higher percentage of large and medium sites (61.1 and 64.9 percent,

respectively) allowed truck or trailers than did small sites (45.5 percent).

a. Percentage of sites that allowed trucks or trailers from commercial livestock

transporters or animal haulers to enter the pig site, by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

45.5 (1.8) 64.9 (2.2) 61.1 (3.5) 51.3 (1.4) 
USDA APHIS VS / 69

 Section I: Population Estimates

For sites that allowed trucks to enter the pig site, large and medium sites more

commonly required cleaning or disinfecting of the inside or outside of the truck

than small sites.

b. For sites that allowed trucks or trailers from commercial livestock transporters

or animal haulers to enter the pig site, percentage of sites by required cleaning

and disinfecting practices for livestock trucks or trailers, and by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Required 

Practice Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Animal area 

inside truck 

cleaned 60.8 (2.6) 85.8 (1.8) 95.4 (1.1) 72.3 (1.7) 

Animal area 

inside truck 

disinfected 49.3 (2.6) 71.8 (2.2) 86.2 (2.1) 60.5 (1.8) 

Outside of truck 

cleaned 48.1 (2.6) 73.1 (2.3) 83.8 (3.8) 59.7 (1.8) 

Outside of truck 

disinfected 34.4 (2.5) 55.0 (2.4) 69.4 (4.0) 44.8 (1.8) 
Section I: Population Estimates

70 / Swine 2006

3. Proximity to other swine sites

Over 80 percent of all sites were less than 3 miles from another site.

Percentage of swine sites by distance to the nearest known swine site, and by

region:

 Percent Sites 

 Region 

North 

West 

Central 

East 

Central South All Sites 

Distance (Miles) Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Less than 0.50 28.3 (2.6) 19.7 (2.5) 33.9 (1.9) 29.5 (3.1) 29.6 (1.3) 

0.50 to 0.99 22.2 (2.4) 16.0 (2.2) 26.5 (1.7) 22.2 (2.7) 23.2 (1.1) 

1.00 to 2.99 29.6 (2.6) 23.0 (2.4) 29.0 (1.9) 23.3 (2.5) 27.5 (1.2) 

3.00 to 4.99 11.1 (1.9) 19.1 (2.4) 7.0 (1.0) 10.0 (1.9) 10.4 (0.8) 

5.00 or more 8.8 (1.5) 22.2 (2.5) 3.6 (0.7) 15.0 (1.7) 9.3 (0.7) 

Total 100.0 100.0 100.0 100.0 100.0 

Photo courtesy of National Pork Board
USDA APHIS VS / 71

 Section I: Population Estimates

4. Rodent control

Rodents are known to be host for pathogens that affect swine and can spread

disease between swine areas. Nearly all sites (97.3 percent) used some manner

of rodent control, and 87.9 percent used bait or poison to control rodents.

Percentage of sites by rodent control method and by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Control Method Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Cats 63.4 (1.7) 32.2 (1.9) 15.6 (2.0) 51.2 (1.3) 

Dogs 33.0 (1.7) 14.8 (1.5) 8.2 (1.7) 26.3 (1.2) 

Traps 21.5 (1.5) 20.1 (1.7) 16.1 (2.0) 20.5 (1.1) 

Bait or poison 84.4 (1.3) 94.6 (1.3) 96.2 (1.0) 87.9 (0.9) 

Professional 

exterminator 4.7 (0.7) 6.8 (1.0) 6.8 (1.2) 5.4 (0.5) 

Other 1.8 (0.5) 2.6 (0.7) 0.3 (0.2) 1.8 (0.4) 

Any 97.0 (0.7) 98.1 (1.1) 97.9 (0.8) 97.3 (0.5) 

5. Feral swine

When coming into contact with other swine, feral swine can transmit diseases

such as brucellosis or pseudorabies. Twenty-five percent of large sites reported

that feral swine were in their county.

a. Percentage of sites where feral swine were present in the county (including wild

boars on hunting clubs or captive on farms), by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer 

than 2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

6.7 (0.8) 12.3 (1.3) 25.0 (2.6) 10.0 (0.7) 
Section I: Population Estimates

72 / Swine 2006

Nearly 7 of 10 sites in the South region (67.9 percent) reported that feral swine

were in their county.

b. Percentage of sites where feral swine were present in the county (including wild

boars on hunting clubs or captive on farms), by region:

Percent Sites 

Region 

North West Central East Central South 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

2.8 (0.8) 6.1 (1.5) 4.4 (0.9) 67.9 (3.4) 

Of sites in counties where feral swine were present, 15.7 percent had seen feral

swine within a half mile of the site during the previous 12 months.

c. For sites in counties where feral swine were present, percentage of sites where

feral swine were seen on the site or within 0.5 mile of the site during the previous

12 months:

Percent Sites Standard Error 

15.7 (2.4) 

For sites where producers actually saw feral swine on-site, only 13.6 of percent of

producers (sites) reported that feral swine had the potential for physical contact

with their pigs.

d. For sites where feral swine were seen on-site, percentage of sites where feral

swine had direct or fence-line contact with swine on-site, or entered into facilities

used to house swine or store feed:

Percent Sites Standard Error 

13.6 (4.7) 
USDA APHIS VS / 73

 Section I: Population Estimates

1. Carcass disposal

From December 2005 through May 2006, 35.0 percent of sites with at least one

death used on-site composting as a method of carcass disposal.

a. For sites with at least one preweaned piglet or older pig death from December

2005 through May 2006, percentage of sites by method of carcass disposal:

H. General Management

Percent Sites 

Sites with at 

Least One 

Preweaned Death 

Sites with at 

Least One 

Weaned and 

Older Death 

Sites with 

Any Deaths 

Method of 

Carcass 

Disposal Percent 

Std. 

Error Percent 

Std. 

Error Percent 

Std. 

Error 

Burial on-site 31.9 (2.1) 25.1 (1.2) 26.3 (1.2) 

Burning on-site 15.2 (1.5) 12.2 (0.9) 13.7 (0.9) 

Renderer pickup 16.5 (1.7) 37.0 (1.3) 35.9 (1.3) 

Composting 

on-site 37.2 (2.2) 33.8 (1.3) 35.0 (1.3) 

Other 3.1 (0.7) 2.3 (0.3) 2.7 (0.4) 
Section I: Population Estimates

74 / Swine 2006

Nearly half of carcasses (45.7 percent) were picked-up by a renderer. About onethird of carcasses (31.3 percent) were disposed of by composting on-site.

b. For sites with at least one preweaned piglet or older pig death from December

2005 through May 2006, percentage of pig deaths by method of carcass disposal:

Percent Pig Deaths 

Sites with at 

Least One 

Preweaned Death 

Sites with at 

Least One 

Weaned and 

Older Death 

Sites with 

Any Deaths 

Method of 

Carcass 

Disposal Percent 

Std. 

Error Percent 

Std. 

Error Percent 

Std. 

Error 

Burial on-site 6.4 (1.1) 8.3 (0.9) 7.2 (0.9) 

Burning on-site 16.9 (3.0) 9.7 (1.3) 14.1 (2.0) 

Renderer pickup 40.6 (5.2) 53.7 (2.8) 45.7 (3.4) 

Composting 

on-site 34.4 (4.6) 26.4 (2.1) 31.3 (3.0) 

Other 1.7 (0.6) 1.9 (0.4) 1.7 (0.5) 

Total 100.0 100.0 100.0 
USDA APHIS VS / 75

 Section I: Population Estimates

2. Records

The type of records swine sites kept varied. Breeding records were the most

common type of records kept (76.9 percent of sites with gestation or farrowing

phases), followed by drug usage (66.2 percent of sites). In general, large and

medium sites kept records on more topics than small sites.

Percentage of sites by type of records kept and by size of site:

Percent Sites 

Size of Site (Total Inventory)

Small 

(Fewer than 

2,000) 

Medium 

(2,000-4,999) 

Large 

(5,000 or More) All Sites 

Record type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Feed intake 49.7 (1.8) 75.4 (1.8) 83.1 (2.1) 59.0 (1.4) 

Drug usage 58.1 (1.8) 81.2 (1.7) 85.8 (2.0) 66.2 (1.3) 

Breeding 

records* 71.6 (2.3) 98.8 (0.6) 98.7 (1.2) 76.9 (1.9) 

Waste disposal 36.0 (1.7) 82.5 (1.8) 92.5 (1.2) 52.3 (1.3) 

Feed-equipment 

maintenance 

records 19.0 (1.3) 26.0 (1.8) 32.7 (3.0) 22.1 (1.1) 

Rodent control 14.6 (1.3) 34.6 (2.1) 47.7 (3.6) 22.7 (1.2) 

*For sites with gestation or farrowing phases. 
Section I: Population Estimates

76 / Swine 2006

3. Marketing and shipments

The majority of sites (56.0 percent) were independent operations and marketed

pigs on their own. These sites accounted for 45.0 percent of total inventory.

a. Percentage of sites, and percentage of total inventory on these sites, by

business and marketing arrangement:

Business and 

Marketing Arrangement 

Percent 

Sites Std. Error 

Percent 

Total 

Inventory Std. Error 

Contract producer 38.3 (1.2) 49.8 (2.1) 

Independent producer—

market on own 56.0 (1.3) 45.0 (2.2) 

Independent producer—

market through a 

cooperative 5.1 (0.7) 4.4 (0.7) 

Other 0.6 (0.2) 0.8 (0.3) 

Total 100.0 100.0 

Nearly all sites (96.7 percent) sold or shipped at least one pig from December

2005 through May 2006.

b. Percentage of sites that sold or shipped at least one pig off-site from December

2005 through May 2006:

Percent Sites Standard Error 

96.7 (0.5) 

One of three sites had at least one shipment cross State lines.

c. For sites that sold or shipped at least one pig off-site from December 2005

through May 2006, percentage of sites that had any shipments cross State lines:

Percent Sites Standard Error 

31.6 (1.3) 
USDA APHIS VS / 77

 Section I: Population Estimates

Although 75.5 percent of sites sold or shipped market hogs, less than half of pigs

sold or shipped (42.9 percent) were sold as market hogs.

d. For sites that sold or shipped at least one pig off-site from December 2005

through May 2006, percentage of sites, and percentage of shipments and

percentage of pigs sold or shipped off-site, by type of pig sold or shipped:

Culls

Breeding animal

Market hogs

Feeder pigs

Nursery piglets 41.1%

14.1%

42.9%

0.9% 1.0%

Pig Type

For Sites that Sold or Shipped at Least One Pig Off-Site from December

2005 Through May 2006, Percentage of Pigs Shipped Off-Site, by Pig Type

Pig Type 

Pct. 

Sites 

Std. 

Error 

Pct. 

Shipments 

Std. 

Error 

Pct. Pigs 

Sold or 

Shipped 

Std. 

Error 

Nursery 

piglets 

less than 

60 lb 17.4 (1.0) 20.3 (2.5) 41.1 (2.5) 

Feeder pigs 

or pigs 60 

to 249 lb 

14.0 (0.9) 

9.0 (1.1) 

14.1 (1.5) 

Market hogs 

or hogs 250 

lb or more 75.5 (1.2) 62.1 (2.4) 42.9 (2.0) 

Breeding 

animal 3.7 (0.5) 2.5 (0.5) 0.9 (0.1) 

Culls 21.8 (1.1) 6.1 (0.4) 1.0 (0.1) 

Total N/A 100.0 100.0 
Section I: Population Estimates

78 / Swine 2006

Nearly two-thirds of shipments (62.7 percent) went directly to slaughter.

e. For sites that sold or shipped at least one pig off-site from December 2005

through May 2006, percentage of shipments by destination:

Destination Percent Shipments Standard Error 

Directly to slaughter 62.7 (2.4) 

Sale/auction 5.3 (0.6) 

Dealer 3.0 (0.4) 

Show/fair 2.2 (1.1) 

Feedlot/feed yard 1.3 (0.2) 

Another operation 15.7 (1.3) 

Another site that is part of 

this operation (e.g., nursery, 

grower) 9.8 (2.7) 

Total 100.0 
USDA APHIS VS / 79

 Section I: Population Estimates

0 20 40 60 80

62.7

5.3

3.0

2.2

1.3

15.7

9.8

Percent

Directly to

slaughter

Sale/

auction

Dealer

Show/fair

Feedlot/

feed yard

Another

operation

Another site that

is part of this

operation

Destination

For Sites That Sold or Shipped at Least One Pig Off Site from December 2005

Through May 2006, Percentage of Shipments by Destination
Section II: Methodology

80 / Swine 2006

Section II: Methodology

A. Needs Assessment During the Needs Assessment phase of the NAHMS Swine 2006 study, input was

sought from stakeholders regarding the critical swine production and healthinformation needs of the swine industry. These stakeholders included producers,

industry associations, researchers, and government agencies. A Needs

Assessment questionnaire (available on request) was developed to facilitate input

by a variety of groups. The primary sources utilized in the Needs Assessment

were the National Pork Board (NPB) and the American Association of Swine

Veterinarians (AASV).

The NPB Needs Assessment questionnaire for NAHMS Swine 2006 was included

in the October 20, 2005, “Pork Leader Letter.” This letter and questionnaire were

distributed by conventional mail and by e-mail to 2,800 and 5,000 subscribers,

respectively.

The AASV Needs Assessment questionnaire for NAHMS Swine 2006 was

included in the November 2, 2005, AASV newsletter. This newsletter was also

distributed by mail and by e-mail to approximately 440 practitioners and 700

newsletter subscribers.

In addition, between November 1 and 30, 2005, a letter of introduction and

questionnaire were e-mailed to government contacts at the Centers for Disease

Control; APHIS in Riverdale, MD; National Veterinary Services Laboratories;

Centers for Epidemiology and Animal Health; regional epidemiologists; area

veterinarians in charge; and the Food Safety Inspection Service. Overall, there

were 528 responses to the Needs Assessment questionnaire.

1. Number of respondents, by respondent type

Nearly half respondents (46.4 percent) characterized themselves as producers.

Respondent Type Frequency Percent Respondents 

Producer 245 46.4 

Practitioner 206 39.0 

Researcher 22 4.2 

Federal or State government 16 3.0 

Other allied industry 21 4.0 

Unknown 18 3.4 

Total 528 100.0 
Section II: Methodology

USDA APHIS VS / 81

B. Sampling

and Estimation

1. State selection

A goal for NAHMS’ national studies is to include States that represent at least 70

percent of the animal and producer population in the United States. This study

focuses on operations with 100 or more hogs. Information from the National

Agricultural Statistics Service (NASS) December 28, 2004, “Hog and Pig” report

for numbers of hogs and pigs and the January 1, 2005, “Farms and Land in Farms”

report for number of operations with 100 or more hogs was used to select States.

The NASS hog and pig estimation program collects data quarterly from producers

in 17 States* and annually in all States. These 17 States accounted for 94.0

percent of the December 1, 2004, U.S. swine inventory for operations with more

than 100 hogs and 94.2 percent of U.S. operations with more than 100 hogs (See

Appendix II for data on individual States, updated to June 1, 2006, inventory and

number of operations in 2006.) An additional advantage of selecting these 17

States is that THE NASS list frame is more complete due to the more frequent

contact with producers.

2. Operation selection

In the Swine 2000 and 2006 surveys, an evaluation of the U.S. total inventory and

number of operations revealed that operations with 1 to 99 pigs accounted for 60.3

percent of pig operations in the 17 participating States but just 1.0 percent of total

pig inventory. Because this segment of the industry represented such small

percentage of the total U.S. inventory, it was ineligible for the study. Therefore,

larger operations representing 99.0 percent of the pig inventory were selected.

NASS chose a stratified random sample of 5,006 operations selected from their

list sampling frame comprised of independent and contract producers.

Stratification was based on State and herd size. Larger operations were selected

with a higher probability of being included in the sample in order to reduce

variability. Operations with 100 or more pigs were eligible for an on-site interview.

At the first interview, if operations had multiple production sites under different dayto-day management, a maximum of three sites were randomly selected (one with

breeding animals and two with weaned pigs).

3. Population inferences

Inferences cover the population of swine operations with 100 or more total pigs in

the 17 participating States. Appendix II shows that these States accounted for

93.6 percent of operations with 100 or more pigs and 94.2 percent of the U.S. pig

inventory on operations with 100 or more pigs (based upon the June 1, 2006,

inventory and 2006 number of operations). All respondent data were statistically

weighted to allow the sample to reflect the population from which it was selected.

The inverse of probability of selection for each operation was the initial selection

*Arkansas, Colorado, Iowa, Illinois, Indiana, Kansas, Michigan, Minnesota, Missouri, Nebraska,

North Carolina, Ohio, Oklahoma, Pennsylvania, South Dakota, Texas, and Wisconsin
Section II: Methodology

82 / Swine 2006

weight. This selection weight was adjusted for nonresponse within each region and

size group to allow for inferences back to the original population from which the

sample was selected. This weight was adjusted further for the number of separate

sites each operation had, relative to the number of sites that responded to the

survey.

1. General Swine Farm Report, July 17–September 15, 2006

NASS enumerators administered the General Swine Farm Report questionnaire in

person with each selected producer that agreed to participate in the study. The

interview took approximately 1 hour. For producers that had 100 or more head on

June 1, 2006, NASS enumerators asked permission for veterinary medical officers

(VMOs) to contact the producer and discuss additional phases of data collection.

1. Validation and estimation

Initial data entry and validation for the General Swine Farm Report (results

reported in Swine 2006, Part I) were performed in individual NASS State offices.

Data were entered into a SAS data set, followed by the execution of the edit and

validation program. NAHMS national staff performed additional data validation on

the entire data set after data from all States were combined.

The statistical estimation was done using SUDAAN. SUDAAN uses a Taylor

series expansion to estimate appropriate variances for the stratified/clustered,

weighted data.

C. Data Collection

E. Sample Evaluation

D. Data Analysis

1. General Swine Farm Report

The purpose of this section is to provide various performance measurement

parameters. Historically, the term “response rate” was used as a catch-all

parameter, but there are many ways to define and calculate response rates.

Therefore, the table to the right presents an evaluation based upon a number of

measurement parameters, which are defined with an “x” in those categories that

contribute to the measurement. Of the 5,006 operations selected, 3,071 (61.3

percent) provided usable inventory information. Note, the comparable weighted rate

was calculated at 65.7 percent usable operations. There were 2,079 operations

(41.5 percent) of the sample that provided “complete” information for the

questionnaire. About 9 of 10 operations (87.9 percent) were actually contacted for

the study.
Section II: Methodology

USDA APHIS VS / 83

1a. Operation level response

Survey complete operations were subdivided if multiple production sites existed.

A maximum of three sites were randomly selected. Overall, 2,230 site

questionnaires were completed for essentially the entire questionnaire, and 45.1

percent of the sites agreed to be contacted by APHIS for discussion about

participation in further phases of the study.

1b. Site level response

Evaluation 

Parameters 

Response Category Number 

Operations 

Percent 

Operations Contacts Usable 1/ 

Survey complete 2/ 2,079 41.5 x x 

No pigs on June 1, 2006 696 13.9 x x 

Out of business 296 5.9 x x 

Out of scope (prison and 

research farms, etc.) 13 0.3 

Refusal of GSFR 1,327 26.5 x 

Office hold (NASS elected 

not to contact) 315 6.3 

Inaccessible 280 5.6 

Total 5,006 100.0 4,398 3,071 

Percent of total operations 87.9 61.3 

Percent of total 

operations weighted 3/ 90.7 65.7 

1/ Useable operation – respondent provided answers to inventory questions for the operation (either 

zero or positive number on hand). 

2/ Survey complete operation – respondent provided answers to all or nearly all questions for at 

least one site. 

3/ Weighted response – the rate was calculated using the initial selection weights.

Response Category Number Sites1/ Percent Sites 

Survey complete and 

VMO consent 1,005 45.1 

Survey complete and 

refused VMO consent 1,225 54.9 

Total 2,230 100.0 

1/ There were 1,005 sites with survey complete and consent for the APHIS or VMO 

phase of the study which originated from 912 selected operations. Similarly, there were 

1,225 sites that completed the survey but declined the VMO phase, which came from 

the rest of the original 2,079 selected operations or 1,167 selected operations. 
 Appendix I: Sample Profile

84 / Swine 2006

Appendix I: Sample Profile

A. Responding Sites 1a. Total inventory

Size of Site 

(Total Inventory) Number Responding Sites 

Fewer than 2,000 1,157 

2,000 to 4,999 724 

5,000 or more 349 

Total 2,230 

1b. Sow inventory

Size of Site 

(Total Sows and Gilts) Number Responding Sites 

No sows and gilts 1,353 

Fewer than 250 468 

250 to 499 102 

500 or more 307 

Total 2,230 

2. Type of site

Type of Site Number Responding Sites 

Contract producer 1,027 

Independent—market own 

pigs 1,086 

Independent—market 

through cooperative 105 

Other 12 

Total 2,230 
Appendix I: Sample Profile

USDA APHIS VS / 85

3. Regions

Region Number Responding Sites 

North 499 

West Central 456 

East Central 888 

South 387 

Total 2,230 

4. Production phase

Production Phase Combination Number Responding Sites 

All four phases 502 

Gestation, farrowing, and nursery 81 

Nursery and grower/finisher 357* 

Gestation and farrowing 226* 

Nursery only 217* 

Grower/finisher only 809* 

Other combination 38 

Total 2,230 

*Revised December 2007 
Appendix II: U.S. Population and Operations

86 / Swine 2006

Appendix II: U.S. Swine Population and Operations

 Number Pigs 

(Thousand Head) 

Number Operations 

in 2006 

Region State 

All 

Operations 

Operations 

with 100 

or More 

Head1

All 

Operations 

Operations 

with 100 or 

More Head 

East 

Central Illinois 4,200 4,179 2,900 2,080 

 Indiana 3,200 3,171 2,800 1,500 

 Iowa 16,600 16,550 8,700 7,670 

 Ohio 1,620 1,539 4,000 1,300 

 Total 25,620 25,439 18,400 12,550 

North Michigan 980 965 2,100 560 

 Minnesota 6,800 6,766 4,800 3,600 

 Pennsylvania 1,100 1,067 3,100 800 

 Wisconsin 430 400 2,200 660 

 Total 9,310 9,198 12,200 5,620 

West 

Central Colorado 840 834 750 60 

 Kansas 1,840 1,827 1,400 540 

 Missouri 2,700 2,673 2,000 1,070 

 Nebraska 2,950 2,929 2,500 1,700 

South 

Dakota 1,470 1,455 1,100 730 

 Total 9,800 9,718 7,750 4,100 

South Arkansas 280 272 750 150 

North 

Carolina 9,600 9,590 2,300 1,510 

 Oklahoma 2,370 2,346 2,600 300 

 Texas 970 941 3,700 168 

 Total 13,220 13,149 9,350 2,128 

Total (17 States) 

57,950 

(93.9% of 

U.S.) 

57,504 

(94.2% of 

U.S.) 

47,700 

(72.8% of 

U.S.) 

24,398 

(93.6% of 

U.S.) 

Total U.S. (50 States) 61,687 61,070 65,540 26,058 

1

Derived from NASS publication Farm, Land in Farms, and Livestock Operations, February 2007 

Number of Pigs on June

1, 2006, and Number of

Operations in 2006
Appendix III: Swine 2006 Study Objectives and Related Outputs

USDA APHIS VS / 87

Appendix III: Study Objectives and Related Outputs

1. Describe swine management practices used during the gestation, farrowing,

nursery, and grower/finisher phases of production.

 • Part I: Reference of Swine Health and Management Practices in the

 United States, 2006, October 2007

 • Part II, Reference of Swine Health and Health Management in the United

 States, 2006, expected winter 2007

 • Part III, Reference of Swine Health, Productivity and General Management,

 expected winter 2007

 • Info sheets, expected fall and winter 2007

2. Determine the prevalence and risk factors for a variety of pathogens found in

nursery and grower/finisher pigs.

 • Part II, Reference of Swine Health and Health Management in the United

 States, 2006, expected winter 2007

 • Part III, Reference of Swine Health, Productivity and General Management,

 expected winter 2007

 • Info sheets, expected fall and winter 2007

3. Examine vaccination and antimicrobial use practices.

 • Part II, Reference of Swine Health and Health Management in the United

 States, expected winter 2007

4. Provide an overview of the changes in U.S. swine management and health from

1990 through 2006.

 • Part IV: Changes in the U.S. Pork Industry, 1990-2006, expected early 2008

 • Info sheets, expected early 2008