United States

Department of

Agriculture

Animal and

Plant Health

Inspection

Service

Veterinary

Services

National

Animal Health

Monitoring

System

November 2008

Swine 2006

Part IV: Changes in the U.S. Pork Industry,

1990-2006
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.aphis.usda.gov

#N520.1108

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

discrimination in all its programs and activities on the

basis of race, color, national origin, age, disability, and

where applicable, sex, marital status, familial status,

parental status, religion, sexual orientation, genetic

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provider and employer.
USDA APHIS VS / i

Acknowledgements

This report has been prepared from material received and analyzed by the U.S.

Department of Agriculture (USDA), Animal and Plant Health Inspection Service

(APHIS), Veterinary Services (VS).

The 1990 National Swine Survey, Swine ’95, Swine 2000, and Swine 2006

studies were cooperative efforts among State and Federal agricultural

statisticians, animal health officials, university researchers, and extension

personnel. We want to thank the National Agricultural Statistics Service (NASS)

enumerators, State and Federal veterinary medical officers (VMOs), and animal

health technicians (AHTs) who visited the sites and collected the data. Their hard

work and dedication to the National Animal Health Monitoring System (NAHMS)

are invaluable.

The roles of the producer, area veterinarian in charge (AVIC), NAHMS

coordinator, VMOs, AHTs, and NASS enumerators were critical in providing

quality data for the swine studies. Thanks also to the personnel at the Centers

for Epidemiology and Animal Health (CEAH) for their efforts in generating and

distributing the valuable reports.

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

efforts made the swine studies possible.

Larry M. Granger,

Director

Centers for Epidemiology and Animal Health
ii / Swine 2006

Suggested bibliographic citation for this report:

USDA. 2008. Part IV: Changes in the U.S. Pork Industry, 1990-2006.

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

#N520.1108

Contacts for further information:

Questions or comments on data analysis: Dr. Eric Bush (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 3

Section I: Demographic Changes in the U.S. and

World Pork Industries, 1850-2006 4

A. Historical Changes in the U.S. Pork Industry, 1850–2002 4

1. Total pig inventory 4

2. Number of swine sites and herd size 8

B. U.S. Pork Industry Changes 14

1. Inventories by State 14

C. World Pork Production Changes 18

1. Inventories by country 18

Section II: Health and Productivity Changes in the U.S. Pork Industry,

NAHMS Population Estimates—1990, 1995, 2000, and 2006 20

A. Farrowing Phase 20

1. Death loss and productivity 20

2. Cause of preweaned piglet deaths 21

3. Culling rate of sows 22

B. Nursery Phase 24

1. Death loss 24

2. Cause of nursery pig deaths 24

C. Grower/Finisher Phase 26

1. Death loss 26

2. Cause of grower/finisher pig deaths 26

D. Swine Diseases 27

1. Diseases reported in 12-month period 27

Section III: Management Changes in the U.S. Pork Industry,

NAHMS Population Estimates—1990, 1995, 2000, and 2006 31

A. Breeding Animals 31

1. Mating techniques 31

2. Preventive practices for sows and gilts 32

3. Preventive practices for boars 32
iv / Swine 2006

B. Suckling Piglets 33

1. Pig flow management 33

2. Waste management 34

3. Preventive practices 35

4. Average weaning age 35

C. Nursery Pigs 36

1. Pig flow management 36

2. Age leaving nursery 37

D. Grower/Finisher Pigs 38

1. Pig flow management 38

2. Market age 39

E. General Farm Management 40

1. Vaccination practices 40

2. Isolation or quarantine of new arrivals 41

3. Carcass disposal 42

4. Rodent control 44

5. Proximity to nearest swine farm or market 45

Section IV: Trends in Other National Data Bases 46

A. Slaughter Condemnation Rates in Federally Inspected

Slaughter Plants, 1996 Through 2006 46

1. Market pigs 46

2. Sows 48

B. Salmonella Serotypes 50

1. Most frequently identified serotypes 50

Appendix: Swine 2006 Study Objectives and Related Outputs 51
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 priorities for research and special studies, and detect emerging

problems.

Section I of this report presents demographic changes of the U.S. and world pork

industries from a historical perspective using data provided by the National

Agricultural Statistics Service (NASS), Census of Agriculture, and Foreign

Agricultural Service. Results of four NAHMS national studies in

Sections II and III provide an overview of change in U.S. swine management and

health from 1990 through 2006. Section IV provides information from other

national data bases.

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

Survey, provided a snapshot of swine health and management and served as a

baseline from which industry changes in animal health and management were

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

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

95 percent of the U.S. swine population. National estimates generated from this

study were reported in “Morbidity/Mortality and Health Management of Swine in

the United States” (November 1991).

The second NAHMS national swine study was implemented in 1995 via two

phases: Swine ’95 Baseline and Swine ’95: Grower/Finisher. Both phases were

conducted in the top 16 swine States, which represented 91 percent of the U.S.

swine population. The target population for the Baseline phase was producers

with at least one pig. Data were collected by two interviews of approximately

1,400 producers. National estimates generated from the Baseline phase were

reported in “Swine ’95 Part I: Reference of 1995 Swine Management Practices”

(October 1995). The Swine ’95: Grower/Finisher phase was conducted on-farm

via two interviews on sites with at least 300 market pigs. National estimates

generated from the Swine ’95: Grower/Finisher phase were reported in “Swine

‘95 Part II: Reference of 1995 Grower/Finisher Health and Management” (May

1996).

The third NAHMS national swine study, Swine 2000, provided both participants

and the industry with information on nearly 94 percent of the U.S. swine herd on

sites with 100 or more pigs. Data for “Swine 2000 Part I: Reference of Swine
Introduction

2 / Swine 2006

Health and Management in the United States, 2000” (August 2001) were

collected from 2,499 swine production sites from 2,328 operations. NASS

collaborated with Veterinary Services to select a producer sample statistically

designed to provide inferences to the Nation’s swine population on sites with 100

or more pigs. The study included 17 of the major pork-producing 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. NASS interviewers contacted producers from

June 1 through July 14, 2000. Respective results were published in “Swine 2000

Part II: Reference of Swine Health and Health Management in the United States,

2000” (March 2002) and “Swine 2000 Part III: Reference of Swine Health and

Environmental Management, 2000” (September 2002).

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

industry. The study’s 17 participating States accounted for 94 percent of swine

operations and inventory on operations with 100 or more pigs. A stratified

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 up to two times 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 followup visits between

December 4, 2006, and March 15, 2007. Results from the first data collection

period of this study were presented in “Swine 2006 Part I: Reference of Swine

Health and Management Practices in the United States, 2006” (October 2007).

Respective results were published in “Swine 2006 Part II: Reference of Swine

Health and Health Management Practices in the United States, 2006” (December

2007), and “Swine 2006 Part III: Reference of Swine Health, Productivity, and

General Management in the United States, 2006” (March 2008).

Reports and information sheets from all four NAHMS swine studies are available

at http://nahms.aphis.usda.gov

Interpretation of changes in estimates among four national studies conducted

between 1990 and 2006 are sometimes difficult. Major influences behind

differences in estimates may be due to differences in the composition of the

target population as described above. These differences are documented in

each summary table to aid in interpretation. Differences also may occur in the

factors being measured, e.g., changes in question wording, random variation,

and true secular time trends in the pork industry. These differences have been

documented to aid in interpretation.
USDA APHIS VS / 3

Introduction

Terms Used In

This Report

All in/all out: A management approach in which animals are moved as one

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.

NA: Not applicable.

Operation: The overall business and top-level management unit for a swine

rearing facility, which might consist of one or more sites (geographic locations).

An operation can encompass all production phases of swine rearing (i.e.,

gestation, farrowing, nursery, and grower/finisher) on one or more sites, each

devoted to a different production phase or combination of phases (see also

“Site”).

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

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

created 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. In general, when comparing point

estimates between categories, estimates with confidence levels that overlap are

not considered different. 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 (—).

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”).
Section I: Demorgraphic Changes in the Pork Industries—A. Historical Changes

4 / Swine 2006

A. Historical Changes

in the U.S. Pork

Industry, 1850–2002

Section I: Demographic Changes in the U.S. and World Pork

Industries, 1850-2006

1. Total pig inventory

The Census of Agriculture has collected hog and pig inventory numbers at 5-year

intervals since 1850. The table opposite shows inventory numbers at

approximately 10-year intervals (every other Census). The 2007 Census was

conducted in spring 2008 and will be published in spring 2009. The U.S. hog and

pig inventory had sporadic increases and declines from 1850 to 1880, with a

peak of 49 million head in 1880 and a low of 25 million head in 1870. A relatively

stable inventory predominated from 1890 through 1930, when the inventory

remained near 60 million head. By 1940, inventory had declined 40 percent,

followed by a similar percentage rebound by 1950. Hog and pig inventory peaked

in 1959 at nearly 68 million head. Estimates in subsequent years consistently

remained near 55 million head, increasing to 60.4 million head in 2002. The

number of hog sites declined dramatically starting in 1959. The 2002 Census

showed the number of sites at only 1.8 percent of those in 1900, while the

inventory number of head was nearly the same. As a result, the average herd

size increased from fewer than 20 head in the early and mid 1900s to 766 head

in 2002.
USDA APHIS VS / 5

Section I: Demographic Changes in the Pork Industries—A. Historical Changes

a. Changes in December 1 U.S. hog and pig inventory, 1850-2002:

 

Year* 

Total Inventory 

(1,000 Head) 

Sites 

Reporting 

Average 

Herd Size 

1850 30,354 NA NA 

1860 33,513 NA NA 

1870 25,135 NA NA 

1880 49,773 NA NA 

1890 57,427 NA NA 

1900 62,868 4,335,363 15 

1910 58,186 4,351,751 13 

1920 59,346 4,850,807 12 

1930 56,288 3,535,119 16 

1940 34,037 3,766,675 9 

1950 55,789 3,013,549 19 

1959 67,949 1,848,784 37 

1969 55,455 686,097 81 

1978 57,697 445,117 130 

1987 52,271 243,398 215 

1992 57,563 191,347 301 

1997 61,188 124,889 490 

2002 60,405 78,895 766 

*Census of Agriculture data. 1850-1950 includes all States except Alaska and Hawaii. 1959-2002 

includes all 50 States.
Section I: Demorgraphic Changes in the Pork Industries—A. Historical Changes

6 / Swine 2006

Each year, NASS surveys a random sample of producers to provide national

estimates of animal populations and food production. The table below reports

NASS demographics of the U.S. pork industry as published December 1 of each

year. From 1990 through 2006, hog and pig inventory estimates increased

14.8 percent. From 1990, year-to-year inventories varied slightly but increased

until 1998, followed by a decline until 2000. Breeding inventory made up

12.6 percent of total inventory in 1990 compared with 9.7 percent in 2006.

b. Changes in U.S. hog and pig and breeding inventories, December 1, 1990-

2006:*

Hogs and Pigs Breeding Inventory 

Year 

 

1,000 

Head 

Pct. 

Previous 

Year 

 

Pct. of 

1990 

 

Pct. of 

1995 

Pct. of 

2000 

 

1,000 

Head 

Pct. 

Previous 

Year 

 

Pct. of 

1990 

 

Pct. of 

1995 

Pct. of 

2000 

1990 54,416 101.2 100.0 -- -- 6,847 99.9 100.0 -- -- 

1991 57,649 105.9 105.9 -- -- 7,229 105.6 105.6 -- -- 

1992 58,202 101.0 107.0 -- -- 7,109 98.3 103.8 -- -- 

1993 57,940 99.5 106.5 -- -- 7,166 100.8 104.7 -- -- 

1994 59,738 103.1 109.8 -- -- 6,998 97.7 102.2 -- -- 

1995 58,201 97.4 107.0 100.0 -- 6,770 96.7 98.9 100.0 -- 

1996 56,124 96.4 103.1 96.4 -- 6,578 97.2 96.1 97.2 -- 

1997 61,158 109.0 112.4 105.1 -- 6,957 105.8 101.6 102.8 -- 

1998 62,204 101.7 114.3 106.9 -- 6,682 96.0 97.6 98.7 -- 

1999 59,335 95.4 109.0 101.9 -- 6,233 93.3 91.0 92.1 -- 

2000 59,110 99.6 108.6 101.6 100.0 6,267 100.5 91.5 92.6 100.0 

2001 59,722 101.0 109.8 102.6 101.0 6,201 98.9 90.6 91.6 98.9 

2002 59,554 99.7 109.4 102.3 100.8 6,058 97.7 88.5 89.5 96.7 

2003 60,444 101.5 111.1 103.9 102.3 6,009 99.2 87.8 88.8 95.9 

2004 60,975 100.9 112.1 104.8 103.2 5,969 99.3 87.2 88.2 95.2 

2005 61,449 100.8 112.9 105.6 104.0 6,011 100.7 87.8 88.8 95.9 

2006 62,490 101.7 114.8 107.4 105.7 6,087 101.3 88.9 89.9 97.1 

*Source: National Agricultural Statistics Service (NASS).
USDA APHIS VS / 7

Section I: Demographic Changes in the Pork Industries—A. Historical Changes
Section I: Demorgraphic Changes in the Pork Industries—A. Historical Changes

8 / Swine 2006

2. Number of swine sites and herd size

The number of U.S. swine sites has decreased steadily since 1990. In 2000, the

number of swine sites in the United States had decreased by two-thirds of the

1990 number, and in 2006 the number of swine sites had decreased to less than

one-fourth the number reported in 1990.

a. Changes in the number of U.S. swine sites, 1990-2006:*

 

Year Number 

Percent 

Previous 

Year 

Percent 

of 1990 

Percent 

of 1995 

Percent 

of 2000 

1990 268,140 89.1 100.0 -- -- 

1991 247,090 92.1 92.1 -- -- 

1992 240,150 97.2 89.6 -- -- 

1993 218,060 90.8 81.3 -- -- 

1994 196,030 89.9 73.1 -- -- 

1995 168,450 85.9 62.8 100.0 -- 

1996 142,380 84.5 53.1 84.5 -- 

1997 122,160 85.8 45.6 72.5 -- 

1998 113,590 93.0 42.4 67.4 -- 

1999 99,620 87.7 37.2 59.1 -- 

2000 87,470 87.8 32.6 51.9 100.0 

2001 81,220 92.9 30.3 48.2 92.9 

2002 76,250 93.9 28.4 45.3 87.2 

2003 73,720 96.7 27.5 43.8 84.3 

2004 69,500 94.3 25.9 41.3 79.5 

2005 67,280 96.8 25.1 39.9 76.9 

2006 65,940 98.0 24.6 39.1 75.4 

*Source: NASS.
USDA APHIS VS / 9

Section I: Demographic Changes in the Pork Industries—A. Historical Changes
Section I: Demorgraphic Changes in the Pork Industries—A. Historical Changes

10 / Swine 2006

Small herds still represent the majority of U.S. pig sites. However, the number of

sites with fewer than 100 head declined steadily as a percentage of all sites from

1990 through 1999, but then began a small return to previous levels so that in

2006 the percentage of these smaller producers was at 1993 levels. The

percentage of sites with 100 to 499 head and with 500 to 999 head has

decreased since 1998. The percentage of sites with a total inventory of 2,000 or

more head consistently increased from 2.1 percent in 1993 to 11.7 percent in

2006.

b. Percentage of U.S. pig sites by herd size, 1990-2006:1

Percent Sites 

Herd Size 

 

Year 1-99 Head 

100-499 

Head 

500-999 

Head 

1,000- 

1,999 Head 

2,000- 

4,999 Head 

5,000 or 

More Head 

 

Total 

1990 63.9 25.0 7.1 4.0 2 2 100.0 

1991 61.4 26.4 7.8 4.4 2 2 100.0 

1992 60.2 26.5 8.1 5.2 2 2 100.0 

1993 60.1 25.8 8.4 3.6 1.6 0.5 100.0 

1994 58.6 25.9 8.8 4.2 1.9 0.6 100.0 

1995 57.4 26.2 9.0 4.4 2.2 0.8 100.0 

1996 57.5 25.0 9.1 4.8 2.5 1.1 100.0 

1997 56.9 23.0 9.5 5.5 3.6 1.5 100.0 

1998 54.4 23.8 9.9 6.0 4.2 1.7 100.0 

1999 54.2 22.8 9.2 6.6 5.1 2.1 100.0 

2000 57.3 19.3 8.7 6.7 5.6 2.4 100.0 

2001 58.8 17.6 8.3 6.5 6.1 2.7 100.0 

2002 59.8 16.1 8.2 6.6 6.3 3.0 100.0 

2003 60.3 15.7 7.7 6.6 6.6 3.1 100.0 

2004 60.6 14.9 7.4 6.4 7.4 3.3 100.0 

2005 60.3 15.0 7.1 6.3 7.8 3.5 100.0 

2006 60.5 14.6 6.8 6.4 8.0 3.7 100.0 

1

Source: NASS. 

2

Only estimates of 1,000 or more head were available in 1990–92.
USDA APHIS VS / 11

Section I: Demographic Changes in the Pork Industries—A. Historical Changes

The percentage of pig inventory on sites with 1 to 1,999 head has decreased

steadily since 1990. The percentage of pig inventory on sites with 2,000 or more

head has increased by a factor of 2.4 since 1993.

c. Percentage of U.S. total hog and pig inventory by herd size, 1990-2006:1

Percent Total Hog and Pig Inventory 

Herd Size 

 

Year 

1-99 

Head 

100-499 

Head 

500-999 

Head 

1,000- 

1,999 Head 

2,000- 

4,999 Head 

5,000 or 

More Head Total 

1990 6.4 28.6 23.8 41.2 2 2

 100.0 

1991 5.5 27.2 23.4 43.9 2 2 100.0 

1992 5.3 25.3 22.0 47.4 2 2 100.0 

1993 5.0 22.5 21.5 17.5 15.5 18.0 100.0 

1994 4.0 20.5 19.5 18.0 17.0 21.0 100.0 

1995 3.5 18.0 17.0 17.0 17.0 27.5 100.0 

1996 3.0 15.0 15.0 16.0 17.0 34.0 100.0 

1997 2.0 11.0 12.0 14.5 20.5 40.0 100.0 

1998 2.0 9.5 11.0 14.0 21.5 42.0 100.0 

1999 1.5 8.0 9.0 13.0 22.5 46.0 100.0 

2000 1.0 6.5 8.0 12.5 22.0 50.0 100.0 

2001 1.0 5.5 7.5 12.0 23.0 51.0 100.0 

2002 1.0 5.0 6.5 12.0 22.5 53.0 100.0 

2003 1.0 4.5 6.5 11.0 24.0 53.0 100.0 

2004 1.0 4.0 6.0 10.0 26.0 53.0 100.0 

2005 1.0 4.0 6.0 10.0 26.0 53.0 100.0 

2006 1.0 4.0 5.0 10.0 26.0 54.0 100.0 

1

Source: NASS. 

2

Only estimates of 1,000 or more head were available in 1990–92.
Section I: Demorgraphic Changes in the Pork Industries—A. Historical Changes

12 / Swine 2006
USDA APHIS VS / 13

Section I: Demographic Changes in the Pork Industries—A. Historical Changes

Except in 1990, 1993, and 1998, fewer pigs were weaned per litter in December–

February than during the other quarters. In general, the number of pigs weaned

per litter increased each quarter since 1990.

d. Changes in pigs weaned per litter, per quarter, 1990-2006:1

 

Year 

DecFeb2

Pct. 

1995 

Pct. 

2000 

MarMay Pct. 

1995 

Pct. 

2000 

JunAug Pct. 

1995 

Pct. 

2000 

SepNov Pct. 

1995 

Pct. 

2000 

1990 7.83 -- -- 7.94 -- -- 7.90 -- -- 7.82 -- -- 

1991 7.87 -- -- 7.96 -- -- 7.89 -- -- 7.89 -- -- 

1992 8.04 -- -- 8.08 -- -- 8.14 -- -- 8.05 -- -- 

1993 8.14 -- -- 8.13 -- -- 8.09 -- -- 8.05 -- -- 

1994 8.10 -- -- 8.26 -- -- 8.21 -- -- 8.16 -- -- 

1995 8.24 100.0 -- 8.32 100.0 -- 8.34 100.0 -- 8.35 100.0 -- 

1996 8.43 102.3 -- 8.48 101.9 -- 8.55 102.5 -- 8.54 102.3 -- 

1997 8.63 104.7 -- 8.67 104.2 -- 8.72 104.6 -- 8.67 103.8 -- 

1998 8.70 105.6 -- 8.75 105.2 -- 8.72 104.6 -- 8.66 103.7 -- 

1999 8.73 105.9 -- 8.80 105.8 -- 8.86 106.2 -- 8.78 105.1 -- 

2000 8.76 106.3 100.0 8.86 106.5 100.0 8.84 106.0 100.0 8.85 106.0 100.0 

2001 8.72 105.8 99.5 8.89 106.9 100.3 8.89 106.6 100.6 8.85 106.0 100.0 

2002 8.77 106.4 100.1 8.84 106.3 99.8 8.92 107.0 100.9 8.86 106.1 100.1 

2003 8.81 106.9 100.6 8.88 106.7 100.2 8.90 106.7 100.7 8.93 106.9 100.9 

2004 8.85 107.4 101.0 8.93 107.3 100.8 9.01 108.0 101.9 8.96 107.3 101.2 

2005 8.94 108.5 102.1 9.02 108.4 101.8 9.06 108.6 102.5 9.03 108.1 102.0 

2006 9.03 109.6 103.1 9.08 109.1 102.5 9.11 109.2 103.1 9.11 109.1 102.9 

1 Source: NASS. Ratio of expected number of pigs weaned to sows/gilts farrowed. 

2

December preceding year.
Section I: Demographic Changes in the Pork Industries—B. U.S. Pork Industry Changes

14 / Swine 2006

B. U.S. Pork Industry

Changes

1. Inventories by State

The following table describes U.S. pork industry changes by State for 1990,

1995, 2000, and 2006. The pig inventories and number of sites are by State and

based on USDA-NASS data. The table also identifies which States participated in

the four NAHMS national swine studies. December 1, 2006, inventory levels

were considerably above December 1, 1990, levels, especially in the three States

with the most pigs—Iowa, North Carolina, and Minnesota—as well as many of

the Western States. Declining inventories were shown in the traditional hograising States of Illinois, Indiana, Ohio, South Dakota, and Wisconsin.

a. Changes in number of pigs by State (NASS):

Total Pigs (1,000 Head)

State 

Dec. 1, 

1990 

Dec. 1, 

1995 

Dec. 1, 

2000 

Dec. 1, 

2006 

2006 Pct. 

of 1990 

2006 Pct. 

of 1995 

2006 Pct. 

of 2000 

Alabama1

 355 230 165 165 46.5 71.7 100.0 

Alaska 1.2 2 0.8 0.9 75.0 45.0 112.5 

Arizona 110 125 9 148 134.5 118.4 1,644.4 

Arkansas3 4 760 790 685 260 34.2 32.9 38.0 

California1 195 240 150 145 74.4 60.4 96.7 

Colorado1 3 4 300 580 840 840 280.0 144.8 100.0 

Connecticut 6.9 5 4 3.6 52.2 72.0 90.0 

Delaware 31 33 20 10.5 33.9 31.8 52.5 

Florida 130 85 40 20 15.4 23.5 50.0 

Georgia1 2 1,100 700 380 245 22.3 35.0 64.5 

Hawaii 36 34 26 16 44.4 47.1 61.5 

Idaho 60 45 24 25 41.7 55.6 104.2 

Illinois1 2 3 4 5,700 4,800 4,150 4,200 73.7 87.5 101.2 

Indiana1 2 3 4 4,400 4,000 3,350 3,350 76.1 83.8 100.0 

Iowa1 2 3 4 13,800 13,500 15,100 17,300 125.4 128.1 114.6 

Kansas2 3 4 1,500 1,300 1,520 1,840 122.7 141.5 121.1 

Kentucky 2 920 800 430 310 33.7 38.8 72.1 

Louisiana 50 55 29 14 28.0 25.5 48.3 

Maine 8 7 6 4.8 60.0 68.6 80.0 

Maryland1 162 80 40 33 20.4 41.3 82.5 

Massachusetts 33 21 21 13 39.4 61.9 61.9 

Michigan1 2 3 4 1,250 1,100 950 1,000 80.0 90.9 105.3 

Minnesota1 2 3 4 4,500 4,950 5,800 6,900 153.3 139.4 119.0 

Mississippi 149 225 315 335 224.8 148.9 106.3 

Missouri2 3 4 2,800 3,550 2,900 2,800 100.0 78.9 96.6 

Montana 185 180 155 180 97.3 100.0 116.1 

Nebraska1 2 3 4 4,300 4,050 3,050 3,050 70.9 75.3 100.0 

Nevada 14 7 7.5 3.5 25.0 50.0 46.7 

New Hampshire 6 3 4 2.8 46.7 93.3 70.0 

New Jersey 25 34 14 9 36.0 26.5 64.3 

New Mexico 27 5 3 2 7.4 40.0 66.7 

1

Participated in 1990 National Swine Survey (total of 18 States). 

2

Participated in Swine ’95 study (total of 16 States). 

3

Participated in Swine 2000 study (total of 17 States). 

4

Participated in Swine 2006 study (total of 17 States). 
USDA APHIS VS / 15

Section I: Demographic Changes in the Pork Industries—B. U.S. Pork Industry Changes

a. Changes in number of pigs by State (NASS) continued:

Total Pigs (1,000 Head)

State 

Dec. 1, 

1990 

Dec. 1, 

1995 

Dec. 1, 

2000 

Dec. 1, 

2006 

2006 Pct. 

of 1990 

2006 Pct. 

of 1995 

2006 Pct. 

of 2000 

New York 103 66 80 98 95.1 148.5 122.5 

North Carolina1 2 3 4 2,800 8,200 9,300 9,500 339.3 115.9 102.2 

North Dakota 265 280 185 169 63.8 60.4 91.4 

Ohio1 2 3 4 2,000 1,800 1,490 1,690 84.5 93.9 113.4 

Oklahoma3 4 215 1,000 2,310 2,330 1,083.7 233.0 100.9 

Oregon1 80 45 32 25 31.3 55.6 78.1 

Pennsylvania1 2 3 4 920 1,000 1,030 1,080 117.4 108.0 104.9 

Rhode Island 5.3 3.0 2.5 2.1 39.6 70.0 84.0 

South Carolina 400 350 290 295 73.8 84.3 101.7 

South Dakota2 3 4 1,770 1,450 1,320 1,270 71.8 87.6 96.2 

Tennessee1 2 620 500 230 220 35.5 44.0 95.7 

Texas3 4 550 500 920 940 170.9 188.0 102.2 

Utah 33 62 550 680 2,060.6 1,096.8 123.6 

Vermont 5 2.5 2.5 2.5 50.0 100.0 100.0 

Virginia1 430 380 425 365 84.9 96.1 85.9 

Washington 56 51 27 36 64.3 70.6 133.3 

W. Virginia 30 22.0 10 11 36.7 50.0 110.0 

Wisconsin1 2 3 4 1,200 880 610 450 37.5 51.1 73.8 

Wyoming 20 73 108 100 500.0 137.0 92.6 

U.S. 54,416 58,201 59,110 62,490 114.8 107.4 105.7 

1

Participated in 1990 National Swine Survey (total of 18 States). 

2

Participated in Swine ’95 study (total of 16 States). 

3

Participated in Swine 2000 study (total of 17 States). 

4

Participated in Swine 2006 study (total of 17 States). 
Section I: Demographic Changes in the Pork Industries—B. U.S. Pork Industry Changes

16 / Swine 2006

b. Changes in number of swine sites (NASS):

Number of Sites 

State 1990 1995 2000 2006 

2006 Pct. 

of 1990 

2006 Pct. 

of 1995 

2006 Pct. 

of 2000 

Alabama1

 4,500 2,100 700 450 10.0 21.4 64.3 

Alaska 40 50 50 50 125.0 100.0 100.0 

Arizona 400 310 230 150 37.5 48.4 65.2 

Arkansas3 4 3,100 1,790 1,100 750 24.2 41.9 68.2 

California1 4,000 3,200 1,000 800 20.0 25.0 80.0 

Colorado1 3 4 2,000 1,400 900 800 40.0 57.1 88.9 

Connecticut 450 400 180 250 55.6 62.5 138.9 

Delaware 420 200 100 70 16.7 35.0 70.0 

Florida 5,000 3,200 1,400 1,100 22.0 34.4 78.6 

Georgia1 2 8,000 3,000 1,200 700 8.8 23.3 58.3 

Hawaii 500 300 230 230 46.0 76.7 100.0 

Idaho 2,000 1,100 400 650 32.5 59.1 162.5 

Illinois1 2 3 4 15,300 9,600 5,100 2,900 19.0 30.2 56.9 

Indiana1 2 3 4 13,000 9,000 4,400 2,800 21.5 31.1 63.6 

Iowa1 2 3 4 35,000 25,000 12,300 8,700 24.9 34.8 70.7 

Kansas2 3 4 6,000 3,800 1,600 1,400 23.3 36.8 87.5 

Kentucky 2 6,500 3,800 1,300 900 13.8 23.7 69.2 

Louisiana 2,500 1,200 650 600 24.0 50.0 92.3 

Maine 1,600 1,300 300 370 23.1 28.5 123.3 

Maryland1 1,400 800 430 400 28.6 50.0 93.0 

Massachusetts 850 700 300 300 35.3 42.9 100.0 

Michigan1 2 3 4 5,500 4,700 2,500 2,100 38.2 44.7 84.0 

Minnesota1 2 3 4 15,000 10,500 7,300 4,800 32.0 45.7 65.8 

Mississippi 6,000 2,300 1,500 1,000 16.7 43.5 66.7 

Missouri2 3 4 16,000 8,500 3,600 2,000 12.5 23.5 55.6 

Montana 1,500 900 650 500 33.3 55.6 76.9 

Nebraska1 2 3 4 12,500 10,000 4,000 2,500 20.0 25.0 62.5 

Nevada 140 140 100 110 78.6 78.6 110.0 

New Hampshire 750 400 250 300 40.0 75.0 120.0 

New Jersey 700 650 400 300 42.9 46.2 75.0 

New Mexico 900 500 400 350 38.9 70.0 87.5 

1

Participated in 1990 National Swine Survey (total of 18 States). 

2

Participated in Swine ’95 study (total of 16 States). 

3

Participated in Swine 2000 study (total of 17 States). 

4

Participated in Swine 2006 study (total of 17 States). 
USDA APHIS VS / 17

Section I: Demographic Changes in the Pork Industries—B. U.S. Pork Industry Changes

b. Changes in number of swine sites (NASS) continued:

Number of Sites 

State 1990 1995 2000 2006 

2006 Pct. 

of 1990 

2006 Pct. 

of 1995 

2006 Pct. 

of 2000 

New York 2,900 1,800 1,100 1,200 41.4 66.7 109.1 

North Carolina1 2 3 4 10,000 6,000 3,600 2,300 23.0 38.3 63.9 

North Dakota 2,100 1,500 700 430 20.5 28.7 61.4 

Ohio1 2 3 4 13,600 8,500 5,200 4,000 29.4 47.1 76.9 

Oklahoma3 4 5,200 3,400 2,700 2,600 50.0 76.5 96.3 

Oregon1 2,400 1,600 1,000 1,100 45.8 68.8 110.0 

Pennsylvania1 2 3 4 7,500 4,600 3,300 3,200 42.7 69.6 97.0 

Rhode Island 90 60 50 50 55.6 83.3 100.0 

South Carolina 5,500 2,000 900 1,100 20.0 55.0 122.2 

South Dakota2 3 4 7,700 5,400 1,900 1,100 14.3 20.4 57.9 

Tennessee1 2 8,500 4,000 1,500 1,100 12.9 27.5 73.3 

Texas3 4 11,000 7,000 4,300 3,700 33.6 52.9 86.0 

Utah 900 700 500 450 50.0 64.3 90.0 

Vermont 1,100 400 250 280 25.5 70.0 112.0 

Virginia1 3,500 1,800 1,200 850 24.3 47.2 70.8 

Washington 2,500 1,400 800 900 36.0 64.3 112.5 

W. Virginia 2,300 1,400 1,000 900 39.1 64.3 90.0 

Wisconsin1 2 3 4 9,400 5,700 2,700 2,200 23.4 38.6 81.5 

Wyoming 400 350 200 150 37.5 42.9 75.0 

U.S. 268,140 168,450 87,470 65,940 24.6 39.1 75.4 

1

Participated in 1990 National Swine Survey (total of 18 States). 

2

Participated in Swine ’95 study (total of 16 States). 

3

Participated in Swine 2000 study (total of 17 States). 

4

Participated in Swine 2006 study (total of 17 States). 
Section I: Demographic Changes in the Pork Industries—C. World Pork Production Changes

18 / Swine 2006

C. World Pork

Production Changes

1. Inventories by country

a. Changes in pig inventories in selected countries:*

 Inventory (1,000 Head)

Continent/Country 

Jan. 1, 

1991 

Jan. 1, 

1996 

Jan. 1, 

2001 

Jan. 1, 

2006 

Canada 10,172 11,588 13,576 15,110 

Mexico 8,593 11,100 10,649 10,125 

United 

States 54,416 58,201 59,110 62,490 

North 

America 

 Subtotal 73,181 80,889 83,335 87,725 

South Brazil 32,550 32,068 32,440 32,938 

America Subtotal 32,550 32,068 32,440 32,938 

116,6681

 115,9591 158,7652 157,3642 European 

Union Subtotal 116,668 115,959 158,765 157,364 

Bulgaria 4,187 2,140 NA NA 

Czech 

Republic 4,630 4,024 NA NA 

Hungary 8,000 5,032 NA NA 

Poland 19,739 20,343 NA NA 

Romania 12,003 7,960 NA NA 

Eastern 

Europe 

 Subtotal 48,559 39,499 NA NA 

Russian 

Federation 38,314 22,630 15,780 16,550 

Ukraine 19,427 13,144 7,652 7,052 

Former 

Soviet Union 

 Subtotal 57,741 35,774 23,432 23,602 

China, 

Peoples 

Republic of 362,408 441,692 446,815 503,348 

Japan 11,355 9,900 9,788 9,620 

Korea, 

Republic of 4,528 6,461 7,350 8,098 

Philippines 8,007 9,023 11,715 13,041 

Taiwan 8,565 10,510 7,495 7,172 

Asia 

 Subtotal 394,863 477,586 483,163 541,279 

Australia 2,530 2,600 2,748 2,490 Oceania 

 Subtotal 2,530 2,600 2,748 2,490 

Other NA NA NA 29,800 

Total 726,092 784,375 783,883 875,198 

*Statistical data provided by Foreign Agriculture Service (FAS). 

1

European Union–15 includes Austria, Belgium, Denmark, Finland, France, Germany, Greece, 

Ireland, Italy, Luxembourg, Netherlands, Portugal, Spain, Sweden, and U.K. 

2

European Union–27 includes Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, 

Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, 

Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, and U.K.
USDA APHIS VS / 19

Section I: Demographic Changes in the Pork Industries—C. World Pork Production Changes

b. Changes in pig inventory percentages in selected countries:*

Continent/Country 

2001 as 

Pct. of 

1991 

2001 as 

Pct. of 

1996 

2006 as 

Pct. of 

1991 

2006 as 

Pct. of 

1996 

2006 as 

Pct. of 

2001 

Canada 133.5 117.2 148.5 130.4 111.3 

Mexico 123.9 95.9 117.8 91.2 95.1 

United States 108.6 101.6 114.8 107.4 105.7 

North 

America 

 Subtotal 113.9 103.0 118.5 107.2 104.0 

South Brazil 136.1 136.9 134.9 135.7 99.1 

America Subtotal 136.1 136.9 134.9 135.7 99.1 

European 

Union NC NC NC NC 99.1 

Bulgaria 

Czech 

Republic 

Hungary 

Poland 

Romania 

Eastern 

Europe 

 Subtotal 

Data were not available for all 

countries for all years. 

Russian 

Federation 41.2 69.7 43.2 73.1 104.9 

Ukraine 39.4 58.2 36.3 53.7 92.2 

Former 

Soviet Union 

 Subtotal 40.6 65.5 40.9 66.0 100.7 

China, 

Peoples 

Republic of 123.3 101.2 138.9 114.0 112.7 

Japan 86.2 98.9 84.7 97.2 98.3 

Korea, 

Republic of 162.3 113.8 178.8 125.3 110.2 

Philippines 146.3 129.8 162.9 144.5 111.3 

Taiwan 87.5 71.3 83.7 68.2 95.7 

Asia 

 Subtotal 122.4 101.2 137.1 113.3 112.0 

Australia 108.6 105.7 98.4 95.8 90.6 Oceania 

 Subtotal 108.6 105.7 98.4 95.8 90.6 

Other NC NC NC NC NC 

Total NC NC NC NC 111.6 

*Statistical data provided by Foreign Agriculture Service (FAS). 

NC = Not comparable. 
Section II: Health and Productivity Changes in the U.S. Pork Industry—A. Farrowing Phase

20 / Swine 2006

Section II: Health and Productivity Changes in the U.S. Pork Industry,

NAHMS Population Estimates—1990, 1995, 2000, and 2006

A. Farrowing Phase NOTE: This section contains no information by herd size or region.

However, herd size and regional information is available in individual

reports for the various study years at: http://nahms.aphis.usda.gov.

Animal- and litter-level estimates for Section II are for sites with

1 or more pigs (1992, 1995) and 100 or more pigs (2000, 2006). Site-level

estimates are for sites with 100 or more pigs.

1. Death loss and productivity1

Since 1990, the number of pigs born alive per litter has increased by 1.33 piglets

per litter, and total born per litter has increased by 1.50 piglets per litter. The

number of stillbirths and mummies per litter was similar in 1990 and 2000 but

steadily increased from 1995 to 2006 by approximately 0.2 piglets each survey

year. Stillbirths and mummies as a percentage of total born per litter also

increased steadily from 1995 to 2006. The number of preweaning deaths per

litter was similar in 1990 and 2000 but increased by approximately 0.3 piglets

between 1990 and 2006. The number of pigs weaned per litter increased by

about one pig per litter from 1990 to 2006.

Per litter productivity:

1990 National 

Swine Survey 2 

Swine ‘95 

(12/94-11/95) 

Swine 2000 

(12/99-11/00) 

Swine 2006 

(12/05-11/06) 

 

Measure No. 

Std. 

Error Pct. No. 

Std. 

Error Pct. No. 

Std. 

Error Pct. No. 

Std. 

Error Pct. 

Stillbirths 

and mummies 

per litter 0.87 NA 8.41 0.65 (0.02) 6.49 0.81 (0.04) 7.53 1.04 (0.07) 8.76 

Born alive 

per litter 9.47 (0.04) 91.59 9.37 (0.07) 93.51 9.94 (0.06) 92.47 10.80 (0.13) 91.24 

Total born 

per litter 10.34 (0.04) 100.00 10.02 (0.07) 100.00 10.75 (0.08) 100.00 11.84 (0.13) 100.00 

Preweaning 

deaths per litter 1.10 (0.04) 11.62 0.88 (0.03) 9.39 1.17 (0.03) 11.77 1.42 (0.08) 13.15 

Weaned 

per litter 8.37 (0.05) 88.38 8.49 (0.06) 90.61 8.77 (0.06) 88.23 9.38 (0.14) 86.85 

Total born 

alive per litter 9.47 (0.04) 100.00 9.37 (0.06) 100.00 9.94 (0.06) 100.00 10.80 (0.13) 100.00 1 Per litter productivity was calculated as a ratio of a weighted sum of events (such as number born) across all sites (numerator) to 

the weighted sum of farrowings across all sites (denominator). 

2

Prospective monitoring via diary cards for a 3-month period per site with sites enrolled at different times covering the entire year. 
USDA APHIS VS / 21

Section II: Health and Productivity Changes in the U.S. Pork Industry—A. Farrowing Phase

2. Cause of preweaned piglet deaths

In all four studies, producers identified piglets lain on as the leading cause of

preweaning deaths.

Percentage of preweaning deaths* by producer-identified cause:

1990 National 

Swine Survey 

Swine ’95 

(12/94-11/95) 

Swine 2000 

(12/99-11/00) 

Swine 2006 

(12/05-11/06) 

Question 

Variation 

Deaths due to 

attributed first 

and second 

leading causes Deaths due to all causes 

 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Scours 23.9 (1.5) 15.1 (0.2) 11.0 (1.7) 11.5 (3.5) 

Lain on 40.4 (1.8) 48.7 (3.4) 50.8 (2.1) 45.6 (5.8) 

Starvation 20.4 (1.1) 20.5 (2.7) 18.6 (1.9) 22.8 (6.5) 

Respiratory NA NA 2.2 (0.4) 5.9 (3.7) 

Other known 

problem 9.0 (1.8) 6.6 (1.0) 8.2 (1.0) 7.5 (2.5) 

Unknown 

problem 6.3 (1.5) 9.1 (1.3) 9.2 (1.0) 6.7 (1.9) 

Total 100.0 100.0 100.0 100.0 

*The question variation in 1990 precipitated the change in denominator from percentage of first and second 

leading causes to percentage of deaths due to all causes, which decreased estimates for the most common 

causes of death and increased estimates for the less frequent causes. 
Section II: Health and Productivity Changes in the U.S. Pork Industry—A. Farrowing Phase

22 / Swine 2006

3. Culling rate of sows

Cull rates ranged from a low of 37.7 percent in 2000 to a high of 48.8 percent in

2006. Note: The reasons-for-culling categories differed between the 1995, 2000,

and 2006 studies; in 1995, disease was a specific reason for culling, whereas in

2000 and 2006 reproductive failure replaced the disease category. In 2006, injury

was a new category.

a. Breeding-age females culled over a 12-month period as a percentage of sow

and gilt inventory:

1990 National 

Swine Survey1 

Swine ’95 

(12/94-11/95) 

Swine 20002

(12/99-11/00) 

Swine 20062

(12/05-11/06) 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

43.5 NA 41.2 (1.7) 37.7 (2.5) 48.8 (7.5) 

1

Prospective monitoring via diary cards for a 3-month period per site with sites enrolled at different

times covering the entire year. 

2

Excludes gilts intended for breeding but not yet in the breeding herd. 

.
USDA APHIS VS / 23

Section II: Health and Productivity Changes in the U.S. Pork Industry—A. Farrowing Phase

b. Percentage of culled breeding-age females from December 1 through May 31,

by reason culled:

Swine ‘95 Swine 2000 Swine 2006 

 

Reason Culled 

Percent 

Females 

Std. 

Error 

Percent 

Females 

Std. 

Error 

Percent 

Females 

Std. 

Error 

Age 40.7 (2.1) 41.9 (1.8) 36.6 (2.6) 

Lameness 9.2 (0.7) 16.0 (1.2) 15.2 (2.3) 

Performance* 33.0 (2.2) 12.0 (0.7) 13.0 (1.1) 

Disease 2.5 (0.7) NA NA 

Reproductive failure NA 21.3 (1.3) 26.3 (1.9) 

Injury NA NA 4.0 (0.6) 

Other 14.6 (2.4) 8.8 (1.6) 4.9 (0.8) 

Total 100.0 100.0 100.0 

*Small litter size, high preweaning mortality, or low birth weight. 
Section II: Health and Productivity Changes in the U.S. Pork Industry—B. Nursery Phase

24 / Swine 2006

B. Nursery Phase 1. Death loss

The nursery mortality rate was less than 4 percent in all four study years. Note:

The definition of a nursery varied between studies.

Percentage of nursery pigs that died during the nursery phase:

2. Cause of nursery pig deaths

Nearly half the nursery pig deaths in 2006 (44.2 percent) were attributed to

respiratory disease.

Percentage of nursery pig deaths* by producer-identified cause:

1990 National 

Swine Survey1 2

Swine ’953

(12/94-5/95) 

Swine 20003

(12/99-5/00) 

Swine 20064

(12/05-5/06) 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

2.4 (0.1) 2.3 (0.1) 2.6 (0.1) 2.9 (0.1) 

1

Question variation: nursery unit, all weaned pigs less than 40 lb. 

2

 Based on questionnaire for a 3-month period prior to the interview; farms enrolled at different times 

covering the entire year. 

3

Question variation: nursery unit, physically separate unit. 

4

Question variation: nursery defined as generally weaning to 60 lb. 

1990 National 

Swine Survey 

Swine ’95 

(12/94-5/95) 

Swine 2000 

(12/99-5/00) 

Swine 2006 

(12/05-5/06) 

Question 

Variation 

Deaths due to 

attributed first 

and second 

leading causes Percent deaths due to all causes 

 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Scours 25.1 (2.7) 15.0 (1.7) 12.6 (1.2) 12.5 (1.1) 

Starvation 8.7 (1.2) 12.4 (1.8) 13.3 (1.1) 9.8 (0.9) 

Respiratory 

problems 23.9 (2.5) 32.4 (2.5) 28.9 (1.7) 44.2 (2.3) 

CNS/meningitis NA NA NA 18.7 (1.9) 

Other identified 

problem 24.4 (3.6) 18.2 (2.8) 24.5 (3.4) 4.1 (0.8) 

Unknown 

problem 17.9 (1.7) 22.0 (2.5) 20.7 (3.5) 10.7 (1.1) 

Total 100.0 100.0 100.0 100.0 

*The question variation in 1990 precipitated the change in denominator from percentage of first and second 

leading causes to percentage of deaths due to all causes, which decreased estimates for the most common 

causes of death and increased estimates for the less frequent causes. 
USDA APHIS VS / 25

Section II: Health and Productivity Changes in the U.S. Pork Industry—B. Nursery Phase
Section II: Health and Productivity Changes in the U.S. Pork Industry—C. Grower/Finisher Phase

26 / Swine 2006

C. Grower/Finisher

Phase

1. Death loss

The mortality rate for grower/finisher pigs in 2006 was more than twice that of

1990.

Percentage of grower/finisher pigs that died during the grower/finisher phase:

2. Cause of grower/finisher pig deaths

Similar to nursery pigs, a higher percentage of grower/finisher pig deaths were

due to respiratory disease in 2006 than in 1990, 1995, and 2000. The

percentages of deaths due to lameness, trauma, and stress were lower in 2006

than in 2000.

Percentage of grower/finisher deaths* by producer-identified cause:

1990 National 

Swine Survey 

Swine ’95 

(12/94-5/95) 

Swine 2000 

(12/99-5/00) 

Swine 2006 

(12/05-5/06) 

Question 

Variation 

Deaths due to 

attributed first 

and second 

leading causes Percent of deaths due to all causes 

 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Scours 1.9 (0.4) 7.5 (1.2) 5.3 (2.0) 6.7 (0.6) 

Lameness 7.9 (0.8) 8.0 (0.7) 8.4 (0.8) 5.4 (0.3) 

Trauma 8.6 (1.3) 6.7 (0.6) 8.0 (0.5) 4.9 (0.4) 

Respiratory 

problem 47.9 (2.6) 40.2 (2.1) 39.1 (2.0) 61.1 (2.3) 

Stress NA NA 6.7 (0.6) 3.2 (0.3) 

Other identified 

problem 14.9 (1.9) 17.2 (1.9) 14.2 (1.5) 8.0 (3.4) 

Unknown 

problem 18.8 (1.9) 20.4 (1.7) 18.3 (1.4) 10.7 (1.0) 

Total 100.0 100.0 100.0 100.0 

*The question variation in 1990 precipitated the change in denominator from percentage of first and second 

leading causes to percentage of deaths due to all causes, which decreased estimates for the most common 

causes of death and increased estimates for the less frequent causes. 

1990 National 

Swine Survey 

(12 months) 

Swine ’95 

(12/94-5/95) 

Swine 2000 

(12/99-5/00) 

Swine 2006 

(12/05-5/06) 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

1.8 (0.1) 2.1 (0.1) 2.9 (0.1) 3.9 (0.2) 
USDA APHIS VS / 27

Section II: Health and Productivity Changes in the U.S. Pork Industry—D. Swine Diseases

D. Swine Diseases 1. Diseases reported in 12-month period

Note: Due to differences in populations and question variation,

comparisons could not be made to the 1990 and 1995 studies.

PRRS diagnosis by a veterinarian or a laboratory remained unchanged across

both study periods and was the most prevalent of the listed diseases that were

diagnosed in the breeding herd by a veterinarian or laboratory during the

previous 12 months in 2000 and 2006.

a. Percentage of sites in which the following diseases were diagnosed in the

breeding herd by a veterinarian or laboratory during the previous 12 months:

 Swine 2000 Swine 2006 

Diseases Pct. 

Std. 

Error Pct. 

Std. 

Error 

PRRS 16.2 (2.6) 18.8 (3.3) 

APP 1.5 (0.4) 3.2 (1.8) 

Mycoplasma

pneumonia 7.3 (1.5) 8.8 (2.4) 

Roundworms 7.0 (3.0) 2.6 (1.5) 

Traditional swine flu 

(swine influenza virus 

H1N1) 6.8 (1.3) 5.6 (1.7) 

Gastric ulcers 4.7 (1.4) 9.3 (2.4) 

New swine flu (swine 

influenza virus H3N2) 4.5 (1.0) 4.8 (1.7) 

Glasser’s disease 

(Haemophilus parasuis) 3.0 (1.0) 1.8 (0.7) 

Parvovirus 2.3 (0.6) 3.8 (1.8) 

Erysipelas 1.9 (0.6) 3.9 (2.2) 
Section II: Health and Productivity Changes in the U.S. Pork Industry—D. Swine Diseases

28 / Swine 2006

The diagnosis of E.coli diarrhea in nursery pigs by a veterinarian or laboratory

was obtained in over twice as many sites in 2006 compared to 2000.

b. Percentage of sites in which the following diseases were diagnosed in

nursery pigs by a veterinarian or laboratory during the previous 12 months:

 Swine 2000 Swine 2006 

Disease Pct. 

Std. 

Error Pct. 

Std. 

Error 

PRRS 11.6 (3.2) 21.5 (3.2) 

Salmonella 4.5 (1.0) 4.0 (1.6) 

APP 3.8 (0.9) 1.2 (0.5) 

Streptococcus suis

(meningitis) 16.8 (2.6) 21.5 (3.1) 

Mycoplasma

pneumonia 10.3 (1.5) 12.6 (2.8) 

E. coli diarrhea 7.9 (1.2) 17.0 (3.1) 

Greasy pig disease 

(Staphylococcus 

hyicus) 7.1 (1.5) 8.9 (2.0) 

Glasser’s disease 

(Haemophilus 

parasuis) 6.0 (1.1) 12.8 (2.9) 

Traditional swine flu 

(swine influenza virus 

H1N1) 3.3 (0.9) 6.8 (1.8) 

Roundworms 0.5 (0.3) 2.1 (1.3) 
USDA APHIS VS / 29

Section II: Health and Productivity Changes in the U.S. Pork Industry—D. Swine Diseases

The percentage of grower/finisher sites in which traditional swine flu was

diagnosed by a veterinarian or laboratory increased from 5.8 percent in 2000 to

23.1 percent in 2006.

c. Percentage of sites in which the following diseases were diagnosed in grower/

finisher pigs by a veterinarian or laboratory during the previous 12 months:

 Swine 2000 Swine 2006 

Disease Pct. 

Std. 

Error Pct. 

Std. 

Error 

PRRS 10.3 (1.7) 23.4 (3.0) 

Salmonella 5.1 (1.1) 7.0 (1.4) 

APP 4.8 (0.9) 5.1 (1.3) 

Ileitis (Lawsonia 

intracellularis) 19.2 (2.5) 23.9 (3.2) 

Mycoplasma

pneumonia 16.0 (2.1) 22.5 (3.0) 

Roundworms 0.6 (0.3) 3.6 (2.2) 

Gastric ulcers 12.1 (2.2) 14.5 (2.2) 

Hemorrhagic bowel 

syndrome 11.3 (1.9) 18.9 (2.6) 

Atrophic rhinitis 3.4 (0.9) 1.3 (0.7) 

Traditional swine flu 

(swine influenza virus 

H1N1) 5.8 (1.0) 23.1 (2.9) 
Section II: Health and Productivity Changes in the U.S. Pork Industry—D. Swine Diseases

30 / Swine 2006
USDA APHIS VS / 31

Section III: Management Changes in the U.S. Pork Industry—A. Breeding Animals

Section III: Management Changes in the U.S. Pork Industry, NAHMS

Population Estimates—1990, 1995, 2000, and 2006

A. Breeding Animals

1. Mating techniques

The percentage of sites that used artificial insemination (AI) as the predominant

mating technique in sows and gilts increased from 2000 (24.3 and 28.7 percent,

respectively) to 2006 (40.1 and 41.8 percent, respectively). The percentage of

sows and gilts residing on operations that used AI as the predominant technique

has not changed substantially.

a. Percentage of sites that used AI as a predominant mating technique for sows

or gilts:

b. Percentage of sows or gilts serviced on sites that used AI as a predominant

mating technique:

Percent Sites 

2000 2006* 

Sows Gilts Sows Gilts 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

24.3 (1.8) 28.7 (2.2) 40.1 (2.1) 41.8 (2.5) 

*Question variation: Swine 2006 asked for information on first, second, or third or more matings. 

Swine 2000 only asked for first and second matings.

Percent Sows or Gilts 

2000 2006* 

Sows Gilts Sows Gilts 

Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

76.0 (2.0) 69.4 (3.3) 84.7 (4.5) 81.5 (3.1) 

*Question variation: Swine 2006 asked for information on first, second, or third or more matings. 

Swine 2000 only asked for first and second matings.

Note: Tables in Section III for all study years are for sites with 100 or more

pigs, unless otherwise noted.
Section III: Management Changes in the U.S. Pork Industry—A. Breeding Anijmals

32 / Swine 2006

2. Preventive practices for sows and gilts

The percentage of sites using routine preventive mange/lice treatment in sows

and gilts declined from 81.2 percent in 1995 to 52.8 percent in 2006. The

percentage of sites using preventive antibiotics in sows and gilts remained

unchanged from 1995 to 2006. A similar pattern was seen on sites with boars.

Note: In the 2006 study, data on preventive practices were collected for sows but

not for gilts.

For sites with sows and gilts on site, percentage of sites that reported regular

use of the following preventive practices:

Swine ’95 Swine 2000 Swine 2006* 

Practice Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Deworm 88.7 (1.5) 83.0 (1.9) 76.8 (1.9) 

Mange/lice 

treatment 81.2 (2.0) 67.9 (2.3) 52.8 (2.2) 

Antibiotics in feed 49.0 (2.8) 43.5 (2.5) 47.7 (2.2) 

Antibiotics in water 5.1 (1.1) 2.5 (0.6) 3.7 (0.9) 

Antibiotics by 

injection 37.4 (2.7) 38.5 (2.4) 40.8 (2.2) 

*Preventive practices for sows only.

3. Preventive practices for boars

For sites with boars on-site, percentage of sites that reported regular use of the

following preventive practices:

Swine ’95 Swine 2000 Swine 2006 

Practice Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Deworm 85.8 (1.7) 76.8 (2.1) 68.2 (2.0) 

Mange/lice 

treatment 78.8 (2.1) 65.0 (2.3) 51.3 (2.2) 

Antibiotics in feed 39.7 (2.7) 33.6 (2.4) 34.5 (2.2) 

Antibiotics in water 4.5 (1.1) 2.5 (0.6) 3.8 (0.9) 

Antibiotics by 

injection 28.9 (2.6) 25.6 (2.0) 23.2 (1.9) 
USDA APHIS VS / 33

Section III: Management Changes in the U.S. Pork Industry—B. Suckling Piglets

B. Suckling Piglets 1. Pig flow management

The percentage of sites that used continuous flow management in the farrowing

phase decreased from a high of 47.0 percent of sites in 1995 to a low of

33.5 percent of sites in 2006. From 2000 to 2006, the percentage of sites that

used all-in/all-out management by room in the farrowing phase increased from

25.2 to 37.1 percent, while the percentage of sites that used all-in/all-out

management by building decreased from 24.7 to 16.1 percent.

a. Percentage of sites that used the following types of pig management in the

farrowing phase:1

b. Percentage of sites that used the following types of all-in/all-out pig

management in the farrowing phase:

1990 National 

Swine Survey Swine ’95 Swine 2000 Swine 20062

Type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Continuous 

flow 41.8 (NA) 47.0 (2.7) 38.7 (2.5) 33.5 (2.1) 

All-in/all-out 58.2 (NA) 53.0 (2.7) 56.9 (2.5) 59.8 (2.2) 

Not applicable NA NA 4.4 (1.2) 6.7 (1.0) 

Total 100.0 100.0 100.0 100.0 

1

Question variation: The 1990 National Survey and Swine ’95 only asked if sites were continuous flow 

or all-in/all-out. Swine 2000 and Swine 2006 restricted continuous-flow and all-in/all-out categories to 

operations with swine housing (with an additional category for no housing). 

2

Response variation: In 2006 the management response “Not Applicable” changed to “Not Applicable 

(e.g., no housing).” 

Swine 2000 Swine 2006 

Percent Std. Error Percent Std. Error 

All swine removed without 

cleaning and disinfecting 

swine area 5.8 (1.4) 4.7 (1.1) 

All-in/all-out by room* 25.2 (1.7) 37.1 (2.0) 

All-in/all-out by building* 24.7 (2.2) 16.1 (1.6) 

All-in/all-out by site* 1.2 (0.5) 1.9 (0.6) 

Total 56.9 (2.5) 59.8 (2.2) 

*In 2006 the phrase “with (room, building, site) cleaned and disinfected” was added. 
Section III: Management Changes in the U.S. Pork Industry—B. Suckling Piglets

34 / Swine 2006

2. Waste management

For sites with total confinement farrowing facilities, the percentage of sites that

used no waste management system decreased to a nearly negligible amount

between 1995 and 2006. Hand cleaning declined from 28.3 percent of sites in

1995 to 8.6 percent in 2006, while slat flushing increased from 9.7 percent of

sites in 1995 to 26.2 percent in 2006. Since 1995, the majority of sites have used

pit-holding as a waste management system.

For sites with total confinement farrowing facilities, percentage of sites by type

of waste management system used in the farrowing phase:1

1990 National 

Swine Survey2

 Swine ’952 Swine 2000 Swine 2006 

Waste 

Management 

System Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

None 0.1 (0.1) 5.1 (1.9) 1.6 (0.6) 0.2 (0.1) 

Pit-holding 29.2 (2.5) 41.1 (2.9) 51.1 (2.8) 51.0 (2.6) 

Mechanical 

scraper/tractor 12.1 (3.3) 10.1 (1.8) 8.6 (1.6) 9.5 (1.7) 

Hand cleaned 41.6 (4.9) 28.3 (3.1) 11.6 (2.6) 8.6 (1.6) 

Flush-under slats 16.5 (2.2) 9.7 (1.3) 21.8 (2.1) 26.2 (2.2) 

Flush-open gutter 7.0 (1.4) 3.2 (0.9) 3.9 (0.9) 2.8 (0.8) 

Other 7.9 (1.7) 2.5 (0.8) 1.4 (0.4) 1.7 (0.7) 

Total NA 100.0 100.0 100.0 

1

Question variation: The 1990 National Survey asked if these waste management systems were ever used. 

Swine ’95, Swine 2000, and Swine 2006 asked which systems were used most. 

2

Operations with 1 or more hogs and pigs versus operations with 100 or more for the other studies. 
USDA APHIS VS / 35

Section III: Management Changes in the U.S. Pork Industry—B. Suckling Piglets

3. Preventive practices

The percentage of sites using deworming and mange/lice treatment preventive

practices in suckling piglets declined from 1995 to 2006.

For sites that had a farrowing phase, percentage of sites reporting regular use of

preventive practices on piglets before or at weaning:

4. Average weaning age

Average weaning age from 2000 to 2006 has remained stable.

Average age (in days) of piglets at weaning:

Average Age (Days)

1990 National 

Swine Survey* 

Swine ’95 

(12/94-5/95)* 

Swine 2000 

(12/99-5/00) 

Swine 2006 

(12/05-05/06) 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

28.8 (0.3) 25.7 (0.5) 19.3 (0.2) 19.4 (0.2) 

*Operations with 1 or more hogs and pigs versus operations with 100 or more for the other studies.

1990 National 

Swine Survey* 

Swine ’95 

(12/94-5/95) 

Swine 2000 

(12/99-5/00) 

Swine 2006 

(12/05-05/06) 

Preventive 

Practice Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Deworm 48.0 (2.9) 67.4 (2.4) 31.8 (2.3) 47.2 (2.2) 

Mange/lice 

treatment 40.2 (2.9) 65.9 (2.4) 29.0 (2.2) 36.5 (2.2) 

Antibiotics – 

injection 32.7 (2.7) 49.2 (2.8) 44.2 (2.3) 51.4 (2.2) 

Iron – oral or 

injection 85.6 (NA) 82.8 (2.0) 75.4 (2.2) 80.1 (1.8) 

*Operations with 1 or more hogs and pigs versus operations with 100 or more for the other studies. 
Section III: Management Changes in the U.S. Pork Industry—C. NurseryPigs

36 / Swine 2006

C. Nursery Pigs 1. Pig flow management

The percentage of sites using continuous flow management in the nursery phase

has decreased steadily since 1990. The percentage of sites using various levels

of all-in/all-out did not change substantially between 2000 and 2006.

a. Percentage of sites that used the following types of pig management in the

nursery phase:1

b. Percentage of sites that used the following types of all-in/all-out pig

management in the nursery phase:

1990 National 

Swine Survey Swine ’95 Swine 2000 Swine 20062

Type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Continuous flow 48.6 (NA) 45.9 (2.9) 32.3 (2.3) 25.0 (1.7) 

All-in/all-out 51.4 (NA) 54.1 (2.9) 64.1 (2.3) 71.0 (1.7) 

Not applicable NA NA 3.6 (1.1) 4.0 (0.7) 

Total 100.0 100.0 100.0 100.0 

1

Question variation: The 1990 National Survey and Swine ’95 only asked if sites were continuous flow or all-in/ 

all-out. Swine 2000 and Swine 2006 restricted continuous-flow and all-in/all-out categories to operations with 

swine housing (with an additional category for no housing). 

2

Response variation: In 2006 the management response “Not Applicable” changed to “Not Applicable (e.g., no 

housing).” 

Swine 2000 Swine 2006 

Percent Std. Error Percent Std. Error 

All swine removed without 

cleaning and disinfecting 

swine area 3.9 (1.2) 3.6 (0.8) 

All-in/all-out by room* 24.4 (1.6) 30.5 (1.6) 

All-in/all-out by building* 32.3 (2.1) 29.8 (1.6) 

All-in/all-out by site* 3.5 (0.7) 7.1 (1.0) 

Total 64.1 (2.3) 71.0 (1.7) 

*In 2006 the phrase “with (room, building, site) cleaned and disinfected” was added. 
USDA APHIS VS / 37

Section III: Management Changes in the U.S. Pork Industry—C. NurseryPigs

2. Age leaving nursery

The average age that pigs left the nursery phase increased from 60.3 days in

1995 to 64.8 days in 2006.

a. Average age (in days) of pigs leaving the nursery:

Average Age (Days) 

1990 National 

Swine Survey* Swine ’95* Swine 2000 Swine 2006 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

62.0 (0.5) 60.3 (0.8) 63.3 (0.5) 64.8 (0.5) 

*Operations with 1 or more hogs and pigs versus operations with 100 or more for the other studies. 
Section III: Management Changes in the U.S. Pork Industry—D. Grower/Finisher Pigs

38 / Swine 2006

D. Grower/Finisher Pigs 1. Pig flow management

The percentage of sites that used continuous flow management in the grower/

finisher phase decreased steadily from 75.1 percent of sites in 1990 to

26.1 percent in 2006. The percentage of sites that used all-in/all-out

management by room increased from 10.7 percent of sites in 2000 to

17.5 percent in 2006.

Percentage of sites that used the following types of pig management in the

grower/finisher phase:1

b. Percentage of sites that used the following types of all-in/all-out pig

management in the grower/finisher phase:

1990 National 

Swine Survey Swine ’95 Swine 2000 Swine 20062

Type Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Continuous 

flow 75.1 (NA) 60.0 (NA) 40.5 (2.0) 26.1 (1.3) 

All-in/all-out 24.9 (NA) 40.0 (2.5) 56.9 (2.0) 70.8 (1.4) 

Not applicable NA NA 2.6 (0.7) 3.1 (0.5) 

Total 100.0 100.0 100.0 100.0 

1

Question variation: The 1990 National Survey and Swine ’95 only asked if sites were continuous flow 

or all-in/all-out. Swine 2000 and Swine 2006 restricted continuous-flow and all-in/all-out categories to 

operations with swine housing (with an additional category for no housing). 

2

Response variation: In 2006 the management response “Not Applicable” changed to “Not Applicable 

(e.g., no housing).” 

Swine 2000 Swine 2006 

Percent Std. Error Percent Std. Error 

All swine removed without 

cleaning and disinfecting 

swine area 3.2 (0.7) 6.2 (0.8) 

All-in/all-out by room* 10.7 (0.9) 17.5 (1.2) 

All-in/all-out by building* 32.3 (1.7) 35.0 (1.3) 

All-in/all-out by site* 10.7 (1.1) 12.1 (1.0) 

Total 56.9 (2.0) 70.8 (1.4) 

*In 2006 the phrase “with (room, building, site) cleaned and disinfected” was added. 
USDA APHIS VS / 39

Section III: Management Changes in the U.S. Pork Industry—D. Grower/Finisher Pigs

2. Market age

The average age that pigs left the grower/finisher phase was virtually unchanged

from 1990 to 2006.

Average age (in days) of pigs leaving the grower/finisher unit:

Average Age (Days) 

1990 National 

Swine Survey* Swine ’95* Swine 2000 Swine 2006 

Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error Avg. 

Std. 

Error 

180.0 (0.5) 176.4 (1.0) 177.6 (1.1) 179.7 (1.3) 

*Operations with 1 or more hogs and pigs versus operations with 100 or more for the other studies. 
Section III: Management Changes in the U.S. Pork Industry—E. General Farm Management

40 / Swine 2006

E. General Farm

Management

1. Vaccination practices

The regular use of influenza vaccines in breeding females more than doubled

between 2000 and 2006.

Percentage of sites with the following production phases during the 12 months

prior to the survey1 that usually vaccinated within the production phases against

the listed diseases:

Breeding Females Weaned Pigs2

Swine 2000 Swine 2006 Swine 2000 Swine 2006 

 

Disease 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

Mycoplasma

pneumonia 20.9 (2.9) 34.9 (4.2) 40.0 (3.6) 35.6 (3.2) 

PRRS 37.1 (4.7) 27.3 (3.9) 5.2 (1.1) 5.4 (1.6) 

Swine 

influenza H1N1 11.2 (1.8) 27.9 (3.8) 4.8 (0.9) 9.5 (1.7) 

Swine 

influenza H3N2 10.6 (1.9) 27.8 (3.8) 5.0 (1.0) 8.7 (1.6) 

1

August 21-October 31, 1999, and September 5, 2005-March 15, 2006. 

2

Weaned pigs are those in a nursery or grower/finisher stage. 
USDA APHIS VS / 41

Section III: Management Changes in the U.S. Pork Industry—E. General Farm Management

2. Isolation or quarantine of new arrivals

Isolating or quarantining new breeding stock can maintain biosecurity and

prevent the introduction of new disease in the breeding herd. In 2006, about

one-third of sites (34.3 percent) always isolated new breeding females, while

about one-fourth of sites (23.8 percent) did so in 1995.

a. Percentage of sites by frequency of placing new arrivals through an isolation

or quarantine process:

Breeding Females Breeding Males 

Swine ‘95 Swine 2000 Swine 2006 Swine ‘95 Swine 2000 Swine 2006 

 

Frequency 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

Always 23.8 (2.1) 32.0 (2.2) 34.3 (2.0) 43.5 (2.4) 54.8 (2.4) 48.6 (2.2) 

Sometimes 9.0 (1.3) 8.1 (1.4) 5.0 (0.9) 11.1 (1.7) 11.3 (1.6) 10.1 (1.4) 

Never 22.0 (2.2) 16.9 (1.8) 17.0 (1.6) 18.2 (1.8) 20.2 (2.0) 20.2 (1.8) 

No new 

arrivals 45.2 (2.6) 43.0 (2.4) 43.7 (2.2) 27.2 (2.3) 13.7 (1.5) 21.1 (1.7) 

Total 100.0 100.0 100.0 100.0 100.0 100.0 
Section III: Management Changes in the U.S. Pork Industry—E. General Farm Management

42 / Swine 2006

The percentage of sites that health tested new breeding females and males has

remained essentially unchanged since 1995.

b. For sites that isolated or quarantined new arrivals, percentage of sites that

health tested these arrivals (either before or after isolation), by proportion of

animals tested:

Breeding Females Breeding Males 

Swine ‘95 Swine 2000 Swine 2006 Swine ‘95 Swine 2000 Swine 2006 

 

Proportion 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

All 42.0 (4.4) 43.5 (3.7) 42.1 (3.3) 44.4 (3.3) 51.8 (3.1) 46.3 (2.9) 

Some 30.6 (3.8) 16.8 (2.4) 24.4 (2.9) 20.0 (2.4) 8.3 (1.4) 14.8 (2.2) 

None 27.4 (3.6) 39.7 (3.8) 33.5 (3.1) 35.6 (3.2) 39.9 (3.2) 38.9 (2.8) 

Total 100.0 100.0 100.0 100.0 100.0 100.0 

3. Carcass disposal

The methods of disposing of carcasses have changed. For example, the

percentage of sites that disposed of dead pigs by burying on-site decreased from

62.4 percent in 1990 to 26.3 percent in 2006. Conversely, the percentage of sites

that disposed of dead pigs by composting on-site increased from 16.4 percent in

1995 to 35.0 percent in 2006.
USDA APHIS VS / 43

Section III: Management Changes in the U.S. Pork Industry—E. General Farm Management

Percentage of sites by method of carcass disposal:

1990 National 

Swine Survey* 

Swine ’95 

(12/94-5/94) 

Swine 2000 

(12/99-5/00) Swine 2006 

 

Method 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

 

Pct. 

Std. 

Error 

Burial on-site 62.4 (3.2) 55.4 (3.0) 52.5 (2.6) 26.3 (1.2) 

Burning on-site 21.6 (2.1) 14.0 (1.8) 18.0 (2.0 13.7 (0.9) 

Renderer 

entering site 

 

26.6 

 

(2.5) 

 

31.6 

 

(2.6) 

 

31.1 

 

(2.5) 25.7 (1.2) 

Renderer at 

site perimeter 29.8 (3.3) 10.1 (1.5) 9.1 (1.4) 10.4 (0.9) 

Composting 

on-site NA 16.4 (2.1) 23.5 (2.2) 35.0 (1.3) 

Other 17.6 (2.2) 6.8 (1.4) 4.9 (1.2) 2.7 (0.4) 

*Operations with 1 or more hogs and pigs versus operations with 100 or more for the other studies.
Section III: Management Changes in the U.S. Pork Industry—E. General Farm Management

44 / Swine 2006

4. Rodent control

The percentage of sites that used cats to control rodents decreased from

87.0 percent in 1990 to 51.2 percent in 2006.

Percentage of sites that regularly used rodent control, by method:

1990 National 

Swine Survey 

 

Swine ’95 

 

Swine 2000 Swine 2006 

 

Method Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Cats 87.0 (NA) 68.7 (2.2) 60.6 (1.7) 51.2 (1.3) 

Traps 14.7 (NA) 15.9 (1.6) 19.6 (1.5) 20.5 (1.1) 

Bait or poison 85.1 (NA) 85.1 (1.9) 88.5 (1.2) 87.9 (0.9) 

Dog NA NA 33.9 (1.8) 26.3 (1.2) 

Professional 

exterminator NA NA 4.4 (0.5) 5.4 (0.5) 

Other 5.9 (NA) 9.5 (1.7) 2.6 (0.9) 1.8 (0.4) 
USDA APHIS VS / 45

Section III: Management Changes in the U.S. Pork Industry—E. General Farm Management

5. Proximity to nearest swine farm or market

The percentage of sites within 0.5 miles of another swine site increased from

20.2 percent in 1990 to 29.6 percent in 2006.

Percentage of sites by distance in miles from the nearest known swine site:

1990 National 

Swine 

Survey1 2 Swine ’951 2 Swine 20001

 Swine 2006 

 

Miles Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Less than 0.50 20.2 (NA) 25.9 (NA) 28.3 (NA) 29.6 (1.3) 

0.50 to 0.99 31.1 (2.9) 21.3 (1.9) 25.6 (1.6) 23.2 (1.1) 

1.0 to 2.99 31.2 (2.7) 29.1 (2.1) 27.9 (1.5) 27.5 (1.2) 

3.0 to 4.99 5.6 (1.3) 11.9 (1.7) 9.3 (0.9) 10.4 (0.8) 

5.0 or more 11.8 (4.0) 11.8 (1.6) 8.9 (0.9) 9.3 (0.7) 

Unknown 0.1 (0.1) NA NA NA 

Total 100.0 100.0 100.0 100.0 

1

Question variation: Surveys from 1990-2000 asked distance to nearest 0.1 mile. Swine 2006 asked 

distance to nearest 0.25 mile. 

2

Operations with 1 or more hogs and pigs versus operations with 100 or more for the other studies.
Section IV: Trends in Other National Data Bases—A. Slaughter Condemnation Rates

46 / Swine 2006

Section IV: Trends in Other National Data Bases

A. Slaughter

Condemnation Rates

in Federally Inspected

Slaughter Plants, 1996

Through 2006

1. Market pigs

Market pig condemnation rates for dead pigs peaked in 1998 at 2.9 per

1,000 pigs slaughtered. Dead pigs were the largest single reason for market pig

condemnation. Condemnation rates for abscesses or pyemia (septicemia

caused by microorganisms in the blood, often resulting in the formation of

multiple abscesses) decreased steadily from a peak of 0.23 per 1,000 head in

1997 to 0.09 per 1,000 head in 2005. Condemnation rates for arthritis gradually

declined between 1996 and 2006.

a. Rate of condemnations per 1,000 pigs slaughtered for selected dispositions,

by year:*

Disposition 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Avg. 

Deads 2.096 2.454 2.948 2.885 2.847 2.896 2.433 2.131 2.266 2.208 2.189 2.487 

Abscess 

Pyemia 0.209 0.231 0.169 0.151 0.137 0.192 0.182 0.186 0.096 0.090 0.091 0.158 

Arthritis 0.092 0.097 0.082 0.059 0.080 0.083 0.083 0.074 0.060 0.042 0.030 0.071 

Pneumonia 0.115 0.148 0.120 0.101 0.099 0.098 0.106 0.095 0.070 0.070 0.074 0.100 

Septicemia 0.092 0.137 0.119 0.132 0.138 0.171 0.161 0.143 0.134 0.126 0.141 0.136 

Erysipelas 0.060 0.050 0.038 0.039 0.046 0.090 0.056 0.045 0.036 0.041 0.042 0.049 

Toxemia 0.025 0.032 0.032 0.031 0.046 0.040 0.032 0.032 0.023 0.026 0.024 0.031 

Nephritis 0.017 0.019 0.015 0.011 0.015 0.015 0.014 0.014 0.014 0.011 0.013 0.014 

Pericarditis 0.011 0.018 0.022 0.031 0.026 0.019 0.022 0.017 0.083 0.020 0.014 0.026 

*Source: Food Safety Inspection Service (FSIS).
USDA APHIS VS / 47

Section IV: Trends in Other National Data Bases—A. Slaughter Condemnation Rates

The number of market pig carcasses condemned for metritis has steadily

declined since 2001. The number of carcasses condemned for residues dropped

from 1996 to 2004, but rose between 2005 and 2006.

b. Number of condemnations for selected dispositions, by year:*

Disposition 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Avg. 

CNS disorder 271 449 995 381 622 1,601 688 346 181 249 283 551 

Residue 81 8 62 22 12 0.0 0.0 0.0 0.0 23 25 21 

Metritis 35 21 94 41 33 69 32 22 31 7 11 36 

Tetanus 0.0 29 0.0 1 36 0.0 34 105 0.0 0.0 0.0 19 

Actinomycosis 16 1 189 37 50 16 8 2 0.0 1 1 29 

Eosinophilic 

myositis 0.0 0.0 19 2 7 0.0 3 2 1 3 4 4 

Cysticercosis 0.0 0.0 1 1 0.0 0.0 4 0.0 0.0 3 1 1 

*Source: FSIS.
Section IV: Trends in Other National Data Bases—A. Slaughter Condemnation Rates

48 / Swine 2006

2. Sows

Cull sow condemnation rates for deads increased from 2.6 per 1,000 sows

slaughtered in 1996 to over 6 per 1,000 sows slaughtered in 2000, but was back

down to 4.3 per 1,000 sows slaughtered in 2006. In sows, condemnation rates

due to pneumonia peaked at nearly 1 per 1,000 sows slaughtered in 2004.

a. Rate of condemnations per 1,000 sows slaughtered for selected dispositions,

by year:*

Disposition 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Avg. 

Deads 2.603 3.366 3.022 3.485 6.050 3.946 3.885 3.519 3.515 4.021 4.312 3.793 

Abscess 

Pyemia 1.219 1.097 1.050 1.364 1.586 1.254 1.102 0.614 0.542 0.676 0.673 1.016 

Arthritis 0.195 0.031 0.089 0.028 0.053 0.051 0.043 0.020 0.009 0.004 0.006 0.048 

Pneumonia 0.501 0.400 0.411 .0475 0.548 0.537 0.471 0.707 0.937 0.620 0.795 0.543 

Septicemia 0.311 0.532 0.417 0.404 0.764 0.614 0.740 0.448 0.554 0.502 0.411 0.518 

Erysipelas 0.020 0.038 0.035 0.034 0.046 0.010 0.005 0.003 0.007 0.011 0.027 0.021 

Toxemia 0.155 0.240 0.279 0.307 0.175 0.095 0.131 0.651 0.894 0.930 0.633 0.408 

Nephritis 0.042 0.044 0.046 0.016 0.040 0.061 0.059 0.038 0.053 0.082 0.100 0.053 

Pericarditis 0.106 0.041 0.063 0.092 0.127 0.243 0.208 0.200 0.131 0.138 0.114 0.133 

*Source: FSIS.
USDA APHIS VS / 49

Section IV: Trends in Other National Data Bases—A. Slaughter Condemnation Rates

The number of sow carcasses condemned for metritis declined from 216

carcasses in 1997 to 44 carcasses in 2004, then increased the next 2 years,

reaching 176 carcasses in 2006. Similar to market swine, the number of sow

carcasses condemned for residues was small or nonexistent from 1996 to 2004,

but increased between 2005 and 2006.

b. Number of condemnations for selected dispositions, by year:*

Disposition 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Avg. 

CNS disorder 59 69 78 23 106 104 107 68 7 30 48 64 

Residue 3 0.0 1 1 0.0 0.0 0.0 0.0 0.0 17 20 4 

Metritis 43 216 141 37 49 77 75 49 44 110 176 92 

Tetanus 4 9 3 4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 

Actinomycosis 13 1 0.0 1 1 1 2 0.0 0.0 0.0 0.0 2 

Eosinophilic 

myositis 0.0 0.0 1 0.0 1 1 5 0.0 0.0 0.0 0.0 1 

Cysticercosis 0.0 0.0 0.0 0.0 10 20 27 8 10 13 2 7 

*Source: FSIS. 
Section IV: Trends in Other National Data Bases—B. Salmonella Serotypes

50 / Swine 2006

B. Salmonella Serotypes 1. Most frequently identified serotypes

The table below lists the top 10 Salmonella serotypes found in swine, from the

most frequent to the least frequent, based on 2001 rankings. Cholerasuis (var.

Kunzendorf), Derby, and Typhimurium (var. Copenhagen) are consistently

identified by the National Veterinary Services Laboratories (NVSL) as in the top

five most frequent isolates for the 6 years presented. Typhimurium was in the top

five for 5 out of 6 years (ranking 7 in 2004). S. Typhimurium (var. Copenhagen)

has been the most frequently isolated serotype each year, with the exception of

2002.

Most frequently identified Salmonella serotypes1 2 from swine, by year:

 2001 2002 2003 2004 2005 2006 

Serovar Number 

Isolates Rank 

Number 

Isolates Rank 

Number 

Isolates Rank 

Number 

Isolates Rank 

Number 

Isolates Rank 

Number 

Isolates Rank 

Typhimurium 

(var. 

Copenhagen) 672 1 382 2 310 1 767 1 910 1 589 1 

Typhimurium 501 2 99 4 65 5 126 7 183 4 170 4 

Cholerasuis 

(var. 

Kunzendorf) 264 3 206 3 167 3 218 3 176 5 159 5 

Derby 261 4 426 1 242 2 545 2 554 2 371 2 

Agona 170 5 99 4 59 6 104 8 146 6 154 6 

Heidelberg 123 6 78 6 75 4 128 6 187 3 288 3 

Worthington 97 7 -- -- 54 7 -- -- 115 8 -- -- 

Infantis 87 8 56 7 35 8 199 4 103 9 80 8 

Anatum 74 9 34 10 26 9 152 5 146 6 76 9 

Newport 35 10 -- -- -- -- 59 10 -- -- 90 7 

Brandenburg -- -- 53 8 -- -- -- -- -- -- -- -- 

6,7:Z10-

Monophasic -- -- 38 9 -- -- -- -- -- -- -- -- 

6,7:Nonmotile -- -- -- -- 25 10 -- -- -- -- -- -- 

Mbandaka -- -- -- -- -- -- 62 9 -- -- -- -- 

Uganda -- -- -- -- -- -- -- -- 85 10 -- -- 

Senftenberg -- -- -- -- -- -- -- -- -- -- 61 10 

Top 10 

(number and 

percent) 2,284 82.8 1,471 79.7 1,058 79.1 2,360 77.2 2,605 78.4 2,038 73.4 

All others 

(number and 

percent) 474 17.2 375 20.3 280 20.9 696 22.8 719 21.6 740 26.6 

Total (number 

and percent) 2,758 100.0 1,846 100.0 1,338 100.0 3,056 100.0 3,324 100.0 2,778 100.0 1

Source: NVSL—data reflect all isolates from samples submitted to NVSL for serotyping for the calendar year January through 

December. The data may not necessarily reflect the population of Salmonella in swine throughout the United States. 2

For 1990-2000 numbers, see NAHMS Swine 2000 at: http://nahms.aphis.usda.gov
USDA APHIS VS / 51

Appendix: Swine 2006 Study Objectives and Related Outputs

Appendix: Swine 2006 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 Practices in the

United States, 2006, December 2007

• Part III: Reference of Swine Health, Productivity, and General Management,

2006, March 2008

• Info sheets, expected winter 2008

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 Practices in the

United States, 2006, December 2007

• Part III: Reference of Swine Health, Productivity, and General Management,

2006, March 2008

• Info sheets, expected spring 2008

3. Examine vaccination and antimicrobial use practices.

• Part II: Reference of Swine Health and Health Management Practices in the

United States, December 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, November 2008

• Info sheets, November 2008