United States

Department of

Agriculture

Animal and

Plant Health

Inspection

Service

Veterinary

Services

National

Animal Health

Monitoring

System

November 2006

Sheep and Lamb

Nonpredator Death Loss in

the United States, 2004
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

www.aphis.usda.gov/vs/ceah/ncahs

#N445.1106

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Cover photo courtesy of ARS
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).

Thank you to the NASS enumerators who telephoned and visited sheep

operations 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.

José Dßez

Acting Director

Centers for Epidemiology and Animal Health
ii / Sheep Death Loss, 2004

Suggested bibliographic citation for this report:

USDA. 2005. Sheep and Lamb Nonpredator Death Loss in the United States,

2004

USDA:APHIS:VS,CEAH, National Animal Health Monitoring System, Fort Collins,

CO #N445.0906

Contacts for further information:

Questions or comments on the Sheep and Lamb Death Loss, 2004 study

methods or requests for additional data analysis: Dr. Katherine Marshall

970.494.7000

Information on reprints or other NAHMS reports: Ms. Anne Berry: 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—Number of Head 3

A. U.S. Demographics 3

1. Inventory, January 1, 1994 to 2005 3

2. Operations, 1994 to 2004 3

3. Lamb crop—1994 to 2004 5

B. Regional Demographics 6

1. Adult sheep inventory—January 1, 1995, 2000, and 2005 6

2. Lamb crop—1994, 1999, and 2004 7

C. U.S. Annual Death Loss 7

1. Loss from all causes, 1994 to 2004 7

2. U.S. nonpredator and predator death loss—1994, 1999, and 2004 10

3. Regional predator and nonpredator death loss—1994, 1999, and

 2004 12

Section II: Population Estimates—Nonpredator Losses 17

A. Nonpredator Sheep Death Loss 17

1. Losses—2004 17

2. Cause of loss—1994, 1999, and 2004 18

3. Cause of loss by size of operation—2004 20

4. Cause of loss by region—2004 22

5. Cause of loss by region and by size of operation—2004 24

B. Nonpredator Lamb Death Loss 29

1. Losses—2004 29

2. Cause of loss—1994, 1999, and 2004 31

3. Cause of loss by size of operation—2004 33

4. Cause of loss by region—2004 35

5. Cause of loss by region and by size of operation—2004 37

Section III: Methodology 42

A. 1994 Death Loss Study 42

1. Survey procedures 42

2. Estimation procedures 42

3. Reliability 42

B. 1999 Death Loss Study 43

1. Survey procedures 43

2. Estimation procedures 43

3. Revision policy 43

C. 2004 Death Loss Study 44

1. Survey procedures 44

2. Estimation procedures 44

3. Revision policy 44

Appendix: Discussion of Pre- and Postdocking Losses 45
Introduction

USDA APHIS VS / 1

Introduction

Each January, USDA’s National Agricultural Statistics Service (NASS) collects

sheep data on inventory, lamb crop, and total sheep and lamb death loss.

Inventory and lamb crop estimates (number of head) are published in January

via the “Sheep and Goats” report. Sheep and lamb death loss (number of head)

are published in April via the “Meat Animals Production, Disposition and Income”

report. For NASS’ January 1995, 2000, and 2005 sheep surveys, USDA’s Animal

and Plant Health Inspection Service (APHIS) provided funding for a detailed,

retrospective breakdown of total sheep and lamb loss by producer-attributed

cause of loss occurring during the previous year. Death losses by predator and

nonpredator causes were published by NASS for losses in 2004.

This report provides a breakdown of sheep and lamb death loss in 2004 for all

causes by size group and region, with special emphasis on nonpredator causes

of loss. Where possible, the 1994 and 1999 death losses are provided for

comparison. For specifc information on predator losses by type, refer to the

NASS report “Sheep and Goats Death Loss” released May 6, 2005,

<www.nass.usda.gov>.

The methods used in the study can be found at the end of this report.

Further information on NAHMS studies and reports is available online at:

<http://nahms.aphis.usda.gov>.

For questions about this report or additional copies, please contact:

USDA:APHIS:VS:CEAH

NRRC Building B, M.S. 2E7

2150 Centre Avenue

Fort Collins, CO 80526-8117

970.494.7000
Introduction

2 / Sheep Death Loss, 2004

Terms Used In

This Report

Adult sheep inventory: Breeding rams and ewes 1 year and older, and market

sheep.

Lamb crop: For the Central, Northeast, and Southeast/Other regions (see

regions listed below), all lambs born alive during the calendar year. For the

Pacific and West Central regions, all lambs after docking, marking, or branding

during the calendar year.

Lambs: Animals less than 1 year old.

Lamb losses: For the Central, Northeast, and Southeast/Other regions, lamb

losses were tallied for all lambs born alive. In the Pacific and West Central

regions, lamb losses were tallied for lambs after docking, marking, or branding.

For a discussion of predocking losses, see Appendix.

Market sheep: Animals 1 year and older for use as feeders or for slaughter.

N/A: Not available.

Regions:

Pacific: California, Oregon, Washington

West Central: Arizona, Colorado, Idaho, Montana, New Mexico, Nevada,

Texas, Utah, and Wyoming

Central: Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri,

Nebraska, North Dakota, Oklahoma, South Dakota, and Wisconsin

Northeast: Connecticut, Maine, Massachusetts, New Hampshire, New York,

Ohio, Pennsylvania, Rhode Island*, Virginia, Vermont, and West Virginia

Southeast/Other: Alabama, Alaska, Arkansas, Delaware, Florida, Georgia,

Hawaii, Kentucky, Louisiana, Maryland, Mississippi, New Jersey, North Carolina,

South Carolina, and Tennessee

*For the 1994 estimates, Rhode Island was included in the Southeast/Other

region. In 1999 and 2004, Rhode Island was included in the Northeast region.

Size of Operation: Number of sheep and lambs on the operation January 1 of

respective year. Size groups are: 1 to 24; 25 to 99; 100 to 999; and 1,000 head

or more.
Section I: Population Estimates, Number of Head

USDA APHIS VS / 3

Section I: Population Estimates—Number of Head

A. U.S. Demographics* 1. Inventory, January 1, 1994 to 2005

a. Number of sheep and lambs by class and by year: (table revised 3-19-07)

2. Operations, 1994 to 2004

a. Number of operations with sheep and lambs by year:

*”Sheep and Goats” annual January report, NASS

Number Operations 

Year 

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 

86,060 79,900 76,600 72,680 71,750 70,000 69,200 68,600 68,150 67,720 67,580 

 January 1 Number (1,000 Head) 

Year 

Class 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 

All sheep 

and lambs 9,835.7 8,989.3 8,464.6 8,023.7 7,825.1 7,247.0 7,036.0 6,908.0 6,623.0 6,321.0 6,105.0 6,135.0 

Breeding 

ewes 1 year 

and older 5,844.4 5,403.6 5,134.3 4,911.6 4,569.5 4,336.0 4,234.0 4,071.0 3,939.0 3,773.0 3,609.5 3,572.5 

Breeding 

rams 1 year 

and older 294.1 257.0 233.8 220.3 202.8 202.5 208.5 202.0 200.5 194.0 188.0 190.0 

Market 

sheep N/A 96.8 77.4 85.1 90.8 82.5 80.0 79.0 72.6 67.8 65.6 74.1 

Breeding 

ewes and 

rams 1 year 

and older 

and market 

sheep N/A 5,757.4 5,445.5 5,217.0 4,863.1 4,621.0 4,522.5 4,352.0 4,212.1 4,034.8 3,863.1 3,836.6 
Section I: Population Estimates, Number of Head

4 / Sheep Death Loss, 2004

b. Percentage of operations with breeding sheep by size of operation and by

year:

c. Percentage of breeding sheep inventory by size of operation and by year:

Percent Inventory 

Year 

Size of 

Operation 

(Number of 

Breeding Sheep) 1994 1995 1996 1997 1998 1999 2000* 2001 2002 2003 2004 

1 to 99 22.3 24.1 25.0 25.7 25.5 25.9 27.9 28.8 30.1 29.9 31.7 

100 to 499 22.9 19.9 20.4 20.3 19.2 20.4 22.0 23.8 23.5 23.8 22.0 

500 to 4,999 38.4 41.4 40.9 40.0 42.6 39.0 35.2 33.7 32.4 33.1 33.0 

5,000 or more 16.4 14.6 13.7 14.0 12.7 14.7 14.8 13.7 14.0 13.2 13.3 

Total 100.0 100.0 100.0 100.0 100.0 100.0 99.9 100.0 100.0 100.0 100.0 

*Does not sum to 100.0 due to rounding 

 Percent Operations 

 Year 

Size of 

Operation 

(Number of 

Breeding 

Sheep) 1994 1995 1996 1997 1998 1999 2000* 2001 2002 2003 2004 

1 to 99 89.6 91.2 90.9 91.9 90.8 90.6 91.2 90.8 91.1 91.8 92.2 

100 to 499 8.2 6.7 7.0 6.2 6.8 7.3 7.2 7.5 7.3 6.7 6.3 

500 to 4,999 2.1 2.0 2.0 1.8 2.3 2.0 1.6 1.6 1.5 1.4 1.4 

5,000 or more 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 

Total 100.0 100.0 100.0 100.0 100.0 100.0 100.1 100.0 100.0 100.0 100.0 

*Does not sum to 100.0 due to rounding 
USDA APHIS VS / 5

Section I: Population Estimates, Number of Head

3. Lamb crop—1994 to 2004

a. Lamb crop and lamb crop per 100 ewes on hand, by year:

 Year 

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 

Lamb crop

(1,000 

Head) 5,968.2 5,643.2 5,361.3 5,356.3 5,001.5 4,754.0 4,645.0 4,519.5 4,355.0 4,140.0 4,096.0 

Lamb crop 

per 100 

ewes on 

hand 

beginning 

of year 

(January 1) 102 104 104 109 109 110 110 111 111 110 113 

Photo courtesy of ARS
Section I: Population Estimates, Number of Head

6 / Sheep Death Loss, 2004

B. Regional

Demographics

For this report, the United States was divided into five regions (see Terms Used

in This Report, p. 1) in order to provide data on smaller geographic areas.

NASS does not publish inventory and death loss data for small sheepproducing States individually, but collapses the data into an “Other States”

group. For estimates in this report, the “Other States” were combined with the

Southeast region. About 4 percent of U.S. sheep and lamb death loss occurred

in the “Other States.”

1. Adult sheep inventory—January 1, 1995, 2000, and 2005

Nationally, the sheep population declined from approximately 5.8 million head

on January 1, 1995, to approximately 3.8 million head on January 1, 2005.

Regionally, only the Southeast/Other region showed an increase in sheep

population from 1995 to 2005. A similar trend occurred in lamb-crop size during

the same period (table 2a.)

a. Number of adult sheep (and number of adult sheep in 2000 as a percentage

of adult sheep inventory in 1995), by region:

January 1 Number (1,000 Head) Percent 

Region 1995 2000 2005 

2005 as a 

percentage 

of 1995 

2005 as a 

percentage 

of 2000 

Pacific 740.0 506.5 447.2 60.4 88.3 

West Central 3,237.0 2,547.0 1,974.0 61.0 77.5 

Central 1,258.0 1,032.5 957.8 76.1 92.8 

Northeast 400.0 309.5 314.9 78.7 101.7 

Southeast/Other 122.4 127.0 142.7 116.6 112.4 

Total 5,757.4 4,522.5 3,836.6 66.6 84.8 
USDA APHIS VS / 7

Section I: Population Estimates, Number of Head

2. Lamb crop—1994, 1999, and 2004

a. Calendar year lamb crop (and 2004 lamb crop as a percentage of 1999 and

1994 lamb crops), by region: (table revised 3-19-07)

C. U.S. Annual

Death Loss

1. Loss from all causes, 1994 to 2004

A total of 385,000 lambs and 215,300 sheep were lost due to predator and

nonpredator causes in 2004. These totals represent 9.4 and 5.6 percent of

lamb crop and sheep inventory, respectively. While the sheep death loss

percentage remained relatively stable since 1994, the lamb death loss

percentage declined steadily during the same period.

a. Sheep and lamb death loss due to all causes, by year:*

 Number (1,000 Head) 

Year 

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 

Sheep 332.8 314.4 342.6 305.4 297.0 259.8 281.5 274.7 261.7 238.4 215.3 

Lamb 614.7 580.4 578.8 542.8 507.1 488.6 490.2 474.8 428.8 393.8 385.0 

Total 947.5 894.8 921.4 848.2 804.1 748.4 771.7 749.5 690.5 632.2 600.3 

*Meat Animal Production, Disposition, and Income, annual April report, NASS. 

Lamb Crop (1,000 Head) Percent 

Region 1994 1999 2004 

2004 as a 

percentage 

of 1994 

2004 as a 

percentage 

of 1999 

Pacific 695.0 494.0 458.0 65.9 92.7 

West Central 3,124.0 2,495.0 1,921.0 61.5 77.0 

Central 1,574.0 1,298.0 1,227.0 78.0 94.5 

Northeast 470.7 367.0 368.0 78.2 100.3 

Southeast/Other 104.5 100.0 122.0 116.7 122.0 

Total 5,968.2 4,754.0 4,096.0 68.6 86.2 
Section I: Population Estimates, Number of Head

8 / Sheep Death Loss, 2004

b. Sheep death loss as a percentage of January 1 inventory of adult sheep

inventory on January 1 of the following year, by year:

Percent Inventory 

Year 

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 

5.8 5.8 6.6 6.3 6.4 5.7 6.5 6.5 6.5 6.2 5.6 
USDA APHIS VS / 9

Section I: Population Estimates, Number of Head

c. Lamb death loss as a percentage of lamb crop, by year:

Percent Lamb Crop 

Year 

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 

10.3 10.3 10.8 10.1 10.1 10.3 10.6 10.5 9.8 9.5 9.4 
Section I: Population Estimates, Number of Head

10 / Sheep Death Loss, 2004

2. U.S. nonpredator and predator death loss*—1994, 1999, and 2004

Since 1994, nonpredator causes have accounted for the majority of sheep and

lamb death loss. In 2004, 62.7 percent of losses were due to nonpredator

causes.

a. Number of sheep and lamb death losses by cause and percentage of loss by

cause—by year:

As in 1994 and 1999, a higher percentage of lamb losses (41.0 percent) than

sheep losses (30.8 percent) were due to predators in 2004.

b. Number of sheep death losses by cause and percentage of loss by cause—

by year:

Number and Percent Loss 

 Year 

 1994 1999 2004 

Cause Number Percent Number Percent Number Percent 

Nonpredator 230,025 68.3 183,400 70.6 148,900 69.2 

Predator 106,575 31.7 76,400* 29.4 66,400 30.8 

Total 336,600 100.0 259,800 100.0 215,300 100.0 

*Initial NASS publication showed predator sheep losses of 77,000 head. Subsequent publication only revised 

total sheep loss. Relationship between predator and nonpredator loss was maintained at the State level, 

therefore deriving 76,400 head lost due to predators in the United States. 

Number and Percent Loss 

Year 

1994 1999 2004 

Cause Number Percent Number Percent Number Percent 

Nonpredator 577,950 61.1 472,700 63.2 376,100 62.7 

Predator 368,050 38.9 275,700 36.8 224,200 37.3 

Total 946,000 100.0 748,400 100.0 600,300 100.0 

*Total sheep and lamb death losses for 1994 have been revised, although the revisions are not shown 

further in this publication since detailed cause of loss estimates were not similarly adjusted and 

republished. Sheep losses were revised from 336.6 to 332.8 (thousand head), and lamb losses were 

revised from 609.4 to 614.7; as a result, total losses were revised from 946.0 to 947.5 thousand head. 

Total sheep and lamb death losses for 1999 were revised from 260,900 to 259,800 sheep lost and from 

482,000 to 488,600 lambs lost. Since the predator loss publication was not reissued, adjustments 

(reflecting the revised total sheep and total lamb losses) were made appropriately to the nonpredator loss 

category. 
USDA APHIS VS / 11

Section I: Population Estimates, Number of Head

c. Number of lamb death losses by cause and percentage of loss by cause—by

year:

 Number and Percent Loss 

 Year 

 1994 1999 2004 

Cause Number Percent Number Percent Number Percent 

Nonpredator 347,925 57.1 289,300 59.2 227,200 59.0 

Predator 261,475 42.9 199,300* 40.8 157,800 41.0 

Total 609,400 100.0 488,600 100.0 385,000 100.0 

*Initial NASS publication showed predator lamb losses of 196,000 head. Subsequent publication only revised 

total lamb loss. Relationship between predator and nonpredator loss was maintained at the State level, 

therefore deriving 199,300 head lost due to predators in the United States. 
Section I: Population Estimates, Number of Head

12 / Sheep Death Loss, 2004

3. Regional predator and nonpredator death loss—1994, 1999, and 2004

Total sheep losses declined from 1994 to 2004 in every region except the

Southeast/Other. This decline probably reflects regional population changes,

since the percentage of sheep inventory lost has remained stable (tables B. 1a

and C. 1b). In every region, nonpredator losses of sheep were higher than

predator losses. For the West Central region in 2004, 41,500 sheep (39.2

percent of all sheep losses) were lost to predators, as compared to the Central

region where only 9,300 sheep (17.5 percent of all sheep losses) were lost to

predators. Surprisingly, the Southeast/Other region encountered a relatively high

percentage of losses due to predators (34.0 percent). Note that for the Pacific

and West Central regions, losses that occurred before docking were not included

in the estimates; for the other regions, losses before docking were included in

the estimates. While difficult to measure accurately, these losses may account

for a substantial portion of total losses. For discussion of predocking losses, see

Appendix.
USDA APHIS VS / 13

Section I: Population Estimates, Number of Head

 Number and Percent Loss 

 Year 

 1994 1999 2004 

Region Cause Number Percent Number Percent Number Percent 

Nonpredator 25,625 64.1 17,700 61.0 18,300 70.4 

Pacific Predator 14,375 35.9 11,300 39.0 7,700 29.6 

Total 40,000 100.0 29,000 100.0 26,000 100.0 

Nonpredator 116,325 62.2 87,500 66.8 64,500 60.8 

Predator 70,675 37.8 43,500 33.2 41,500 39.2 West 

Central 

Total 187,000 100.0 131,000 100.0 106,000 100.0 

Nonpredator 59,800 83.2 54,900 81.9 43,700 82.5 

Central Predator 12,100 16.8 12,100 18.1 9,300 17.5 

Total 71,900 100.0 67,000 100.0 53,000 100.0 

Nonpredator 21,875 76.1 15,900 80.3 15,600 78.0 

Northeast Predator 6,875 23.9 3,900 19.7 4,400 22.0 

Total 28,750 100.0 19,800 100.0 20,000 100.0 

Nonpredator 6,400 71.5 7,400 56.9 6,800 66.0 

Predator 2,550 28.5 5,600 43.1 3,500 34.0 Southeast/

Other 

Total 8,950 100.0 13,000 100.0 10,300 100.0 

a. Number of sheep death losses by cause and percentage of loss by cause—by

region and by year:
Section I: Population Estimates, Number of Head

14 / Sheep Death Loss, 2004
USDA APHIS VS / 15

Section I: Population Estimates, Number of Head

In the Pacific and West Central regions, the percentage of loss due to predators

was higher for lambs (67.6 and 66.7 percent, respectively) than for sheep (29.6

and 39.2 percent, respectively) (table 3. a). The percentages of predator and

nonpredator sheep losses in these regions (approximately one-third predator and

two-thirds nonpredator) are nearly reversed for lamb losses (approximately twothirds predator and one-third nonpredator). The highest percentage of lamb loss

due to nonpredator causes occurred in the Central and Northeast regions (84.1

and 80.5 percent, respectively).

b. Number of lamb death losses by cause and percentage of loss by cause—by

region and by year:

 Number and Percent Loss 

 Year 

 1994 1999 2004 

Region Cause Number Percent Number Percent Number Percent 

Nonpredator 18,825 39.2 11,200 37.3 6,800 32.4 

Pacific Predator 29,175 60.8 18,800 62.7 14,200 67.6 

Total 48,000 100.0 30,000 100.0 21,000 100.0 

Nonpredator 108,525 36.9 97,300 42.1 53,000 33.3 

Predator 185,475 63.1 133,700 57.9 106,000 66.7 West 

Central 

Total 294,000 100.0 231,000 100.0 159,000 100.0 

Nonpredator 156,175 83.7 132,700 81.2 117,300 84.1 

Central Predator 30,525 16.3 30,800 18.8 22,200 15.9 

Total 186,700 100.0 163,500 100.0 139,500 100.0 

Nonpredator 50,000 81.9 35,700 81.0 36,300 80.5 

Northeast Predator 11,050 18.1 8,400 19.0 8,800 19.5 

Total 61,050 100.0 44,100 100.0 45,100 100.0 

Nonpredator 14,400 73.3 12,400 62.0 13,800 67.6 

Predator 5,250 26.7 7,600 38.0 6,600 32.4 Southeast/

Other 

Total 19,650 100.0 20,000 100.0 20,400 100.0 
Section I: Population Estimates, Number of Head

16 / Sheep Death Loss, 2004
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 17

Section II: Population Estimates—Nonpredator Losses

A. Nonpredator

Sheep Death Loss

1. Losses—2004

Nonpredator sheep death loss accounted for 3.9 percent of adult sheep

inventory losses. Overall, the percentage of loss was slightly higher on

operations with fewer than 100 sheep and lambs compared to operations with

100 or more sheep and lambs.

a. Sheep death loss as a percentage of adult sheep inventory on January 1,

2000, by size of operation and by region:*

Percent Inventory 

Size of Operation (Number of Sheep and Lambs)

1–24 25–99 100–999 

1,000 

or More 

All 

Operations 

Region Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Pacific 5.9 (1.0) 5.0 (1.1) 4.0 (0.4) 3.3 (0.3) 4.0 (0.3) 

West 

Central 5.9 (1.1) 7.1 (1.6) 3.0 (0.1) 2.0 (0.1) 2.8 (0.2) 

Central 6.3 (0.8) 4.8 (0.3) 4.1 (0.1) 4.2 (0.3) 4.6 (0.1) 

Northeast 4.1 (0.7) 4.2 (0.6) 4.6 (0.3) 1.8 (0.3) 4.2 (0.8) 

Southeast/ 

Other 7.2 (1.7) 3.4 (0.5) 4.2 (0.2) 9.0 (0.0) 5.1 (0.5) 

All 

operations 5.7 (0.4) 5.0 (0.4) 3.6 (0.1) 2.4 (0.1) 3.9** 

*2004 nonpredator death loss divided by the following January 1, 2005, inventory of ewes and rams 

for breeding 1 year or older, and market sheep. 

**No standard error available. 
Section II: Population Estimates, Nonpredator Losses

18 / Sheep Death Loss, 2004

2. Cause of loss—1994, 1999, and 2004*

“Other” nonpredator causes of loss (such as old age, lameness, and being on

back) accounted for more losses than any other category in 1994 and 1999

(34.7 percent and 34.0 percent of losses, respectively). In 2004, old age and

being on back were removed from the “other” category. In 2004, old age

accounted for more sheep losses than any other cause (26.8 percent of

losses). Theft and weather-related causes were lower in 2004 than in 1994.

The percentage of loss due to unknown causes appears to be decreasing,

which is good news for producers and veterinarians alike.

a. Percentage of sheep death loss by cause and by year:

Percent Nonpredator Loss 

Nonpredator Cause 1994 1999 2004 

Digestive problems (bloat, scours, 

parasites, enterotoxemia, acidosis, etc.) 9.3 11.6 12.9 

Respiratory problems 

(pneumonia, shipping fever, etc.) 6.9 8.5 9.4 

Metabolic problems (milk fever, twin 

lamb disease, pregnancy toxemia, etc.) 3.6 3.2 3.7 

Weather-related causes 

(chilling, drowning, lightning, etc.) 8.4 6.7 3.9 

Theft (stolen) 2.0 0.8 0.5 

Poisoning (nitrate poisoning, 

noxious feeds, noxious weeds, etc.) 5.3 4.0 3.9 

Lambing problems 9.9 11.3 13.4 

Old age N/A N/A 26.8 

Being on back N/A N/A 2.0 

Other diseases 

(mastitis, footrot, boils, etc.) N/A 5.6 6.6 

Other** 34.7 34.0 4.8 

Unknown 19.9 14.3 12.1 

Total 100.0 100.0 100.0 

*See Section III: Methodology. 

**Lameness, etc. (Includes old age and being on back in 1994 and 1999). 
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 19

The percentage of inventory lost due to all nonpredator causes remained

relatively constant from 1994 to 2004, at slightly less than 4 percent. The

percentage lost due to digestive, respiratory, and lambing problems increased.

Losses due to “other” causes declined in 2004, primarily due to removing “old

age” and “being on back” from that category.

b. Percentage of January 1 following-year adult sheep inventory lost, by cause

and by year:

Percent Inventory 

Nonpredator Cause 1994 1999 2004 

Digestive problems (bloat, 

scours, parasites, enterotoxemia, 

acidosis, etc.) 0.37 0.43 0.50 

Respiratory problems 

(pneumonia, shipping fever, etc.) 0.27 0.31 0.36 

Metabolic problems (milk fever, 

twin lamb disease, pregnancy 

toxemia, etc.) 0.14 0.12 0.14 

Weather-related causes 

(chilling, drowning, lightning, etc.) 0.34 0.25 0.15 

Theft (stolen) 0.08 0.03 0.02 

Poisoning (nitrate poisoning, 

noxious feeds, noxious weeds, etc.) 0.21 0.15 0.15 

Lambing problems 0.39 0.42 0.52 

Old age N/A N/A 1.04 

Being on back N/A N/A 0.08 

Other diseases 

(mastitis, footrot, boils, etc.) N/A 0.21 0.26 

Other** 1.39 1.26 0.19 

Unknown 0.79 0.53 0.47 

All nonpredator causes 3.99 3.70 3.88 

* See Section III: Methodology. 

**Lameness, etc. (Includes old age and being on back in 1994 and 1999). 
Section II: Population Estimates, Nonpredator Losses

20 / Sheep Death Loss, 2004

3. Cause of loss by size of operation—2004

While the percentages of nonpredator losses were similar across all operation

sizes for most causes of loss, operations with 1,000 or more sheep and lambs

reported a higher percentage of loss due to poisoning (8.0 percent) and a lower

percentage of loss due to old age (17.4 percent) compared to the other

operation sizes.

a. Percentage of sheep death loss by cause and by size of operation:

Percent Nonpredator Loss 

Size of Operation (Number of Sheep and Lambs) 

1-24 25-99 100-999 1,000 or 

More 

Nonpredator Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems 

(bloat, scours, parasites, 

enterotoxemia, acidosis, 

etc.) 10.6 (2.1) 14.7 (3.4) 16.8 (1.9) 9.7 (1.3) 

Respiratory problems 

(pneumonia, shipping 

fever, etc.) 7.2 (2.3) 7.0 (1.3) 10.0 (0.9) 10.5 (1.2) 

Metabolic problems (milk 

fever, twin lamb disease, 

pregnancy toxemia, etc.) 1.9 (0.6) 2.7 (0.8) 3.5 (0.3) 4.7 (1.0) 

Weather-related causes 

(chilling, drowning, 

lightning, etc.) 2.7 (0.9) 3.0 (0.8) 4.8 (1.3) 3.3 (0.4) 

Theft (stolen) 0.0 (0.0) 0.0 (0.0) 0.3 (0.2) 0.8 (0.2) 

Poisoning (nitrate 

poisoning, noxious feeds, 

noxious weeds, etc.) 2.4 (0.9) 1.1 (0.3) 2.3 (0.3) 8.0 (0.9) 

Lambing problems 13.3 (1.9) 15.2 (2.1) 10.9 (0.8) 13.8 (1.3) 

Old age 34.0 (3.2) 30.0 (3.3) 29.8 (1.2) 17.4 (1.3) 

Being on back 0.7 (0.3) 1.2 (0.4) 1.9 (0.2 2.8 (0.2) 

Other diseases (mastitis, 

footrot, boils, etc.) 5.9 (1.7) 6.9 (3.3) 5.1 (0.4) 8.1 (1.4) 

Other * 4.5 (1.1) 7.3 (2.0) 4.6 (0.7) 4.6 (0.6) 

Unknown 16.8 (3.0) 10.9 (1.5) 10.0 (0.7) 16.3 (1.2) 

Total 100.0 100.0 100.0 100.0 

*Lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 21

Operations with 1,000 or more sheep and lambs lost a lower percentage of

inventory due to digestive causes (0.2 percent) compared to operations with 1

to 24, 25 to 99, and 100 to 999 sheep and lambs (0.60 percent, 0.74 percent,

and 0.61 percent, respectively). Old age accounted for the highest percentage

of loss on all operations. However, on operations with 1,000 head, the

percentage of loss due to old age (0.42 percent of inventory) was similar to the

percentage of loss due to unknown causes or lambing problems (0.39 percent

and 0.33 percent, respectively).

b. Percentage of January 1 following-year adult sheep inventory lost, by cause

and by size of operation:

Percent Inventory 

Size of Operation (Number of Sheep and Lambs) 

1-24 25-99 100-999 1,000 or 

More 

Nonpredator 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems 

(bloat, scours, parasites, 

enterotoxemia, acidosis, 

etc.) 0.60 (0.13) 0.74 (0.21) 0.61 (0.08) 0.23 (0.03) 

Respiratory problems 

(pneumonia, shipping 

fever, etc.) 0.41 (0.14) 0.35 (0.06) 0.36 (0.03) 0.25 (0.03) 

Metabolic problems (milk 

fever, twin lamb disease, 

pregnancy toxemia, etc.) 0.11 (0.03) 0.14 (0.04) 0.13 (0.01) 0.11 (0.03) 

Weather-related causes 

(chilling, drowning, 

lightning, etc.) 0.15 (0.05) 0.15 (0.04) 0.17 (0.05) 0.08 (0.01) 

Theft (stolen) 0.00 (0.00) 0.00 (0.00) 0.01 (0.01) 0.02 (0.00) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious weeds, 

etc.) 0.14 (0.05) 0.05 (0.01) 0.08 (0.01) 0.19 (0.02) 

Lambing problems 0.75 (0.11) 0.77 (0.09) 0.40 (0.03) 0.33 (0.04) 

Old age 1.92 (0.22) 1.51 (0.14) 1.08 (0.05) 0.42 (0.03) 

Being on back 0.04 (0.02) 0.06 (0.02) 0.07 (0.01) 0.07 (0.01) 

Other diseases (mastitis, 

footrot, boils, etc.) 0.34 (0.10) 0.35 (0.19) 0.18 (0.02) 0.20 (0.04) 

Other * 0.25 (0.06) 0.37 (0.10) 0.17 (0.03) 0.11 (0.02) 

Unknown 0.95 (0.19) 0.55 (0.07) 0.36 (0.03) 0.39 (0.02) 

All nonpredator causes 5.66 (0.43) 5.04 (0.40) 3.62 (0.10) 2.40 (0.10) 

*Lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

22 / Sheep Death Loss, 2004

4. Cause of loss by region—2004

The percentage of losses due to old age ranged from 18.7 percent of losses in

the Southeast/Other region to 31.9 percent in the Pacific region. Losses due to

unknown causes ranged from 8.6 percent of losses in the Pacific region to 30.3

percent in the Southeast/Other region.

a. Percentage of sheep death loss by cause and by region:

Percent Nonpredator Loss 

Region 

 Pacific 

West 

Central Central Northeast 

Southeast/ 

Other 

Nonpredator Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems 

(bloat, scours, 

parasites, 

enterotoxemia, 

acidosis, etc.) 9.9 (3.1) 15.6 (2.3) 11.7 (0.9) 10.7 (1.4) 21.2 (9.4) 

Respiratory problems 

(pneumonia, shipping 

fever, etc.) 11.7 (2.4) 6.4 (1.1) 12.2 (1.1) 6.7 (1.2) 5.1 (2.1) 

Metabolic problems 

(milk fever, twin lamb 

disease, pregnancy 

toxemia, etc.) 2.7 (0.6) 3.7 (0.8) 3.5 (0.6) 3.7 (1.0) 1.4 (0.6) 

Weather-related 

causes (chilling, 

drowning, lightning, 

etc.) 2.4 (1.4) 3.4 (0.4) 4.5 (1.3) 3.5 (0.9) 2.0 (0.7) 

Theft (stolen) 0.3 (0.1) 0.5 (0.1) 0.2 (0.1) 0.0 (0.0) 0.7 (0.5) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious weeds, 

etc.) 3.4 (1.4) 6.0 (0.6) 1.5 (0.3) 2.3 (1.0) 0.3 (0.2) 

Lambing problems 7.4 (1.4) 12.8 (1.4) 15.2 (1.0) 17.0 (2.1) 11.6 (5.3) 

Old age 31.9 (4.0) 22.6 (1.7) 30.8 (1.4) 31.0 (2.9) 18.7 (4.2) 

Being on back 1.7 (0.3) 2.5 (0.3) 1.1 (0.1) 2.0 (0.5) 0.3 (0.1) 

Other diseases 

(mastitis, footrot, 

boils, etc.) 8.3 (2.8) 8.6 (2.2) 4.1 (0.5) 5.7 (2.2) 3.4 (1.0) 

Other * 11.7 (3.8) 4.3 (0.6) 4.0 (0.5) 4.6 (1.0) 5.0 (1.2) 

Unknown 8.6 (1.7) 13.6 (1.1) 11.2 (1.2) 12.8 (1.6) 30.3 (6.7) 

Total 100.0 100.0 100.0 100.0 100.0 

*Lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 23

Percent Inventory 

Region 

Pacific 

West 

Central Central Northeast 

Southeast/ 

Other 

Nonpredator Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems 

(bloat, scours, 

parasites, enterotoxemia, acidosis, 

etc.) 0.39 (0.12) 0.43 (0.08) 0.54 (0.04) 0.45 (0.07) 1.08 (0.46) 

Respiratory problems 

(pneumonia, shipping 

fever, etc.) 0.47 (0.10) 0.18 (0.03) 0.56 (0.05) 0.28 (0.06) 0.26 (0.11) 

Metabolic problems 

(milk fever, twin lamb 

disease, pregnancy 

toxemia, etc.) 0.11 (0.02) 0.10 (0.02) 0.16 (0.03) 0.16 (0.04) 0.07 (0.03) 

Weather-related 

causes (chilling, 

drowning, lightning, 

etc.) 0.10 (0.05) 0.09 (0.01) 0.20 (0.06) 0.15 (0.04) 0.10 (0.03) 

Theft (stolen) 0.01 (0.00) 0.01 (0.00) 0.01 (0.01) 0.00 (0.00) 0.04 (0.03) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious 

weeds, etc.) 0.13 (0.06) 0.17 (0.01) 0.07 (0.01) 0.10 (0.04) 0.02 (0.01) 

Lambing problems 0.30 (0.06) 0.36 (0.04) 0.70 (0.05) 0.71 (0.10) 0.59 (0.27) 

Old age 1.27 (0.18) 0.63 (0.04) 1.42 (0.07) 1.30 (0.16) 0.95 (0.22) 

Being on back 0.07 (0.01) 0.07 (0.01) 0.05 (0.01) 0.08 (0.02 0.01 (0.01) 

Other diseases 

(mastitis, footrot, 

boils, etc.) 0.33 (0.12) 0.24 (0.07) 0.19 (0.02) 0.24 (0.10) 0.17 (0.05) 

Other* 0.46 (0.16) 0.12 (0.02) 0.19 (0.02) 0.19 (0.04) 0.25 (0.06) 

Unknown 0.34 (0.07) 0.38 (0.02) 0.52 (0.06) 0.53 (0.08) 1.54 (0.43) 

All nonpredator 

causes 3.98 (0.26) 2.77 (0.16) 4.61 (0.14) 4.19 (0.32) 5.08 (0.46) 

*Lameness, etc.

The percentage of sheep inventory lost to unknown nonpredator causes ranged

from 1.54 percent in the Southeast/Other region to 0.34 percent in the Pacific

region. A higher percentage of adult sheep inventory was lost to nonpredator

causes in the Southeast/Other region than in the West Central region (5.08

percent and 2.77 percent, respectively).

b. Percentage of January 1 following-year adult sheep inventory lost, by cause

and by region:
Section II: Population Estimates, Nonpredator Losses

24 / Sheep Death Loss, 2004

5. Cause of loss by region and by size of operation—2004

In the Pacific region, old age accounted for a higher percentage of sheep death

loss than any other reported cause of loss.

a. For the Pacific region, percentage of sheep death loss by cause and by size

of operation:

Percent Nonpredator Loss 

Size of Operation (Number of Sheep and Lambs)

1–24 25–99 100–999 

1,000 

or More 

All 

Operations 

Nonpredator Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems 

(bloat, scours, 

parasites, 

enterotoxemia, 

acidosis, etc.) 14.0 (9.6) 3.1 (1.4) 7.3 (2.3) 12.1 (5.1) 9.9 (3.1) 

Respiratory 

problems 

(pneumonia, 

shipping fever, etc.) 6.7 (3.8) 1.0 (0.5) 9.3 (1.9) 18.5 (4.1) 11.7 (2.3) 

Metabolic problems 

(milk fever, twin lamb 

disease, pregnancy 

toxemia, etc.) 0.8 (0.7) 3.8 (2.2) 6.3 (1.6) 1.7 (0.5) 2.7 (0.6) 

Weather-related 

causes (chilling, 

drowning, 

lightning, etc.) 0.0 (0.0) 7.9 (6.8) 0.9 (0.2) 1.6 (0.7) 2.4 (1.4) 

Theft (stolen) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.5 (0.2) 0.3 (0.1) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious 

weeds, etc.) 1.6 (1.6) 0.5 (0.3) 0.9 (0.4) 5.9 (2.9) 3.4 (1.4) 

Lambing problems 8.6 (3.2) 8.0 (3.3) 9.1 (1.3) 6.3 (2.5) 7.4 (1.4) 

Old age 30.4 (7.1) 41.0 (14.4) 36.4 (4.3) 27.2 (4.8) 31.9 (4.0) 

Being on back 0.1 (0.1 0.4 (0.2) 2.4 (0.5) 2.5 (0.6) 1.7 (0.3) 

Other diseases 

(mastitis, footrot, 

boils, etc.) 2.4 (2.4) 2.8 (1.5) 3.2 (0.7) 14.2 (5.6) 8.3 (2.8) 

Other* 10.8 (5.2) 23.5 (14.9) 15.1 (7.8) 6.1 (2.3) 11.7 (3.8) 

Unknown 24.6 (7.5) 8.0 (3.3) 9.1 (1.6) 3.4 (1.1) 8.6 (1.7) 

Total 100.0 100.0 100.0 100.0 100.0 

*Lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 25

In the West Central region, old age accounted for a higher percentage of

nonpredator losses on operations with 1 to 24 sheep and lambs than on

operations with 1,000 or more sheep and lambs (38.0 percent and 14.2 percent,

respectively).

b. For the West Central region, percentage of sheep death loss by cause and

by size of operation:

Percent Nonpredator Loss 

Size of Operation (Number of Sheep and Lambs)

 1–24 25–99 100–999 

1,000 

or More 

All 

Operations 

Nonpredator 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems, 

bloat, scours, 

parasites, 

enterotoxemia, 

acidosis, etc.) 10.2 (4.7) 27.9 (8.3) 18.6 (2.2) 8.9 (0.7) 15.6 (2.3) 

Respiratory 

problems 

(pneumonia, 

shipping fever, etc.) 18.0 (10.8) 2.2 (1.0) 6.6 (1.7) 6.3 (0.5) 6.4 (1.1) 

Metabolic problems 

(milk fever, twin lamb

disease, pregnancy 

toxemia, etc.) 2.7 (1.7) 0.9 (0.5) 2.7 (0.5) 5.8 (1.5) 3.7 (0.8) 

Weather-related 

causes (chilling, 

drowning, 

lightning, etc.) 3.8 (2.7) 1.1 (0.5) 4.4 (0.9) 3.8 (0.5) 3.4 (0.4) 

Theft (stolen) 0.0 (0.0) 0.1 (0.1) 0.2 (0.1) 0.9 (0.3) 0.5 (0.1) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious 

weeds, etc.) 3.2 (2.6) 1.6 (0.7) 3.5 (0.4) 10.3 (1.0) 6.0 (0.6) 

Lambing problems 11.7 (6.8) 10.7 (4.7) 7.1 (0.6) 17.9 (1.7) 12.8 (1.4) 

Old age 38.0 (9.3) 20.7 (6.6) 32.3 (1.8) 14.2 (0.9) 22.6 (1.7) 

Being on back 0.9 (0.4) 2.3 (1.4) 2.3 (0.2) 2.9 (0.3) 2.5 (0.3) 

Other diseases 

(mastitis, footrot, 

boils, etc.) 5.6 (2.5) 16.9 (8.9) 7.3 (0.9) 6.2 (0.5) 8.6 (2.2) 

Other* 0.7 (0.4) 6.6 (2.8) 3.7 (0.8) 4.3 (0.5) 4.3 (0.6) 

Unknown 5.2 (2.0) 9.0 (3.0) 11.3 (1.4) 18.5 (1.5) 13.6 (1.1) 

Total 100.0 100.0 100.0 100.0 100.0 

*Lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

26 / Sheep Death Loss, 2004

In the Central region, the percentage of sheep death losses due to respiratory

problems was lower on operations with 1 to 24 sheep and lambs (3.3 percent)

than on operations with 25 to 99, 100 to 999, and 1,000 or more sheep and

lambs (12.0 percent, 14.5 percent, and 20.5 percent, respectively). Sheep death

loss due to old age was higher than any other cause of loss for all operations

with fewer than 1,000 head. On operations with 1,000 or more head, respiratory

problems and old age accounted for the highest percentages of nonpredator

losses (20.5 percent and 19.5 percent, respectively).

c. For the Central region, percentage of sheep death loss by cause and by size

of operation:

Percent Nonpredator Loss 

Size of Operation (Number of Sheep and Lambs)

1–24 25–99 100–999 

1,000 

or More 

All 

Operations 

Nonpredator Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems 

(bloat, scours, 

parasites, 

enterotoxemia, 

acidosis, etc.) 12.9 (3.3) 9.4 (1.5) 13.2 (1.1) 11.1 (1.3) 11.7 (0.9)

Respiratory 

problems 

(pneumonia, 

shipping fever, etc.) 3.3 (1.0) 12.0 (2.5) 14.5 (1.3) 20.5 (3.3) 12.2 (1.1)

Metabolic problems 

(milk fever, twin 

lamb disease, 

pregnancy toxemia, 

etc.) 1.8 (1.0) 3.2 (1.6) 3.9 (0.6) 6.2 (1.4) 3.5 (0.6)

Weather-related 

causes (chilling, 

drowning, 

lightning, etc.) 4.5 (2.0) 2.3 (0.6) 6.1 (3.0) 4.6 (0.6) 4.5 (1.3)

Theft (stolen) 0.0 (0.0) 0.0 (0.0) 0.3 (0.3) 0.7 (0.3) 0.2 (0.1)

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious 

weeds, etc.) 1.8 (1.1) 1.3 (0.5) 1.5 (0.3) 1.4 (0.4) 1.5 (0.3)

Lambing problems 17.9 (3.1) 16.4 (1.8) 14.0 (1.5) 11.0 (1.1) 15.2 (1.0)

Old age 32.8 (4.5) 33.9 (2.8) 29.9 (1.7) 19.5 (2.0) 30.8 (1.4)

Being on back 0.4 (0.3) 0.9 (0.3) 1.1 (0.2) 3.5 (0.5) 1.1 (0.1)

Other diseases 4.9 (1.8) 3.1 (0.8) 3.7 (0.4) 7.7 (1.0) 4.1 (0.5)

Other* 4.3 (1.4) 5.2 (1.1) 3.1 (0.5) 3.6 (1.1) 4.0 (0.5)

Unknown 15.4 (3.9) 12.3 (2.5) 8.7 (1.0) 10.2 (1.7) 11.2 (1.2)

Total 100.0 100.0 100.0 100.0 100.0 

*Lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 27

In the Northeast region, only 3.1 percent of losses on operations with 1,000 or

more sheep and lambs was due to old age, compared to 23.1 percent, 32.0

percent, and 37.9 percent of losses for operations with 100 to 999, 25 to 99, and

1 to 24 sheep and lambs, respectively).

d. For the Northeast region, percentage of sheep death loss by cause and by

size of operation:

Percent Nonpredator Loss 

Size of Operation (Number of Sheep and Lambs) 

1–24 25–99 100–999 

1,000 

or More 

All 

Operations 

Nonpredator 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems 

(bloat, scours, 

parasites, 

enterotoxemia, 

acidosis, etc.) 5.7 (2.2) 11.2 (2.6) 14.5 (1.9) 28.4 (5.8) 10.7 (1.4)

Respiratory problems 

(pneumonia, shipping 

fever, etc.) 4.6 (2.0) 7.1 (2.3) 8.3 (1.5) 10.9 (4.6) 6.7 (1.2)

Metabolic problems 

(milk fever, twin lamb 

disease, pregnancy 

toxemia, etc.) 2.2 (1.1) 4.8 (2.0) 3.8 (1.0) 2.6 (0.8) 3.7 (0.9)

Weather-related 

causes (chilling, 

drowning, lightning, 

etc.) 0.5 (0.5) 4.9 (1.7) 4.5 (1.5) 1.8 (1.0) 3.5 (0.9)

Theft (stolen) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious 

weeds, etc.) 4.8 (2.8) 0.4 (0.3) 2.7 (2.0) 0.0 (0.0) 2.3 (1.0)

Lambing problems 14.0 (3.1) 18.8 (3.6) 17.7 (3.7) 8.1 (2.7) 17.0 (2.1)

Old age 37.9 (7.0) 32.0 (4.2) 23.1 (2.6) 3.1 (0.6) 31.0 (2.9)

Being on back 1.9 (1.4) 0.5 (0.2) 4.0 (1.1) 10.2 (1.6) 2.0 (0.5)

Other diseases 

(mastitis, footrot, 

boils, etc.) 12.5 (6.6) 2.4 (1.2) 3.7 (0.8) 2.0 (0.8) 5.7 (2.2)

Other* 3.8 (2.1) 4.2 (1.6) 5.1 (1.4) 29.0 (7.2) 4.6 (1.0)

Unknown 12.1 (3.6) 13.7 (2.6) 12.6 (2.1) 3.9 (0.7) 12.8 (1.6)

Total 100.0 100.0 100.0 100.0 100.0 

*Lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

28 / Sheep Death Loss, 2004

In the Southeast/Other region, the percentage of losses due to digestive

causes ranged from 7.8 percent on operations with 1 to 24 sheep and lambs to

52.0 percent on operations with 100 to 999 sheep and lambs. The percentage

of losses due to unknown causes tended to decrease as operation size

increased, although the differences were not statistically significant.

e. For the Southeast/Other region, percentage of sheep death loss by cause

and by size of operation:

Percent Nonpredator Loss 

Size of Operation (Number of Sheep and Lambs)

1–24 25–99 100–999 

1,000 

or More* 

All 

Operations 

Nonpredator Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems 

(bloat, scours, 

parasites, 

enterotoxemia, 

acidosis, etc.) 7.8 (3.3) 17.3 (5.4) 52.0 (19.8) 21.2 (9.4) 

Respiratory problems 

(pneumonia, shipping 

fever, etc.) 8.2 (5.6) 6.0 (2.4) 3.2 (1.5) 5.1 (2.1) 

Metabolic problems 

(milk fever, twin lamb 

disease, pregnancy 

toxemia, etc.) 2.2 (1.6) 0.9 (0.3) 1.5 (0.7) 1.4 (0.6) 

Weather-related causes 

(chilling, drowning, 

lightning, etc.) 2.6 (1.6) 2.1 (1.2) 2.5 (1.2) 2.0 (0.7) 

Theft (stolen) 0.4 (0.4) 0.0 (0.0) 2.1 (2.0) 0.7 (0.5) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious 

weeds, etc.) 0.0 (0.0) 0.0 (0.0) 1.3 (0.8) 0.3 (0.2) 

Lambing problems 6.5 (3.0) 35.7 (16.4) 4.9 (2.1) 11.6 (5.3) 

Old age 29.4 (9.9) 21.9 (7.5) 12.1 (5.2) 18.7 (4.2) 

Being on back 0.0 (--) 0.7 (0.5) 0.4 (0.2) 0.3 (0.1) 

Other diseases 

(mastitis, footrot, 

boils, etc.) 2.6 (2.3) 3.0 (1.2) 5.2 (2.2) 3.4 (0.9) 

Other** 4.0 (2.4) 5.8 (2.0) 8.3 (3.7) 5.0 (1.2) 

Unknown 36.3 (14.6) 6.6 (2.2) 6.5 (3.1) 30.3 (6.7) 

Total 100.0 100.0 100.0 100.0 

*Too few operations to report. 

**Lameness, etc.
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 29

B. Nonpredator

Lamb Death Loss

1. Losses—2004

This section addresses postdocking losses only in the Pacific and West Central

regions. Due to the way sheep are managed in these regions, predocking losses

are difficult for producers to quantify accurately. However, a substantial amount

of loss likely occurs before docking. For a discussion of predocking losses, see

Appendix.

Operations with 1 to 24 sheep and lambs lost the highest percentage of lamb

crop (10.9 percent) due to nonpredator causes than any other operation size.

Overall, as the size of operation increased the percentage of lamb crop lost

decreased. The Pacific and West Central regions lost a significantly lower

percentage of lamb crop (1.4 percent and 2.4 percent, respectively) than the

Central, Northeast, and Southeast/Other regions (9.5 percent, 9.8 percent, and

10.5 percent, respectively). However, loss estimates for the Pacific and West

Central regions were made after tail-docking, while estimates for the Central,

Northeast, and Southeast regions were made from birth, which may explain the

difference.

a. Percentage of lamb crop lost*, by size of operation and by region:

Percent Lamb Crop 

Size of Operation (Number of Sheep and Lambs)

1–24 25–99 100–999 

1,000 

or More 

All 

Operations 

Region Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

 

Pacific 1.5 (0.4) 1.4 (0.42 2.2 (0.1) 1.1 (0.1) 1.4 (0.1) 

West 

Central 3.9 (1.0) 3.0 (0.4) 2.3 (0.1) 2.3 (0.1) 2.4 (0.1) 

Central 16.2 (1.6) 9.9 (0.6) 7.4 (0.2) 10.2 (0.1) 9.5 (0.3) 

Northeast 9.3 (1.2) 10.6 (1.7) 9.2 (0.8) 7.4 (0.8) 9.8 (0.8) 

Southeast/

Other 15.2 (1.6) 8.4 (2.3) 10.0 (1.4) 7.7 (0.0) 10.5 (1.1) 

All 

operations 10.9 (0.8) 8.2 (0.5) 5.4 (0.2) 2.7 (0.1) 5.5** 

*2004 nonpredator lamb death loss divided by 1999 lamb crop x 100. Includes postdocking lamb losses only in 

the Pacific and West Central regions. 

**No standard error available. 
Section II: Population Estimates, Nonpredator Losses

30 / Sheep Death Loss, 2004
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 31

2. Cause of loss—1994, 1999, and 2004*

From 1994 to 2004, the causes of lamb crop losses remained fairly consistent.

Digestive and respiratory losses represented the highest percentages of loss in

1994, 1999, and 2004.

a. Percentage of lamb death loss by cause and by year:

Percent Nonpredator Loss 

 1994 1999 2004 

Nonpredator Cause Percent Percent Percent 

Digestive problems (bloat, 

scours, parasites, 

enterotoxemia, acidosis, etc.) 19.3 17.4 19.8 

Respiratory problems 

(pneumonia, shipping fever, 

etc.) 19.4 21.9 22.8 

Metabolic problems (milk fever, 

twin lamb disease, pregnancy 

toxemia, etc.) 3.9 3.2 2.8 

Weather-related causes 

(chilling, drowning, lightning, 

etc.) 16.9 12.8 14.8 

Theft (stolen) 1.8 0.9 0.7 

Poisoning (nitrate poisoning, 

noxious feeds, noxious weeds, 

etc.) 2.5 1.8 2.0 

Lambing problems** 10.5 10.4 14.7 

Other diseases (mastitis, 

footrot, boils, etc.) N/A 3.8 3.3 

Other*** 8.2 13.1 5.8 

Unknown 17.5 14.7 13.3 

Total 100.0 100.0 100.0 

* See Section III: Methodology 

**Does not include Pacific and West Central regions. 

***Being on back, lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

32 / Sheep Death Loss, 2004

b. Percentage of lamb crop lost by cause and by year:

Percent Lamb Crop 

 1994 1999 2004 

Nonpredator Cause Percent Percent Percent 

Digestive problems (bloat, scours, 

parasites, enterotoxemia, acidosis, 

etc.) 1.12 0.97 1.10 

Respiratory problems (pneumonia, 

shipping fever, etc.) 1.13 1.21 1.26 

Metabolic problems (milk fever, twin 

lamb disease, pregnancy toxemia, 

etc.) 0.23 0.18 0.15 

Weather-related causes (chilling, 

drowning, lightning, etc.) 0.98 0.71 0.82 

Theft (stolen) 0.11 0.05 0.04 

Poisoning (nitrate poisoning, noxious 

feeds, noxious weeds, etc.) 0.15 0.10 0.11 

Lambing problems** 0.61 0.57 0.82 

Other diseases (mastitis, footrot, 

boils, etc.) N/A 0.21 0.19 

Other*** 0.48 0.73 0.32 

Unknown 1.02 0.82 0.74 

All nonpredator causes 5.83 5.55 5.55 

* See Section III: Methodology 

**Does not include Pacific and West Central regions. 

***Being on back, lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 33

3. Cause of loss by size of operation—2004

A higher percentage of lamb losses on operations with 1,000 or more sheep

and lambs was due to digestive causes (26.5 percent) compared to operations

with fewer than 100 sheep and lambs (less than 15 percent). Lambing

problems accounted for a significantly lower percentage of lamb losses (4.2

percent) on operations with 1,000 or more sheep and lambs compared to the

other operation sizes (at least 15 percent). The difference may reflect the fact

that losses due to lambing problems were not measured in the Pacific and

West Central regions where many of the largest operations exist. In addition,

losses as a result of lambing may be harder to observe on the largest

operations.

a. Percentage of lamb death loss by cause and by size of operation:

Percent Nonpredator Loss 

 Size of Operation (Number of Sheep and Lambs) 

 1-24 25-99 100-999 1,000 or 

More 

Nonpredator Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems (bloat, 

scours, parasites, 

enterotoxemia, acidosis, 

etc.) 12.9 (2.2) 14.9 (1.5) 23.8 (3.6) 26.5 (1.1) 

Respiratory problems 

(pneumonia, shipping 

fever, etc.) 17.6 (3.0) 19.5 (2.8) 23.3 (1.5) 26.7 (0.8) 

Metabolic problems (milk 

fever, twin lamb disease, 

pregnancy toxemia, etc.) 3.0 (1.1) 3.4 (0.7) 2.1 (0.3) 1.3 (0.2) 

Weather-related causes 

(chilling, drowning, 

lightning, etc.) 18.1 (2.3) 17.0 (1.9) 13.1 (1.1) 10.5 (0.8) 

Theft 1.0 (1.0) 0.5 (0.2) 0.6 (0.3) 0.7 (0.2) 

Poisoning (nitrate 

poisoning, noxious feeds, 

noxious weeds, etc.) 0.6 (0.3) 1.1 (0.5) 1.2 (0.2) 4.6 (0.5) 

Lambing problems* 16.0 (2.1) 21.7 (2.0) 15.2 (1.4) 4.2 (0.6) 

Other diseases (mastitis, 

footrot, boils, etc.) 2.6 (0.9) 2.8 (0.6) 2.7 (0.3) 3.5 (0.4) 

Other** 8.9 (1.9) 6.7 (1.1) 5.2 (0.4) 3.2 (0.3) 

Unknown 19.3 (5.0) 12.4 (1.3) 12.8 (1.0) 18.8 (1.1) 

Total 100.0 100.0 100.0 100.0 

*Does not include Pacific and West Central regions. 

**Being on back, lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

34 / Sheep Death Loss, 2004

As operation size increased, the percentage of lamb crop lost to digestive,

respiratory, metabolic, and lambing problems decreased.

b. Percentage of lamb crop lost by cause and by size of operation:

Percent Lamb Crop 

 Size of Operation (Number of Sheep and Lambs) 

 1-24 25-99 100-999 1,000 or More 

Nonpredator 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems 

(bloat, scours, 

parasites, 

enterotoxemia, 

acidosis, etc.) 1.41 (0.23) 1.22 (0.13) 1.28 (0.23) 0.72 (0.04) 

Respiratory 

problems 

(pneumonia, 

shipping fever, 

etc.) 1.91 (0.37) 1.60 (0.26) 1.27 (0.07) 0.73 (0.03) 

Metabolic 

problems (milk 

fever, twin lamb 

disease, 

pregnancy 

toxemia, etc.) 0.32 (0.12) 0.28 (0.06) 0.11 (0.02) 0.04 (0.01) 

Weather-related 

causes (chilling, 

drowning, 

lightning, etc.) 1.98 (0.28) 1.39 (0.19) 0.71 (0.06) 0.29 (0.02) 

Theft 0.11 (0.11) 0.04 (0.02) 0.03 (0.02) 0.02 (0.01) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious 

weeds, etc.) 0.06 (0.03) 0.09 (0.04) 0.07 (0.01) 0.13 (0.01) 

Lambing 

problems* 1.75 (0.21) 1.79 (0.20) 0.82 (0.07) 0.12 (0.02) 

Other diseases 

(mastitis, footrot, 

boils, etc.) 0.28 (0.10) 0.23 (0.05) 0.15 (0.02) 0.10 (0.01) 

Other** 0.97 (0.21) 0.55 (0.09) 0.28 (0.02) 0.09 (0.01) 

Unknown 2.10 (0.62) 1.02 (0.11) 0.69 (0.05) 0.51 (0.03) 

All nonpredator 

causes 10.89 (0.84) 8.21 (0.47) 5.41 (0.19) 2.75 (0.08) 

*Does not include Pacific and West Central regions. 

**Being on back, lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 35

4. Cause of loss by region—2004

The percentage of losses due to respiratory causes ranged from 30.8 percent in

the Pacific region to 9.5 percent in the Southeast/Other region. The percentage

of losses due to digestive problems ranged from 38.0 percent in the Southeast/

Other region to 14.4 percent in the Northeast region.

a. Percentage of all losses by cause and by region:

Percent Nonpredator Loss 

Region 

 Pacific 

West 

Central Central Northeast 

Southeast/

Other 

Nonpredator 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems 

(bloat, scours, 

parasites, 

enterotoxemia, 

acidosis, etc.) 19.6 (2.9) 27.9 (1.4) 16.0 (1.0) 14.4 (1.9) 38.0 (14.6) 

Respiratory 

problems 

(pneumonia, 

shipping fever, etc.) 30.8 (2.7) 20.5 (1.1) 25.1 (1.7) 15.4 (2.1) 9.5 (3.7) 

Metabolic problems 

(milk fever, twin 

lamb disease, 

pregnancy toxemia, 

etc.) 3.4 (1.1) 2.0 (0.3) 2.1 (0.3) 3.7 (1.0) 3.5 (2.6) 

Weather-related 

causes (chilling, 

drowning, 

lightning, etc.) 12.0 (3.7) 13.1 (1.1) 13.1 (0.9) 22.2 (2.8) 15.2 (5.0) 

Theft 0.9 (0.5) 2.2 (1.0) 0.2 (0.1) 0.6 (0.3) 0.0 (0.0) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious 

weeds, etc.) 2.2 (1.1) 5.2 (0.5) 0.8 (0.3) 1.1 (0.4) 0.0 (0.0) 

Lambing problems N/A N/A 20.9 (1.2) 19.3 (2.6) 12.6 (4.9) 

Other diseases 

(mastitis, footrot, 

boils, etc.) 3.7 (0.9) 3.4 (0.4) 3.2 (0.4) 1.3 (0.6) 1.8 (0.7) 

Other * 7.9 (2.2) 5.2 (0.6) 6.0 (0.8) 6.1 (1.1) 6.9 (2.9) 

Unknown 19.5 (3.2) 20.5 (1.2) 12.6 (1.8) 15.9 (2.0) 12.5 (3.5) 

Total 100.0 100.0 100.0 100.0 100.0 

*Being on back, lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

36 / Sheep Death Loss, 2004

The percentage of lamb crop lost to weather-related causes was significantly

higher in the Central, Northeast, and Southeast/Other regions (1.24 percent,

2.18 percent, and 1.60 percent, respectively) compared to the Pacific and West

Central regions (0.16 percent and 0.31 percent, respectively).

b. Percentage of lamb crop lost by cause and by region:

Percent Nonpredator Loss 

 Region 

Pacific 

West 

Central Central Northeast 

Southeast/ 

Other 

Nonpredator 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive 

problems (bloat, 

scours, parasites, 

enterotoxemia, 

acidosis, etc.) 0.27 (0.04) 0.68 (0.04) 1.52 (0.09) 1.41 (0.20) 3.99 (1.71) 

Respiratory 

problems 

(pneumonia, 

shipping fever, 

etc.) 0.42 (0.05) 0.49 (0.03) 2.41 (0.20) 1.51 (0.23) 0.99 (0.38) 

Metabolic 

problems (milk 

fever, twin lamb 

disease, 

pregnancy 

toxemia, etc.) 0.05 (0.02) 0.05 (0.01) 0.20 (0.03) 0.36 (0.10) 0.37 (0.28) 

Weather-related 

causes (chilling, 

drowning, 

lightning, etc.) 0.16 (0.06) 0.31 (0.03) 1.24 (0.09) 2.18 (0.38) 1.60 (0.51) 

Theft 0.01 (0.01) 0.05 (0.02) 0.02 (0.01) 0.06 (0.03) 0.00 (0.00) 

Poisoning (nitrate 

poisoning, 

noxious feeds, 

noxious weeds, 

etc.) 0.03 (0.02) 0.12 (0.01) 0.08 (0.03) 0.10 (0.04) 0.00 (0.00) 

Lambing 

problems N/A N/A 2.00 (0.10) 1.89 (0.34) 1.32 (0.52) 

Other diseases 

(mastitis, footrot, 

boils, etc.) 0.05 (0.01) 0.08 (0.01) 0.31 (0.04) 0.13 (0.05) 0.19 (0.07) 

Other* 0.11 (0.03) 0.12 (0.01) 0.57 (0.07) 0.60 (0.11) 0.72 (0.29) 

Unknown 0.27 (0.06) 0.49 (0.03) 1.20 (0.19) 1.56 (0.19) 1.31 (0.33) 

All nonpredator 

causes 1.37 (0.12) 2.39 (0.07) 9.55 (0.30) 9.80 (0.84) 10.49 (1.05) 

*Being on back, lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 37

5. Cause of loss by region and by size of operation—2004

In the Pacific region, as the size of operation increased the percentage of loss

due to metabolic and “other” causes of loss decreased.

a. For the Pacific region, percentage of lamb death loss by cause and by size

of operation:

Percent Nonpredator Loss 

Size of Operation (Number of Sheep and Lambs)

 1–24 25–99 100–999 

1,000 

or More 

All 

Operations 

Nonpredator 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive problems 

(bloat, scours, 

parasites, 

enterotoxemia, 

acidosis, etc.) 15.2 (9.4) 13.3 (6.8) 18.4 (2.5) 23.6 (5.3) 19.5 (2.9) 

Respiratory 

problems 

(pneumonia, 

shipping fever, 

etc.) 14.9 (9.2) 24.1 (6.1) 43.7 (3.7) 28.2 (4.0) 30.7 (2.7) 

Metabolic 

problems (milk 

fever, twin lamb 

disease, 

pregnancy 

toxemia, etc.) 13.5 (9.4) 7.4 (3.0) 2.2 (0.7) 0.6 (0.3) 3.4 (1.1) 

Weather-related 

causes (chilling, 

drowning, 

lightning, etc.) 12.7 (8.9) 4.3 (2.0) 10.4 (1.5) 15.9 (7.8) 12.0 (3.7) 

Theft (stolen) 0.0 (0.0) 0.3 (0.2) 0.2 (0.1) 1.8 (1.2) 0.9 (0.5) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious 

weeds, etc.) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 5.0 (2.5) 2.2 (1.1) 

Lambing problems N/A N/A N/A N/A N/A 

Other diseases 

(mastitis, footrot, 

boils, etc.) 4.7 (4.3) 0.6 (0.5) 6.8 (1.7) 2.7 (1.3) 3.7 (0.9) 

Other* 33.9 (15.0) 17.8 (7.6) 2.9 (0.9) 1.9 (0.5) 7.9 (2.2) 

Unknown 5.1 (4.1) 32.2 (7.7) 15.4 (1.9) 20.3 (5.8) 19.5 (3.2) 

Total 100.0 100.0 100.0 100.0 100.0 

*Being on back, lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

38 / Sheep Death Loss, 2004

In the West Central region, the percentage of losses due to theft ranged from

17.1 percent on operations with 1 to 24 sheep and lambs to 0.9 percent on

operations with 1,000 or more sheep and lambs.

b. For the West Central region, percentage of lamb death loss by cause and by

size of operation:

Percent Nonpredator Loss 

Size of Operation (Number of Sheep and Lambs)

 1–24 25–99 100–999 

1,000 

or More 

All 

Operations 

Nonpredator 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive 

problems (bloat, 

scours, 

parasites, 

enterotoxemia, 

acidosis, etc.) 15.1 (6.0) 31.9 (7.4) 24.9 (2.5) 29.7 (1.5) 27.9 (1.4) 

Respiratory 

problems 

(pneumonia, 

shipping fever, 

etc.) 12.2 (8.3) 4.2 (0.9) 18.7 (3.1) 24.5 (0.8) 20.5 (1.1) 

Metabolic 

problems (milk 

fever, twin lamb 

disease, 

pregnancy 

toxemia, etc.) 3.6 (2.7) 2.0 (1.1) 3.4 (1.0) 1.2 (0.2) 2.0 (0.3) 

Weather-related 

causes (chilling, 

drowning, 

lightning, etc.) 9.8 (5.9) 21.1 (7.5) 17.3 (2.7) 10.2 (0.6) 13.1 (1.1) 

Theft (stolen) 17.1 (14.6) 2.9 (1.6) 2.2 (1.6) 0.9 (0.4) 2.2 (1.0) 

Poisoning 

(nitrate 

poisoning, 

noxious feeds, 

noxious weeds, 

etc.) 0.6 (0.3) 3.2 (1.6) 3.6 (0.8) 6.6 (0.7) 5.2 (0.5) 

Lambing 

problems N/A N/A N/A N/A N/A 

Other diseases 

(mastitis, 

footrot, boils, 

etc.) 7.3 (5.7) 3.8 (1.8) 5.1 (0.9) 2.3 (0.3) 3.4 (0.4) 

Other* 13.0 (8.3) 9.1 (3.2) 4.9 (0.7) 4.1 (0.4) 5.2 (0.6) 

Unknown 21.3 (10.0) 21.8 (4.3) 19.9 (2.1) 20.5 (1.4) 20.5 (1.2) 

Total 100.0 100.0 100.0 100.0 100.0 

*Being on back, lameness, etc.
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 39

In the Central region, operations with 1 to 24 sheep and lambs had a higher

percentage of losses due to weather-related causes than operations with 1,000

or more sheep and lambs (18.8 percent and 9.9 percent, respectively).

c. For the Central region, percentage of lamb death loss by cause and by size

of operation:

Percent Nonpredator Loss 

Size of Operation (Number of Sheep and Lambs)

1–24 25–99 100–999 

1,000 or 

More 

All 

Operations 

Nonpredator 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive 

problems (bloat, 

scours, 

parasites, 

enterotoxemia, 

acidosis, etc.) 11.7 (2.8) 13.8 (1.8) 19.2 (1.2) 20.7 (1.8) 16.0 (1.0) 

Respiratory 

problems 

(pneumonia, 

shipping fever, 

etc.) 20.7 (4.3) 23.8 (4.1) 27.1 (1.3) 32.9 (1.7) 25.1 (1.7) 

Metabolic 

problems (milk 

fever, twin lamb 

disease, 

pregnancy 

toxemia, etc.) 1.0 (0.4) 3.4 (0.9) 1.5 (0.2) 1.8 (0.4) 2.1 (0.3) 

Weather-related 

causes (chilling, 

drowning, 

lightning, etc.) 18.8 (3.2) 12.6 (1.6) 11.3 (0.9) 9.3 (1.6) 13.1 (0.9) 

Theft (stolen) 0.1 (0.1) 0.4 (0.3) 0.1 (0.0) 0.1 (0.1) 0.2 (0.1) 

Poisoning 

(nitrate 

poisoning, 

noxious feeds, 

noxious weeds, 

etc.) 0.1 (0.1) 1.3 (0.8) 0.8 (0.2) 0.6 (0.2) 0.8 (0.3) 

Lambing 

problems 17.9 (3.3) 22.5 (2.2) 22.6 (1.8) 14.3 (2.2) 20.9 (1.2) 

Other diseases 

(mastitis, footrot, 

boils, etc.) 1.7 (1.0) 4.1 (1.0) 2.2 (0.4) 6.6 (1.3) 3.2 (0.4) 

Other* 7.3 (2.5) 6.9 (1.6) 5.5 (0.5) 1.7 (0.3) 6.0 (0.8) 

Unknown 20.7 (7.7) 11.2 (1.7) 9.7 (0.7) 12.0 (1.4) 12.6 (1.8) 

Total 100.0 100.0 100.0 100.0 100.0 

*Being on back, lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

40 / Sheep Death Loss, 2004

In the Northeast region, a lower percentage of lamb losses on operations with

1,000 or more sheep and lambs was due to unknown causes (3.0 percent)

compared to operations with 100 to 999, 25 to 99, and 1 to 24 sheep and lambs

(20.3 percent, 12.5 percent, and 19.3 percent, respectively).

d. For the Northeast region, percentage of lamb death loss by cause and by

size of operation:

Percent Nonpredator Loss 

Size of Operation (Number of Sheep and Lambs)

 1–24 25–99 100–999 

1,000 or 

More 

All 

Operations 

Nonpredator 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive 

problems (bloat, 

scours, parasites, 

enterotoxemia, 

acidosis, etc.) 10.3 (2.9) 13.7 (3.3) 17.3 (2.3) 31.0 (5.5) 14.4 (1.9) 

Respiratory 

problems 

(pneumonia, 

shipping fever, 

etc.) 10.7 (2.7) 14.7 (3.5) 19.3 (3.2) 25.3 (6.2) 15.4 (2.1) 

Metabolic 

problems (milk 

fever, twin lamb 

disease, 

pregnancy 

toxemia, etc.) 3.7 (1.4) 4.0 (1.6) 3.6 (1.7) 0.0 (0.0) 3.7 (1.0) 

Weather-related 

causes (chilling, 

drowning, 

lightning, etc.) 20.5 (4.3) 24.2 (4.8) 20.0 (3.8) 24.2 (5.5) 22.2 (2.8) 

Theft (stolen) 0.0 (0.0) 0.5 (0.5) 1.1 (0.6) 0.0 (0.0) 0.6 (0.3) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious 

weeds, etc.) 2.4 (1.5) 0.5 (0.2) 1.2 (0.6) 0.0 (0.0) 1.1 (0.4) 

Lambing problems 20.4 (3.7) 24.2 (4.5) 10.3 (1.7) 12.2 (3.3) 19.3 (2.6) 

Other diseases 

(mastitis, footrot, 

boils, etc.) 4.1 (2.5) 0.3 (0.2) 1.1 (0.4) 1.4 (0.5) 1.3 (0.6) 

Other * 8.6 (2.9) 5.4 (1.8) 5.8 (1.3) 2.9 (0.9) 6.1 (1.1) 

Unknown 19.3 (4.1) 12.5 (2.7) 20.3 (3.5) 3.0 (1.2) 15.9 (2.0) 

Total 100.0 100.0 100.0 100.0 100.0 

*Being on back, lameness, etc. 
Section II: Population Estimates, Nonpredator Losses

USDA APHIS VS / 41

For operations in the Southeast/Other region with 100 to 999 sheep and lambs,

70.4 percent of lamb losses were due to digestive causes. No other size group

lost such a large percentage of their lambs due to any one cause.

e. For the Southeast/Other region, percentage of lamb death loss by cause

and by size of operation:

Percent Nonpredator Loss 

Size of Operation (Number of Sheep and Lambs)

 

1–24 25–99 100–999 

1,000 or 

More* 

All 

Operations 

Nonpredator 

Cause Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error Pct. 

Std. 

Error 

Digestive 

problems (bloat, 

scours, parasites, 

enterotoxemia, 

acidosis, etc.) 22.3 (8.4) 14.6 (3.8) 70.4 (17.7) 38.2 (14.6) 

Respiratory 

problems 

(pneumonia, 

shipping fever, 

etc.) 15.1 (8.7) 9.1 (3.7) 6.0 (3.7) 9.5 (3.7) 

Metabolic 

problems (milk 

fever, twin lamb 

disease, 

pregnancy 

toxemia, etc.) 10.2 (6.8) 0.5 (0.2) 0.3 (0.2) 3.5 (2.6) 

Weather-related 

causes (chilling, 

drowning, 

lightning, etc.) 16.4 (6.9) 30.2 (10.0) 5.5 (3.3) 15.2 (5.0) 

Theft (stolen) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 

Poisoning (nitrate 

poisoning, noxious 

feeds, noxious 

weeds, etc.) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 

Lambing problems 8.8 (3.8) 29.2 (12.1) 5.7 (3.5) 12.6 (4.9) 

Other diseases 

(mastitis, footrot, 

boils, etc.) 1.7 (1.7) 0.4 (0.2) 3.1 (1.9) 1.8 (0.7) 

Other ** 12.8 (7.2) 6.1 (2.3) 3.1 (2.1) 6.9 (2.9) 

Unknown 12.7 (5.7) 9.9 (2.7) 5.9 (3.8) 12.4 (3.5) 

Total 100.0 100.0 100.0 100.0 

*Too few operations to report. 

**Being on back, lameness, etc.
Section III: Methodology

42 / Sheep Death Loss, 2004

Section III: Methodology

A. 1994 Death

Loss Study

1. Survey procedures

A random sample of U.S. producers was surveyed by NASS to provide data for

these estimates. Survey procedures ensured that all producers (except those in

Alaska) had an opportunity to be included in the survey, regardless of operation

size. Data were collected from approximately 75,000 cattle and sheep

producers during the first half of January by mail, telephone, and face-to-face

interviews. Large operations were sampled more heavily than small operations.

An additional nonprobability survey was also conducted in a few Western States.

Regardless of when producers responded, they were asked to report death

losses for sheep and lambs for the 1994 calendar year. Based on the original

data collected during January, a report entitled “Sheep and Goat Predator Loss”

was issued April 27, 1995. This report contained data for death loss by cause for

predators only and was on a State and regional level. Value of the losses was

also included. A subsequent NASS staff report, “Sheep and Lamb Death Loss,”

was published in May 1995. This report included both predator and nonpredator

dealth losses.

2. Estimation procedures

Total sheep and lamb death losses from all causes were published in the “Meat

Animals Production, Disposition, and Income, 1994 Summary” report by NASS

(released April 13, 1995). In setting the estimates for the report, total predator

and nonpredator losses were estimated as a percentage of total losses set

previously, and specific predator and nonpredator losses were estimated as a

percentage of total predator and nonpredator losses, respectively.

3. Reliability

Since all sheep producers were not included in the sample, survey estimates

are subject to sampling variability. Survey results are also subject to

nonsampling errors, such as omissions, duplications, and mistakes in reporting,

recording, and data processing. The effects of these nonsampling errors cannot

be measured directly. They are minimized through rigid quality controls in the

data collection process and through a careful review of all reported data for

consistency and reasonableness.
Section III: Methodology

USDA APHIS VS / 43

B. 1999 Death

Loss Study

1. Survey procedures

A random sample of U.S. producers was surveyed by NASS to provide data for

these estimates. Survey procedures ensured that all sheep producers,

regardless of operation size, had an opportunity to be included in the survey.

Large operations were sampled more heavily than small operations. About

13,800 producers were contacted during the first half of January by mail,

telephone, and face-to-face interviews.

2. Estimation procedures

Total death losses from all causes for sheep and lambs were as reported in

NASS’ “Meat Animals Production, Disposition, and Income, 2000 Summary”

report (released April 27, 2000).

In setting the predator loss estimates, total predator losses were estimated as a

percentage of total losses, and specific predator losses were estimated as a

percentage of total predator losses. NASS’ “Sheep and Goats Predator Loss”

report was published May 5, 2000. Nonpredator loss percentages by cause of

loss were generated by APHIS based upon analysis of the data collected in

January 1999, and published in December 2005.

3. Revision policy

Revisions to previous estimates of total death losses are made to improve the

current estimate. Previous-year estimates are subject to revision when current

estimates are made. Estimates for losses from all causes are subject to

revision in the following year’s “Meat Animals Production, Disposition, and

Income” report.
Section III: Methodology

44 / Sheep Death Loss, 2004

C. 2004 Death

Loss Study

1. Survey procedures

A random sample of U.S. producers was surveyed by NASS to provide data for

these estimates. Survey procedures ensured that all sheep producers,

regardless of operation size, had an opportunity to be included in the survey.

Large operations were sampled more heavily than small operations. About

22,000 operators were contacted during the first half of January 2005 by mail,

telephone, and face-to-face interviews.

2. Estimation procedures

Total death losses from all causes for sheep and lambs were as reported in

NASS’ “Meat Animals Production, Disposition, and Income—2004 Summary”

report (released April 2005). In setting the predator and nonpredator loss

estimates, total predator and nonpredator losses were estimated as a

percentage of total losses, then specific predator and nonpredator losses were

estimated as a percentage of total predator and nonpredator losses. Death

losses by predator and nonpredator cause of loss were published in NASS’

“Sheep and Goats Death Loss” report (released May 6, 2005).

Nonpredator cause of loss percentages by cause of loss by region and

operation were generated by APHIS based upon analysis of the data collected

in January 2005.

3. Revision policy

Revisions to previous estimates of total death losses are made to improve the

current estimate. Previous-year estimates are subject to revision when current

estimates are made. Estimates for losses from all causes are subject to

revision in the following year’s “Meat Animals Production, Disposition, and

Income” report.
Appendix

USDA APHIS VS / 45

Appendix: Discussion of Pre- and Postdocking Losses

In the Western States (Arizona, California, Colorado, Idaho, Oregon, Montana,

New Mexico, Nevada, Texas, Utah, Washington, Wyoming) NASS defines lamb

crop as lambs marked, docked, or branded. These States make up the Pacific

and West Central regions in this report. In the remaining States, lamb crop is

defined as lambs born. The individual State versions of the January 1 Sheep and

Goats Survey questionnaire reflect these differences.

For the States in the Pacific and West Central regions listed above, NASS

reports* only lamb losses that occurred after marking, docking, or branding.

However, the questionnaire used in the Pacific and West Central States did

include a question regarding lambs lost before marking, docking, or branding.

Five States (Colorado, Utah, Wyoming, Idaho, and Montana) publish State-level

losses separated into pre- and postdocking. These States also conduct cause-ofloss surveys on annual or biannual basis and publish the results.

The exclusion of predocking losses from the two reports is due to the fact that

lambs in the Pacific and West Central regions are usually born on range and,

therefore, less likely to be observed. It is difficult for producers in these regions

to accurately estimate the number of lambs both born and lost before marking,

docking, or branding. However, this method leads to the exclusion of a large

number of losses. In addition, no lambs lost due to lambing problems are

counted in these States, as these losses would obviously all occur in the

predocking period. Examination of the published predocking losses in the five

States provide an estimate of the magnitude of losses that occur before docking

(see table a).

With the exception of Colorado, over half of all reported lamb losses in the each

of the five States occurred in the predocking period. In Colorado, only about onethird of all losses (32.1% ) occurred predocking. The percentage of total predator

losses that occurred in the predocking period (table b) ranged from 20.0 percent

in Idaho to 48.1 percent in Wyoming. For nonpredator losses (table c), Idaho,

Montana, Utah, and Wyoming show at least two-thirds of reported nonpredator

losses occurred in the predocking period, while in Colorado, 26.1 percent of

nonpredator losses occurred in the predocking period.

* NASS publications: “Meat Animals, Production, Disposition, and Income” (April) and the periodic

published in May approximately every 5 years “Sheep and Goats Death Loss”
Appendix

46 / Sheep Death Loss, 2004

a. Number of postdocking lamb losses, predocking lamb losses, and predocking

lamb losses as a percentage of total lamb losses, by State:

Number of Lamb Losses 

State 

Postdocking 

NASS 

Reported 

Predocking 

State 

Reported Total 

Predocking 

Losses as a 

Percentage 

of Total 

Losses 

Colorado 19,000 9,000 28,000 32.1 

Idaho 12,000 13,000 25,000 52.0 

Montana 14,000 17,000 31,000 54.8 

Utah 18,000 19,800 37,800 52.4 

Wyoming 18,000 26,000 44,000 59.1 

b. Number of postdocking predator lamb losses, predocking predator lamb

losses, and predocking predator lamb losses as a percentage of total predator

lamb losses, by State:

Number of Predator Lamb Losses 

State 

Postdocking 

NASS 

Reported 

Predocking 

State Reported Total 

Predocking 

Losses as a 

Percentage of 

Total Losses 

Colorado 8,000 5,100 13,100 38.9 

Idaho 6,800 1,700 8,500 20.0 

Montana 7,900 2,900 10,800 26.9 

Utah 14,800 9,800 24,600 39.8 

Wyoming 14,000 13,000 27,000 48.1 
Appendix

USDA APHIS VS / 47

c. Number of postdocking nonpredator lamb losses, predocking nonpredator

lamb losses, and predocking nonpredator lamb losses as a percentage of total

nonpredator lamb losses, by State:

Number of Nonpredator Lamb Losses 

State 

Postdocking 

NASS 

Reported 

Predocking 

State 

Reported Total 

Predocking 

Losses as a 

Percentage 

of Total 

Losses

Colorado 11,000 3,900 14,900 26.2 

Idaho 5,200 11,300 16,500 68.5 

Montana 6,100 14,100 20,200 69.8 

Utah 3,200 10,000 13,200 75.8 

Wyoming 4,000 13,000 17,000 76.4