vertically integrated. Farms are owned and managed independently of processors. Most dairy farms raise their own replacement heifers but sell bull calves. Fluid milk is sold to processors, which may be controlled by cooperatives or by private or public corporations. (See Blayney, 2002, and Manchester and Blayney, 1997, for further exposition of structure and trends in the U.S. dairy sector.)

Beef Cattle. The number of beef cattle in the United States peaked at 132 million head in 1975. USDA estimated that in 2001 the U.S. cattle inventory was 96.7 million head and that there were 1.05 million cattle operations (operations with at least one or more head of beef or dairy cattle). Many of these are cow-calf operations, with cattle fed on pasture, that are not considered AFOs. For example, 0.65 million cattle operations had fewer than 50 head of cattle and accounted for 11.5 percent of the United States cattle inventory in 2001 (USDA, 2002e). Feedlots vary in size, from a great many operations that hold only a few animals to a small number with a one-time occupancy capacity of more than 100,000 head.

The cattle feeding industry has not developed integration or contractual arrangements to the extent that the poultry or swine industries have. Most feedlots are privately held; an owner may have more than one, but ownership of a feedlot does not necessarily mean ownership of the cattle being fed there. Custom feeding is common where an investor who owns the cattle may have no active involvement in cattle feeding or agriculture except through an investment portfolio.

Cattle farmer-feeder operations are those in which much of the feed used in the feedlot is derived from owned or rented cropland that is part of the operator’s overall agricultural operation. These operations may involve feedlots with capacities as large as 10,000-12,000 head. Most farmer-feeder operations probably have a one-time capacity of <2500 head. Large commercial feedlots may have a substantial land base for feed production but in most instances would have to purchase a significant portion of the feed needed.

Custom feeding (housing and feeding cattle on a feedlot for a fee; the cattle are not owned by the feedlot owner) is common. Cow-calf operators who do not have a feedlot may also utilize custom feeding after their cattle have been weaned. The proportion of custom-fed cattle within a feedlot is not necessarily related to overall size of the feedlot. It has become increasingly common for smaller farmer-feeder operations to use custom feeding as a way to decrease risk or to capitalize expansion.

Pigs. Almost all of the U.S. inventory of pigs in each of the three phases of production is housed in buildings. There were 81,130 farms with at least one pig on December 1, 2001. Of those, 84.6 percent had fewer than 1000 pigs in inventory and maintained 13.5 percent of the 58.8 million pigs in the country; 8.6 percent have at least 2000 pigs in inventory and maintained 74.5 percent of the U.S. inventory of pigs (USDA, 2001).

Front Matter (R1-R22)

Executive Summary (1-13)

1. Introduction (14-25)

2. Livestock Agriculture and Animal Feeding Operations (26-49)

3. Air Emissions (50-73)

4. Measuring Emissions (74-97)

5. Approaches for Estimating Emissions (98-128)

6. Government Regulations and Programs (129-151)

7. Improving Knowledge and Practices (152-168)

8. Conclusions (169-175)

References (176-194)

Appendix A: Statement of Task (195-197)

Appendix B: Acronyms and Glossary (198-204)

Appendix C: Bioaerosols (205-206)

Appendix D: Nitrogen and Sulfur Contents of Animal Products and Live Animals -- Sample Excretion Predictions (207-213)

Appendix E: Animal Units (214-216)

Appendix F: Ammonia Emissions from Manure Storage (217-221)

Appendix G: Regulatory Action Levels by Selected Atmospheric Pollutant (222-223)

Appendix H: Regulatory Action Levels by Regulatory Requirement and Action Status (224-225)

Appendix I: Emission Factors for a Feed Mill or Grain Elevator (226-227)

Appendix J: Public Meeting Agendas (228-233)

Appendix K: Geographic Distribution of Livestock and Poultry Production in the United States for 1997 (234-240)

Appendix L: Emisson Factors in Published Literature (241-254)

About the Authors (255-260)

Board on Agriculture and Natural Resources Publications (261-264)