The number of beef cows in the United States increased from 32.7 million in 1964 to a record 45.7 million in 1975 and then steadily declined to 31.7 million in 1987. The average herd size increased from 24.7 million in 1964 to 37.6 million in 1987. The fragmented nature of acreage used for grazing will continue to limit herd size expansion. With limited herd size expansion, it will be difficult to achieve economies of size that producers with sufficient acreage obtain. Producers expand and reduce the national herd based on net cash beef cow income. Returns have generally not been consistently adequate to cover fixed asset replacement costs and to provide competitive labor, management, and investment returns. Many producers continue their activities, accept low returns, and probably subsidize their beef cow herds from other income sources.