The greatest proportion of dry-matter yields of annual and perennial ryegrass, as measured in rod-row field trials, occurred mostly in April, May and June at Davis, while orchardgrass yields were more evenly distributed throughout the harvest season. Ryegrasses generally were more vigorous and higher yielding than orchardgrass in the first year. Total seasonal yields in the first two years of the trial averaged 3.8 tons per acre for 14 perennial ryegrass selections and 3.4 tons per acre for five orchardgrass selections. These findings resulted under conditions of this trial and are not necessarily predictive of results under grazing management.