Grazing management of crested wheatgrass range for yearling steers Agropyron desertorum.

Sixty, spring-born, yearling steers of Angus-Hereford breeding were used to compare continuous vs short duration grazing on crested wheatgrass range. Grazing trials were conducted in two successive years. Grazing fields to remove about 30% of available forage and then moving to a fresh field increased (P<.O5) daily gains of steers compared to continuous grazing. However, this increase occurred late in the grazing season with no apparent initial advantage for short duration grazing. The effect of grazing treatments on forage yields and quality resulted in several management implications. These implications and further research needs are discussed. A successful grazing management plan should consider seasonal quality of forage resources, adapt them to animal requirements and maximize animal production without adversely affecting long- term forage production. Van Poollen and Lacey (1979) reviewed specialized grazing systems on western ranges and concluded that they increased mean annual forage production by 13% compared to continuous or season-long grazing. Reducing stocking levels had an even greater effect. Additionally, Allison and Kothmann (1979) found that with lower stocking levels animals selected higher quality diets. Crested wheatgrass on ranges of eastern Oregon has a growing season of April, May, and June. Forage is of high nutritive value early in the season but decreases rapidly in digestible protein and energy with increasing maturity. Young rapidly growing animals can efficiently utilize early season high quality forage and yearling steers can maintain daily gains above 0.8 kg through mid-June (Raleigh 1970). After this time, gains decrease with decreasing forage quality. Crested wheatgrass develops stiff unpalatable culms and a high stem to leaf ratio with increasing maturity. However, Hyder and Sneva (1963) have shown that adjusting stocking levels to achieve close grazing in late May, while plants are in the boot stage, will reduce formation of reproductive shoots and stimulate vegetative growth. The objectives of the current trials were to evaluate short dura- tion and continuous