PREFERENCES AND BEHAVIOR OF CATTLE GRAZING 8 VARIETIES OF GRASSES

We compared the forage preferences of steers grazing among 8 varieties of grasses at 2 stages of phenology on the Northern Great Basin Exper imental Range near Burns, Ore. Varieties included: 'Nordan' (Agropyron desertorum (Fischer ex Link)Schultes) and 'CD-II' (A. desertorum XA. cristatum (L.) Gaertner) crested wheatgrass; 'Magnar' and 'Trailhead' Basin wildryes (Leymus cinereus (Scribner & Merrill) A. Love); 'Goldar ' bluebunch wheatgrass (Pseudoroegneria spicata (Pursh)A. Love); 'Bozo isky-Select' Russian wildrye (Psathyrostachys junceus (Fischer) Nevski ); 'Bannock' thickspike wheatgrass (Elymus lanceolatus ssp. lanceolatu s (Scribner & J.G. Smith) Gould), and 'Secar' Snake River wheatgrass ( proposed nomenclature Elymus lanceolatus ssp. wawawaiensis (Scribner & J.G. Smith) Gould). Three esophageal-fistulated steers grazed each pa ddock, with 3 paddocks grazed at the boot stage of development, and 3 paddocks grazed after grasses entered quiescence. In boot-stage trials , steers were very selective and collectively harvested 53% of total b ites from the preferred CD-II and Nordan. These crested wheatgrasses a lso ranked higher (P < 0.05) in bites/visit and time/visit. Magnar, Tr ailhead, and Bozoisky-Select were avoided. When grasses were quiescent , steers were less selective; and CD-II, Nordan, Goldar, Bannock, and Bozoisky-Select were all equally acceptable. Magnar and Trailhead were again avoided. Steers consistently took more bites (P < 0.05) from pr eferred forages and regrazed preferred plants before any variety was d epleted. Mean distance traveled between successive feeding stations wa s greater during boot-stage trials (2.4 m) than at quiescence (1.4 m), suggesting steers searched among the nearest 48 neighboring plants in boot-stage trials and the nearest 24 neighbors during quiescence. Mea sures of grazing time per variety were strongly correlated (r > 0.95, P < 0.01) with total bites harvested from varieties and are probably a dequate for ranking relative preferences of steers. By selectively gra zing at both stages of phenology, cattle diets were higher in CP, P, a nd ADL than the standing crop. During boot-stage trials, diets were al so higher in Ca and Mg than forage analyses would suggest. Except for phosphorus, the nutritive content of all varieties was satisfactory fo r lactating beef cattle at both stages of phenology. Given their prove n ease of establishment, competitive ability, nutritional value, grazi ng tolerance, and high relative palatability, we suggest the crested w heatgrasses (CD-II and Nordan), are excellent candidates for reclaimin g or establishment of pastures for beef production programs in the nor thern Great Basin.