Preference and behavior of cattle grazing 8 varieties of grasses.

Abstract

We compared the forage preferences of steers grazing among 8 varieties of grasses at 2 stages of phenology on the Northern Great Basin Experimental Range near Burns, Ore. Varieties included: 'Nordan' (Agropyron desertorum (Fischer ex Link)Schultes) and 'CD-II' (A. desertorum X A. cristatum (L.) Gaertner) crested wheatgrass; 'Magnar' and 'Trailhead' Basin wildryes (Leymus cinereus (Scribner &Merrill) A. Love); 'Goldar' bluebunch wheatgrass (Pseudoroegneria spicata (Pursh)A. Love); 'Bozoisky-Select' Russian wildrye (Psathyrostachys junceus (Fischer) Nevski); 'Bannock' thickspike wheatgrass (Elymus lanceotatus ssp. lanceolatus (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 paddock, 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 bites from the preferred CD-II and Nordan. These crested wheatgrasses also ranked higher (P < 0.05) in bites visit and time/visit. Magnar, Trailhead, 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 preferred forages and regrazed preferred plants before any variety was depleted. Mean distance traveled between successive feeding stations was greater during bootstage 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. Measures of grazing time per variety were strongly correlated (r > 0.95, P < 0.01) with total bites harvested from varieties and are probably adequate for ranking relative preferences of steers. By selectively grazing at both stages of phenology, cattle diets were higher in CP, P, and ADL than the standing crop. During boot-stage trials, diets were also higher in Ca and Mg than forage analyses would suggest. Except for phosphorus, the nutritive content of all varieties was satisfactory for lactating beef cattle at both stages of phenology. Given their proven ease of establishment, competitive ability, nutritional value, grazing tolerance, and high relative palatability, we suggest the crested wheatgrasses (CD-II and Nordan), are excellent candidates for reclaiming or establishment of pastures for beef production programs in the northern Great Basin.