Browsing Journal of Range Management, Volume 47, Number 2 (March 1994) by Subjects
Now showing items 1-4 of 4
Cattle preference for 4 wheatgrass taxaWe compared the preference of cattle for 12 entries, 2 of crested wheatgrass [Agropyron desertorum (Fischer ex Link) Schultes], 5 of thickspike wheatgrass [Elymus lanceolatus (Scribner & J.G. Smith) Gould ssp. lanceolatus], 3 of Snake River wheatgrass (proposed name E. lanceolatus spp. wawawaiensis), and 2 of bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) A. Love] in May 1989 and 1990 at Logan, Utah. Spaced plants were randomly arranged in 4 paddocks which were grazed once by 2 animals in late spring each year. Number of bites and number of visits were recorded for each entry in each paddock for the 2 animals individually. Cattle preferred Hycrest and Nordan crested wheatgrasses both years. Number of bites per plant for crested, thickspike, Snake River, and bluebunch wheatgrasses averaged 9.1, 4.3, 3.1, and 4.1, respectively, in 1989 and 6.7, 3.3, 3.5, and 3.6, respectively, in 1990. Number of visits was highly correlated with number of bites across entries. Grazing preference among entries was more highly correlated with biomass score and canopy height than basal area or maturity. Cattle preferred crested wheatgrass over the native wheatgrasses tested here during the spring grazing season.
Germination rate and emergence success in bluebunch wheatgrassDevelopment of plant materials adapted to the demands of a harsh environment and conditions created by standard planting practices has resulted in improved seedling establishment for some species. Bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] Love) is an important native bunchgrass often planted in the Intermountain and Pacific Northwest regions. Though cultivars have been developed, this species continues to have a reputation for weak seedlings. Forty-seven accessions of bluebunch wheatgrass collected from naturally occurring populations in 9 geographic regions and the cultivar 'Goldar' were evaluated for germination rate, seedling emergence and growth, and seed weight. Significant differences in seed weight and germination rate at optimum (15/25 degrees C) and cold (1 degree C) temperatures were observed. Seedling emergence from a 4-cm depth ranged from 5 to 66%. Mean dry shoot weight 28 days after planting varied among accessions by a factor of 6. Simple correlations between seed weight and percentage emergence (r = 0.62) and seed weight and mean shoot weight (r = 0.63) indicate seed weight could be used as a preliminary screening test for these traits. Seed weight was not useful in predicting germination rate. Results suggest establishment success may be improved through careful selection for traits associated with seedling vigor.
Optimization of range improvements on sagebrush and pinyon-juniper sitesThe optimum combination of 3 range improvements was determined for private lands on Utah ranches. While many promising range improvements are available, determination of which alternatives to implement must consider the total ranch operation. Linear programming (LP) makes it possible to simultaneously determine the profit maximizing combinations of range improvements and how these improvements will affect the total ranch operation. The study examined 3 range improvements (revegetation, burning, and chemical brush control) for big sagebrush (Artemisia tridentata Nutt.) and pinyon-juniper (Pinus spp.-juniperus spp.) on upland loam and upland shallow loam range sites. Net present value analysis and an LP model were used to identify the most efficient alternative, the limiting constraints, and the optimum levels and combinations of alternatives. The optimal solution ran 238 brood cows compared to 196 for the typical Utah ranch. Burning big sagebrush or pinyon-juniper infestations on crested wheatgrass (Agropyron desertorum Fisch. ex Link) foothill ranges was the most profitable range improvement. Annual net cash incomes after burning sagebrush or pinyon-juniper on the upland loam site were 37,873 and 37,770, respectively, compared to 31,278 on the typical Utah cow-calf operation. The optimal solution will change as input and product prices change. The model was designed for application to specific ranches rather than to make general recommendations for the typical Utah ranch.
Social facilitation influences cattle to graze locoweedMany ranchers claim that if a cow starts eating locoweed, she will teach others to eat it. Three grazing trials were conducted to evaluate the role of social facilitation in starting cattle to graze locoweed. The first trial was conducted near Gladstone, N.M., using mature cows grazing woolly locoweed (Astragalus mollissimus var. mollissimus Torr). The second trial was conducted on the Raft River Mountains in northwestern Utah, using yearling cattle grazing white locoweed (Oxytropis sericea Nutt). The third trial was conducted to determine if aversion-conditioned yearling cattle would consume white locoweed when placed with cattle that were eating locoweed (loco-eaters). Cattle conditioned to eat locoweed and naive animals in trials 1 and 2 first grazed in separate pastures to evaluate their initial acceptance of locoweed. The groups in the respective trials then were placed together to evaluate the influence of social facilitation on locoweed consumption. Locoweed consumption was quantified by bite count. Naive cattle in trials 1 and 2 sampled small quantities of locoweed while grazing separately. However, they greatly increased locoweed consumption when placed with the loco-eaters. Aversion-conditioned cattle in trial 3 did not consume locoweed while grazing separately. When placed with loco-eaters, they gradually increased consumption of white locoweed, in contrast to the immediate acceptance of locoweed by naive cattle in trials 1 and 2. The aversion extinguished and averted animals eventually accepted white locoweed at levels comparable to loco-eaters. Results of this study demonstrate that social facilitation can cause cattle to start eating locoweed.