• Bluegrass billbug feeding response to perennial triticeae grasses

      Nielson, D. C.; Asay, K. H.; Jones, T. A. (Society for Range Management, 1993-05-01)
      In a 4-year field study, 25 perennial triticeae grasses, representing a wide range of genomes and genome combinations, were evaluated as potential hosts for the bluegrass billbug (Sphenophorus parvulus Gyllenhal [Coleoptera: Curculionidae]). Root-sample data suggested that Russian wildrye (Psathyrostachys juncea [Fischer] Nevski) was unsuitable for billbug reproduction. Numbers of immatures varied significantly among remaining entries. Rhizomatous entries were more tolerant of billbug injury than caespitose entries. Plant mortality rates were frequently 50% or higher for self-pollinated caespitose entries with the SH genome complement (Elymus spp.). Losses to billbugs among the remaining species, particularly those with the J, N, and P genomes, were insignificant. Billbugs did not discriminate between native and introduced grasses, as resistant and susceptible entries were identified in both groups. The results obtained here may aid in selecting triticeae grasses for reseeding in areas where billbugs have damaged stands in the past.
    • Comparison of seeded and native pastures grazed from mid-May through September

      Hofmann, L.; Ries, R. E.; Karn, J. F.; Frank, A. B. (Society for Range Management, 1993-05-01)
      Cool-season introduced grass species are not recommended for season-long grazing in the northern Great Plains. They mature earlier than native species, which leads to an earlier loss in forage quality and palatability. A study conducted at Mandan, N.D., compared liveweight gains of yearling steers grazing crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.], smooth bromegrass (Bromus inermis Leyss.), and western wheatgrass [(Pascopyrum smithii (Rydb.) Love] and level native prairie (Class II and III land) and hilly native prairie pastures (Class IV and VI land), season-long. A set stocking rate of 1.5 AUM ha-1 was used from mid-May through late September in 1988, 1989, and 1990. Caged standing crop was higher from the seeded pastures than from the native pastures but liveweight steer gain was highest from the level native. Three-year average gains were 124, 114, 108, 106, and 105 kg per steer for level native, smooth bromegrass, western wheatgrass, hilly native, and crested wheatgrass pastures, respectively. The seeded cool-season grass pastures, grazed season-long at a rate 25% higher than that recommended by the SCS for native range, produced acceptable liveweight steer gains without additional inputs. Season-long grazing may provide an alternative use for marginal cropland and other highly erodible land that has been reseeded to cool-season species.
    • Decomposition of blue grama and rough fescue roots in prairie soils

      Dormaar, J. F.; Willms, W. D. (Society for Range Management, 1993-05-01)
      The mass of grass roots of blue grama (Bouteloua gracilis (HBK.) Lag. ex Steud) and rough fescue (Festuca campestris Rydb.) to a depth of 13 cm is similar but the carbon contents of their respective soils are quite different. The objective of the present study was to determine some of the physical and chemical changes of blue grama and rough fescue root masses during decomposition under both Brown (Mixed Prairie) and Black Chernozemic (Fescue Prairie) soil-forming conditions. Roots of each species in fine-mesh nylon bags were buried in the Ah horizon of both a Brown and a Black Chernozemic soil. Sixteen collections were made between November 1987 and June 1989 to determine diminution, loss of dry matter and gross energy, and changes in the concentration of carbon, nitrogen, methoxyl groups, alkaline-soluble organic acids and phenols, structural and nonstructural carbohydrates, lignin, and monosaccharides. Differences in substrate quality were only partially responsible for the increased decomposition of root mass in the Brown Chernozemic soil-forming environment. Comminution of root mass was significantly greater under the Mixed Prairie than under the Fescue Prairie conditions for both species. The nitrogen content of blue grama roots increased (from 1.17 to 1.56%) while that of rough fescue decreased (from 1.53 to 1.26%) significantly over the duration of the experiments at both sites. Methoxyl group content and energy levels were not useful parameters. Organic acid, phenols, and nonstructural carbohydrate contents decreased with time. Lignin concentration displayed a significant upward trend for both species (from 232 to 280 for blue grama and for 205 to 247 mg/g for rough fescue) in the Black Chernozemic soil only.
    • Diets of goats grazing oak shrubland of varying cover in northern Greece

      Papachristou, T. G.; Nastis, A. S. (Society for Range Management, 1993-05-01)
      The effects of 3 brush cover proportions (Low Brush pasture: 52% brush/32% herbage, Medium Brush pasture: 62% brush/20% herbage, and High Brush pasture: 66% brush/12% herbage) on dietary selection of goats in northern Greece were investigated. Diet samples were collected from esophageally fistulated goats during 14 grazing periods at monthly intervals from June 1987 to July 1988. Kermes oak foliage (Quercus coccifera L.) was the main component of the available forage in all pastures during all grazing periods. The herbaceous component contributed more than 50% for the goats' diet during spring for Low Brush pasture, 46% for Medium Brush pasture, and 40% for High Brush pasture. In the remaining grazing periods, goats selected larger quantities of browse. For Low Brush pasture browse contribution ranged from 48% to 66%, for Medium Brush from 54% to 77%, and for High Brush from 66% to 80%. Leaves of all forage species contributed more than 56% during all test periods. The quantities of twigs from shrubs and stems from herbaceous species were low but constant during all test periods. Fruits and flowers, despite representing low percentages of the overall production, were important for the animals' nutrition, since they provided a high percentage of nutrients. Our results indicated that goats adapted diets to forage class availability.
    • Droplet size and spray volume effects on honey mesquite mortality with clopyralid

      Whisenant, S. G.; Bouse, L. F.; Crane, R. A.; Bovey, R. W. (Society for Range Management, 1993-05-01)
      The effects of droplet size and spray volume (spray-mixture application rate) on honey mesquite (Prosopis glandulosa Torr.) mortality were evaluated using 0.55 to 0.58 kg ae (acid equivalent) ha-1 clopyralid (3,6 dichloro-2-pyridinecarboxylic acid). A factorial combination of 3 spray volumes (19, 37, and 75 liters ha-1) and droplet sizes of 325 +/- 25, 475 +/- 25, and 625 +/- 25 micrometers nominal volume median diameter were replicated 3 times at both Andrews and Big Lake, Tex., during June 1989. The experiment was repeated in 1990 at Big Lake and Campbellton, Tex., without the 75 liters ha-1 spray volume. Honey mesquite mortality and canopy reduction 16 months after application were significantly less on the 625 micrometer droplet treatments in 2 of 4 experiments, when compared to plots treated with smaller droplet sizes. Mortality increased with larger spray volumes, particularly with 625 micrometer droplets. Relative mortality data from the 4 experiments clearly demonstrated that larger droplet sizes require larger spray volumes for greatest efficacy.
    • Efficacy of fenbendazole against gastrointestinal nematodes in whitetailed deer

      Schultz, S. R.; Barry, R. X.; Forbes, W. A.; Johnson, M. K. (Society for Range Management, 1993-05-01)
      We provided fenbendazole to captive (N = 77) and free-ranging (3 study areas) white-tailed deer (Odocoileus virginianus) in Louisiana to determine effects on gastrointestinal nematode burdens. Fenbendazole reduced gastrointestinal nematode burdens of captive and free-ranging white-tailed deer. Mean eggs per gram of feces from captive deer decreased (P < 0.01 and P < 0 .01, respectively) 89% and 84% after provision of fenbendazole in doses approximating 0.47 and 0.62 g/deer, respectively. Doses approximating 0.42-0.46 g/deer did not affect (P = 0.61) eggs per gram of feces collected from free-ranging deer. Mean eggs per gram of feces collected from free-ranging deer was affected by fenbendazole treatment (P = 0.04) and decreased an average of 86% (SE = 1.9) on the 3 study areas after provision of fenbendazole in doses approximating 1.67-1.82 g/deer. Eggs per gram of feces collected from the distal colon and abomasal parasite counts from abomasa of free-ranging deer harvested on the study areas were associated positively (r = 0.706, P < 0 .001), were affected by fenbendazole treatment (P < 0.01 and P < 0 .01, respectively), and decreased 66% (SE = 5.1) and 52% (SE = 7.4), respectively, after provision of fenbendazole in doses approximating 1.67-1.82 g/deer. A reduction in the crosstransmission of gastrointestinal parasites common to deer and livestock might be possible through fenbendazole treatment of deer.
    • Forage response to N, P, and S fertilization on clearcut lodgepole pine sites

      Wikeem, B. M.; Newman, R. F.; Va, A. L. (Society for Range Management, 1993-05-01)
      The response of selected plant species to a single application of factorial combinations of nitrogen (N), phosphorus (P), and sulfur (S) on 2 lodgepole pine (Pinus contorta Dougl.) clearcut-logged sites in British Columbia was evaluated over 3 years. Increasing N rates typically resulted in higher forage standing crop on both sites, in all years. but standing crop at Fly Creek was nearly double that at Beaverdam Lake. On both sites, forage yields peaked at 400 kg N/ha in 1982 and carry-over of the fertilizer effect lasted for 3 years although yields declined annually. Addition of P to N applications enhanced (P < 0.05) total standing crop, other grass standing crop, and pinegrass (Calamagrostis rubescens Buckl.) standing crop at Beaverdam Lake and grass standing crop at Fly Creek, but had no effect (P > 0.05) on other species and groups. Sulfur, added to N applications, enhanced total yields compared to control on both clearcuts although at Fly Creek this response nearly doubled that produced at Beaverdam Lake. Nitrogen fertilization increased (P < 0.05) pinegrass crude protein (CP) content, particularly in the first year after fertilization. Acid detergent fiber (ADF) generally increased in response to increasing N levels in 1982, but declined compared to control in 1983 and 1984. Elevated forage CP levels, litter N concentrations, and soil N levels in 1984 indicated that the carry-over response on these forest sites resulted directly from N remaining in the soil or again becoming available for plant growth.
    • Germination response of hand-threshed Lehmann lovegrass seeds

      Hardegree, S. P.; Emmerich, W. E. (Society for Range Management, 1993-05-01)
      Germination of Lehmann lovegrass (Eragrostis lehmanniana Nees) was increased by seed after-ripening and by mechanical scarification of the seed coat. Hand-threshed seeds collected from 5 sites in southern Arizona were periodically germinated over the water potential range of 0 to -1.55 MPa for 98 weeks after harvest. Nonscarified seeds exhibited very low germination at all water potentials for the entire length of the study. Total percent germination of scarified seeds peaked after 34 weeks. Seeds scarified before the after-ripening requirement was met germinated without further scarification at 46 weeks after harvest. Measurements of water uptake rates indicate that seed cost permeability to water contributes little to the increased germinability of scarified seeds.
    • Influence of handling methods on fecal NIRS evaluations

      Pearce, R. A.; Lyons, R. K.; Stuth, J. W. (Society for Range Management, 1993-05-01)
      Experiments were conducted to investigate efficiency in analysis of fecal samples by near infrared reflectance spectroscopy (NIRS) to predict cattle forage diet quality. Stability of fecal samples during shipping and methods of reducing analysis time were evaluated. In experiments with actual and simulated shipping, no difference was found between predictions from samples shipped fresh or frozen, allowing analysis time to be reduced by 1 day. Drying procedures were developed which allowed sample analysis 24 hours after arrival in the lab for an additional reduction of 1 day in analysis time. Minimal effects on NIRS predictions were observed for simulated shipping delays up to 12 days for crude protein and 14 days for digestible organic matter.
    • Influence of rest-rotation cattle grazing on mule deer and elk habitat use in east-central Idaho

      Yeo, J. J.; Peek, J. M.; Wittinger, W. T.; Kvale, C. T. (Society for Range Management, 1993-05-01)
      Elk (Cervus elaphus Linnaeus), mule deer (Odocoileus hemionus Rafinesque), and cattle (Bos taurus Linnaeus) distributions were determined year round from 1975-1979 on a rest-rotation grazing system established in steep mountainous terrain. Following implementation of the grazing system, cattle progressively used higher elevations and steeper slopes in each succeeding year. Elk preferred rested pastures during the grazing season (June-October) and avoided habitat frequented by cattle by using higher elevations and steeper slopes. Few mule deer used the allotment during summer, but during the winter, deer selected habitats grazed previously by cattle. Elk appeared to adjust to the grazing system by making greater use of pastures with cattle present, although preference for pastures without cattle continued.
    • Influence of ruminally dispensed monensin and forage maturity on intake and digestion

      Fredrickson, E. L.; Galyean, M. L.; Branine, M. E.; Sowell, B.; Wallace, J. D. (Society for Range Management, 1993-05-01)
      Eight ruminally cannulated crossbred steers (average weight 336 kg) grazing native blue grama (Bouteloua gracilis [H.B.K.]) rangeland were used in a repeated measures design to evaluate effects of monensin ruminal delivery devices (MRDD) and forage phenology on ruminal digestion. Three periods were assessed: mid-August (Aug.), early October (Oct.), and mid-November (Nov.). One MRDD was placed in the reticulum of 4 steers via the ruminal cannula 21 days before each period. Intake was estimated using total fecal collections. Diet samples were collected using 3 esophageally fistulated steers. Ruminal fill was measured by ruminal evacuation; rate and extent of in situ ruminal neutral detergent fiber disappearance were estimated before ruminal evacuations. Ruminal passage rates, retention time, and apparent total tract organic matter digestibility were estimated using indigestible neutral detergent fiber. In vitro organic matter disappearance of esophageal masticate did not differ (P > .05) in Aug. and Oct. (average of 53.7%), but declined (P < .05) in Nov. (48.7%), whereas organic matter digestibility was greater (P < .10) in Aug. (62.3%) than in either Oct. (55.2%) or Nov. (53.9%). Release of monensin from the bolus (68 mg day-1) was less than expected (100 mg day-1). Intake, organic matter digestibility, ruminal passage rates, retention time, pH, and ammonia were not affected (P > .10) by MRDD. In situ neutral detergent fiber disappearance at 96 hours was decreased (P < .10) by MRDD (68 vs 65% for control and MRDD, respectively). As the grazing season progressed, intake declined (P < .10), whereas ruminal fill and retention time increased (P < .05), and passage rate of indigestible neutral detergent fiber decreased (P < .05). At 48 hours in situ neutral detergent fiber was greatest (P < .05) in Aug. and least (P < .05) in Nov.
    • Nutrient composition of whitetop

      McInnis, M. L.; Larson, L. L.; Miller, R. F. (Society for Range Management, 1993-05-01)
      Whitetop or heart-podded hoary cress (Cardaria draba (L.) Desv.) is an Eurasian native of the Cruciferae actively invading rangelands throughout western North America. The plant is reported to be unpalatable to livestock and contain potentially toxic glucosinolates. Practical experience indicates sheep consume whitetop during its early growth stages and cattle ingest large quantities of seedheads. Chemical analysis of whole plants from rosette to hard seed, respectively, indicated the following trends: crude protein (28.8 to 7.9%), neutral detergent fiber (13.1 to 52.8%), acid detergent fiber (12.0 to 41.8%), cellulose (9.9 to 32.1%), lignin (1.9 to 9.4%), ether extract (1.6 to 2.4%), in vitro organic matter digestibility (77.3 to 49.1%), digestible energy (2.9 to 1.8 Mcal/kg), and total glucosinolates (28.4 to 84.0 micromoles/g). Leaves were higher than stems in crude protein, ether extract, in vitro organic matter digestibility, and digestible energy. Analysis of 11 micro- and macroelements revealed sulfur (S) levels ranged from 0.73 to 2.69% and were therefore higher than the reported maximum tolerable level (0.4%). High S levels likely reflected the S moiety of glucosinolates and their hydrolysis products. Whitetop has some forage value, but until further research establishes the toxicity of this species to sheep and cattle, prudence suggests managers use caution when allowing animals to graze whitetop-infested rangelands by providing supplemental iodine, utilizing mature and nonlactating animals, and reducing opportunities for animals to consume the plant.
    • Plant structure and the acceptability of different grasses to sheep

      O'Reagain, P. J. (Society for Range Management, 1993-05-01)
      Plant structure should be an important determinant of species acceptability to grazing ungulates functioning under various time-energy constraints. The acceptability of 9 grasses to sheep grazing a secondary grassland community in spring, summer, and autumn in South Africa was related to the following species attributes: plant height, leaf table height, tussock diameter, stemminess, percent leaf, leaf density, percent dry matter (DM), leaf tensile strength, and leaf crude protein (CP). Species acceptability over the grazing season was positively related to tussock diameter (P less than or equal to 0.05) but negatively related (P less than or equal to 0.01) to leaf tensile strength and DM. Discriminant function analysis successfully discriminated between species in different acceptability classes in summer (P less than or equal to 0.05) and autumn (P less than or equal to 0.01) using a combination of plant structure and leaf quality attributes. Correspondence analysis indicated that preferred species were generally short and nonstemmy and had leaves of low DM, low tensile strength, and high crude protein content. Conversely, avoided species tended to be tall and stemmy with a high leaf table height, and had leaves of high DM and tensile strength but low CP levels. It is concluded that, for sheep, acceptability is determined by a combination of plant structure and leaf quality attributes.
    • Technical Notes: Botanical components of annual Mediterranean grassland as determined by point-intercept and clipping methods

      Glatzle, A.; Mechel, A.; Va, M. E. (Society for Range Management, 1993-05-01)
      Three methods for determining proportions of botanical components, i.e., grasses, legumes, and forbs (nonleguminous dicots), of continuously grazed Mediterranean pastures were compared. Percentage contribution to dry matter yield was determined by sample clipping and separating into botanical components. Both percentage of sward and specific contribution were determined by the point-intercept method. These were defined by the relative contribution of 1 botanical component to the total number of counted intercepts between 200 pins inserted vertically into the sward and all botanical components. For specific contribution only the number of pins contacted by the various botanical components were considered, whereas for percentage of sward even multiple contacts between a pin and plant parts of a particular botanical component were taken into account. Percentage contribution was highly significantly correlated with percentage of sward (R = 0.92) and specific contribution (R = 0.93) running the analyses across all botanical components, although there was a significant trend to underestimate forbs and overestimate legumes by the point-intercept methods. It is concluded, however, that for most practical purposes determination of specific contribution, the least laborious method, should give satisfactory estimates of percentage contribution.
    • Viewpoint: Selection for improved drought response in cool-season grasses

      Johnson, D. A.; Asay, K. H. (Society for Range Management, 1993-05-01)
      Water limits the establishment, growth, and production of cool-season grasses on semiarid rangelands, and plant improvement programs for these areas must be capable of screening breeding lines for response to drought. Although many techniques to evaluate various morphological and physiological characteristics have been proposed, few have been used successfully in plant breeding programs. Consequently, a need exists to identify and develop rapid, reliable screening techniques that can assess integrated plant response to drought in large plant populations. Improved seedling emergence has been achieved in Russian wildrye [Psathyrostachys juncea (Fischer) Nevski] by selecting for emergence from a deep seeding depth and long coleoptiles. Water uptake by roots is critical, and screening for enhanced seedling root growth in cool-season grasses offers considerable promise. In spite of the important role that stomatal control has in regulating plant water loss, limited success has been achieved in incorporating desirable stomatal characteristics into improved grass cultivars. Although osmotic adjustment appears beneficial in some crop species, more research is needed before cool-season grasses should be selected based on osmotic adjustment. Selection for improved water-use efficiency in cool-season grasses based on carbon isotope discrimination is a promising approach. Successful incorporation of these various traits into improved cool-season grass cultivars necessitates close cooperation between breeders and physiologists.
    • Water quality effects on stability and phytotoxicity of picloram and clopyralid

      Whisenant, S. G.; Bovey, R. W. (Society for Range Management, 1993-05-01)
      Water quality effects on stability of picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid) and clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) were evaluated by determining their concentrations in spray mixtures 0, 48, and 168 hours after mixing. Gas chromatography was used to evaluate picloram and clopyralid concentrations in spray solutions mixed with different water sources or buffered water solutions. At 168 hours picloram concentrations in water from La Copita and Midland, Texas, were 11 and 12% lower than at 0-hour and 5 and 6% lower than picloram concentrations in distilled water at 168 hours. Water quality effects on phytotoxicity to honey mesquite (Prosopis glandulosa) were evaluated at 0 and 168 hours after mixing the spray solution. Water quality had no effect on clopyralid phytotoxicity to honey mesquite at either 0 or 168 hours after mixing. Phytotoxicity to honey mesquite was reduced 42% when picloram mixtures were used 168 hours after mixing with water from La Copita. This indicates the potential for reduced phytotoxicity from picloram when prepared spray solutions are not used for 7 days.