bluuebunny/crossref_metadata_2025 huggingface dataset:
Intermediate wheatgrass and Russian wildrye responses to defoliation and moisture
Authors: Hendrickson J. R. , Berdahl J. D. ,   Society for Range Management
Published: March 2016

Perennial forage grasses in the Northern Great Plains are often grazed under water-limiting conditions. The effects of defoliation and soil moisture dynamics on herbage yield, tiller recruitment and number of crown positions for 2 perennial forage grasses were evaluated in a greenhouse experiment at Mandan, N.D. Intermediate wheatgrass (Thinopyrum intermedium (Host) Barkw. D.R. Dewey] and Russian wildrye (Psathyrostachys juncea (Fisch.) Nevski] were grown at 75, 50, or 40% of field capacity and left as undefoliated controls or defoliated at 10-day intervals to an 8- or 4-cm stubble height. Cumulative herbage yield exhibited defoliation level by soil moisture (P = 0.0001) and species by defoliation (P = 0.007) interactions. Yield decreased with increasing defoliation intensity at 75 and 50% of field capacity, but at 40% of field capacity only the most intense defoliation level was significantly affected. Russian wildrye produced more herbage (1.97 g plant(-1)) than intermediate wheatgrass (1.36 g plant(-1)) under severe defoliation level. Increased defoliation intensity (P = 0.0001) but not water availability (P > 0.05) decreased tiller numbers. Pooled across all treatments, Russian wildrye produced 10 tillers per plant and intermediate wheatgrass produced 7 (P = 0.0001). This may partially explain Russian wildrye's greater grazing tolerance. The number of crown positions (potential axillary bud sites in the bottom 20mm of the plant) was similar between species suggesting that increased tiller numbers in Russian wildrye occurred because its axillary buds were more readily activated than intermediate wheatgrass. Moderate and severe defoliation reduced the number of crown positions on parent seedlings to only 62 and 50% of the number of crown positions of control seedlings, respectively. Water stress decreased (P = 0.004) number of crown positions at 40% of field capacity but only when crown positions of both parent and daughter tillers were pooled. In this experiment, defoliation had a greater effect than water stress. Moisture level mainly affected tiller size not numbers. The interaction between defoliation and water stress should be examined in field studies to foster improved management of these 2 grasses.
Soil erosion as affected by shrub encroachment in northeastern Patagonia
Authors: Parizek B. , Rostagno C. M. , Sottini R. ,   Society for Range Management
Published: March 2016

Soil erosion is the primary cause of irreversible loss of soil productivity on most rangelands. In northeastern Patagonia, the increase in soil erosion has been closely associated with the increase in shrub cover in the grass or shrub-grass steppes. We used rainfall simulation to compare infiltration and sediment production from patches of grass, shrub-grass, and shrub steppes of the Punta Ninfas range site. Bare soil and gravel covers were higher and litter cover was lower in the shrub steppe than in the shrub-grass and the grass steppes. In the shrub inter-spaces of the shrub steppe, bulk density was greater and macroporosity and soil organic matter were lower (P less than or equal to 0.05) than in the mounds beneath shrubs and in the grass and shrub-grass areas. Infiltration rate was 60 to 65% lower in the shrub steppe than in the grass and shrub-grass steppes, respectively. On the contrary, total sediment production and concentration were higher (P less than or equal to 0.05) in the shrub steppe as compared to the grass and the shrub-grass areas. Gravel cover was the variable that best predicted infiltration and sediment production. The organic matter content of the sediment, mostly litter, in the shrub and the shrub-grass steppes were similar and greater (P less than or equal to 0.05) than in the grass steppe. Runoff litter removal may represent one of the processes that drive the transition from shrub-grass to shrub steppes. High rates of sediment removal, mainly litter, from the shrub interspaces of the shrub steppe may limit the natural recovery of the soil physical and hydrological properties. These degraded patches fail to capture incident rainfall and restrict the possibilities for the recovery of perennial grasses favoring the dominance of shrubs.
Cheatgrass competition and establishment of desert needlegrass seedlings
Authors: Rafferty D. L. , Young J. A. ,   Society for Range Management
Published: March 2016

Desert needlegrass (Achnatherum speciosum [Trin. Rupr.] Barkworth) is potentially a valuable native species for use in restoration seedings in the more arid portions of the Great Basin. Seedlings of desert needlegrass were grown in a greenhouse with 5 different densities of cheatgrass (Bromus tectorum L.). The densities of cheatgrass used in the greenhouse experiments were derived from sampling populations in the field where desert needlegrass is adapted and seedling recruitment is desired. Cheatgrass is known to close sites to the establishment of seedlings of perennial grasses through competition for moisture. The response variable was height of desert needlegrass shoots. Height measurements were taken weekly for 12 weeks following seedling emergence. During the first 5 weeks following emergence there were no significant (P less than or equal to 0.05) differences in the height of desert needlegrass seedlings among treatments. From week 5 through week 12, there was a highly significant (P less than or equal to 0.001) difference in the height of desert needlegrass shoots between the control and all levels of cheatgrass density. Reducing the density of cheatgrass seedlings in the greenhouse to the equivalent of 25% of the density present in the field still did not allow the establishment of the perennial grass seedlings. Even though desert needlegrass is adapted for natural establishment in the drier portions of the central Great Basin, some form of cheatgrass control is required for the perennial grass seedling establishment if cheatgrass is present. Cheatgrass control has to be more than a reduction in density, it has to be near complete control of the annual grass.
Salinity affects development, growth, and photosynthesis in cheatgrass
Authors: Rasmuson K. E. , Anderson J. E. ,   Society for Range Management
Published: March 2016

The effects of salt stress on growth and development of cheatgrass (Bromus tectorum L.) were investigated in 2 greenhouse studies. The first study assessed developmental and physiological responses of this grass to 4 salinity levels. Salinity stunted growth through reduced leaf initiation and expansion, and reduced photosynthetic rates. Reduction of photosynthetic rates appeared to be primarily due to stomatal limitation. Salinity also reduced carbon isotope discrimination, indicating long-term effects on conductance and carbon gain. Root growth was severely inhibited by high salinity, resulting in a shift in the root to shoot allocation pattern. The second study investigated growth patterns of cheatgrass in relation to intraspecific variation in salt tolerance using plants grown from seeds collected at non-saline and saline sites. Salinity reduced growth of plants from both environments. However, plants from the saline site accumulated leaf and root area at nearly twice the rate as those from the non-saline site, even in the control group. Because plants were grown in a common environment, growth differences between populations were genetically based. Thus, the potential for rapid growth may enable plants from the saline site to rely on shallow, less saline moisture reserves available early in the growing season.
Windrow grazing and baled-hay feeding strategies for wintering calves
Authors: Volesky J. D. , Adams D. C. , Clark R. T. ,   Society for Range Management
Published: March 2016

Management practices that lower livestock production costs are of interest to ranch enterprises. Windrow or swath grazing is a strategy where livestock directly graze windrow-stored forage, generally during a time when packaged hay or some other feed is provided. The objectives of this study were: 1) to quantify calf performance and forage intake and waste under windrow grazing (windrow) and bale-fed (bale) management strategies; 2) to quantify hay quality changes as affected by storage method and time; 3) to determine the effects of windrow coverage on subsequent meadow herbage yield and composition; and 4) to compare costs and returns associated with windrow and bale strategies. The forage source was wet meadow dominated by cool-season perennial species with alternating windrows baled and the remaining windrows left in place for direct grazing. Weaned steer calves were fed baled hay or grazed windrows during a November-January period each of 2 years. Windrow grazing calf gains were greater (P < 0.05) than bale-fed during the first year of the study but gains were similar during the second year. Greater weight gain for windrow calves during the first year was likely due to the presence of high quality regrowth that occurred after hay harvest. Diet samples collected from fistulated windrow animals in December contained 14.6% crude protein (CP) compared to 10.4% for hand-collected samples of windrows (P < 0.05). Crude protein content of windrow- and baled-stored forage was similar (10.6%, P > 0.05) during all sampling months (September-February). Crude protein content of standing (stockpiled) forage declined to 5.7% by February. Acid detergent fiber (ADF) and neutral detergent fiber (NDF) were similar between windrow and standing storage treatments during all months and higher than bales from November through February. Herbage yield was 20% less in the area directly covered by windrows the previous fall and winter compared to the control (P < 0.05). However, only about 9% of the total area of a pasture is affected by windrow-coverage when 1-m wide windrows are created 11 m apart, resulting in an overall herbage yield reduction of 1.5%. Total forage production costs for the bale-fed strategy were about 63 ha(-1) (37%) higher than windrow grazing due to baling and bale moving costs. Feed costs averaged 0.16 head(-1) day(-1) for windrow and 0.30 head(-1) day(-1) for the bale strategy. When production data were applied to market prices for the previous 7 years, the mean net return ha(-1) for windrow exceeded the net return for the bale strategy by about 93 and the net return for a strategy that directly sold the hay by 174.
Day and night grazing by cattle in the Sahel
Authors: Ayantunde A. A. , Fernández-Rivera S. , Hiernaux P. H. ,   Society for Range Management
Published: March 2016

The influence of night grazing on feeding behavior, nutrition and performance of cattle was studied. Twenty-four steers weighing 367 kg (SD = 76) grazed either from 0900 to 1900 (day grazers), 2100 to 0700 (night grazers) or 0900 to 1900 and 2400 to 0400 (day-and-night grazers) during 13 weeks. Four esophageally fistulated steers were used in a cross-over design to sample the diet selected during the day and at night. No differences (P > 0.05) were observed in the diet selected in the day or at night. As the season progressed the fiber components of the diet increased (P < 0.01) significantly while nitrogen and in sacco dry matter disappearance declined (P < 0.01). Actual grazing time (min day(-1), SE = 16) were 352, 376, and 476 for day, night, and day-and-night grazers, respectively. Day-and-night grazers had a higher intake of organic matter than either day or night grazers. Night grazers had the lowest forage intake and also the slowest rate of consumption. Steers that grazed in the night had the lowest water intake: 22.7 liter day(-1) (SE = 1.5) in week 4; 19.9 liter day(-1) (SE = 1.1) in week 8. Average weight changes (g day(-1), SE = 62) were -435, -548 and -239 for day, night, and day-and-night grazers, respectively. These results show that during the dry season, grazing exclusively in the night cannot substitute for day time grazing, but that it is rather complementary to the latter. Timing (day or night) of grazing did not affect diet selection but nocturnal grazing decreased the need for water.
Seed longevity and seeding strategies affect sagebrush revegetation
Authors: Booth D. T. ,   Society for Range Management
Published: March 2016

Three hypotheses were tested relating to Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis (Beetle and Young) revegetation on coal-mined land in Wyoming: (1) that fourwing saltbush (Atriplex canescens (Pursh) Nutt.) seeded > 2.2 kg pure live seed (pls)/ha would exclude sagebrush, (2) the contrasting view that the saltbush, as a "pioneer plant", facilitated sagebrush stand development [by promoting beneficial soil microbiological activity], and (3) that sagebrush stand development would be greater on fresh-stripped, than on stored, topsoil. The hypotheses were tested by comparing stand development on field plots: 1) seeded to sagebrush in February 1992, and March 1993; 2) fallowed in 1992, and sagebrush seeded in March 1993; 3) seeded to 'Wytana' fourwing saltbush in November, 1991, with sagebrush over-seeded in March, 1993, and; 4) no seeding. The experimental design was a randomized complete block with split plots of stored and fresh-stripped topsoil and with 3 replications. New sagebrush were detected annually through 4 post-seeding spring counts. Seed efficiency was affected by seeding strategy, but efficiency, density, and height were not affected by topsoil source. Proximity to saltbush did not affect sagebrush heights. The results imply that a 'Wytana' density less than or equal to 5 seedlings/m2 is unlikely to deter or promote development of the sagebrush stand, but it will significantly increase total-shrub seed efficiency and density. Seeding strategies, particularly pre-sowing fallow and mixed-species seedings, will likely have a greater influence on sagebrush revegetation than will topsoil source when topsoils are handled as they were in this study.
Drought and grazing: IV. Blue grama and western wheatgrass
Authors: Eneboe E. J. , Sowell B. F. , Heitschmidt R. K. ,   Society for Range Management
Published: March 2016

An understanding of the impacts of grazing during and following drought on rangeland ecosystems is critical for developing effective drought management strategies. This study was designed to examine the effects of drought and grazing on blue grama [Bouteloua gracilis (H.B.K) Lag. ex Griffiths] and western wheatgrass [Pascopyrum smithii Rydb. (Love)] tiller growth dynamics. Research was conducted from 1993 to 1996 at the Fort Keogh Livestock and Range Research Laboratory located near Miles City, Mont. An automated rainout shelter was used during 1994 to impose a severe late spring to early fall (May to October) drought on 6 of twelve, 5- x 10-m non-weighing lysimeters. Twice replicated grazing treatments were: 1) grazed both the year of (1994) and the year after (1995) drought; 2) grazed the year of and rested the year after drought; and 3) no grazing either year. Drought had minimal impact on tiller relative growth rates of plants grazed twice, although it reduced (P less than or equal to 0.01) rates of axillary tiller emergence for blue grama (79%) and western wheatgrass (91%). Defoliation periodically increased relative growth rates (P less than or equal to 0.05) and tiller emergence (P less than or equal to 0.01) of both species. Neither drought nor grazing affected tiller densities or tiller replacement rates of either species nor did they affect productivity of blue grama. Drought, however, reduced (P less than or equal to 0.01) productivity of western wheatgrass 50% in 1994 whereas grazing reduced productivity (P less than or equal to 0.01) by 46% in 1994 and 69% in 1995. Moderate stocking levels (40-50% utilization) during and after drought did not adversely affect the sustainability of these dominant native grasses.
Perspectives on water flow and the interpretation of FLIR images
Authors: Larson S. L. , Larson L. L. , Larson P. A. ,   Society for Range Management
Published: March 2016

Airborne infrared thermal radiography has been proposed as a tool which may be used to monitor the water temperature along the network of streams and rivers which compose a watershed. The proponents of this method correlate vegetative shadows on a stream channel with reduced infrared radiation (IR) reception in the radiographic data to suggest that the water temperature is reduced in such areas. Two methods are employed to demonstrate that this interpretation of the data is in error. First, the fundamental principles of thermodynamics are employed to show that if the stream is in fact flowing, the water affected by any cooling process cannot remain in the vicinity where it was cooled. Second, temperature data taken from a stream channel are used to show that the water flowing in the channel is essentially unaffected by the patterns of vegetative shade on the surface of the channel.
Cull cow management and its implications for cow-calf profitability
Authors: Little R. D. , Williams A. R. , Lacy R. C. ,   Society for Range Management
Published: March 2016

Selling culled breeding livestock is often viewed as "just another chore." Most cull sales are made in the fall, after calves are weaned and cows are pregnancy checked and open. Since cull cow sales comprise from 15 to 30% of a cow-calf enterprise's gross revenue, perhaps they should be viewed as a potential profit center. This paper uses enterprise budgets and sensitivity analyses to illustrate cull cow management strategies that overcome certain physical and economic factors that limit the profitability of fall cow sales. The key limiting physical factor is often poor body condition, which results from the combined effect of lactation and deteriorating forage quality. The key economic factor is a seasonal price low, generated by a large beef supply in the fall. The results suggest potential, with adequate, low-cost feedstuffs, to increase net returns by properly managing cull breeding stock. In only 1 year during the 10-year period, 1990-1999, was selling cull cows in the fall the more profitable option. Over that time period, the net present value of spring cull sales averaged about 30 per cow more than selling cull cows in the fall.
Nutritional quality of forages used by elk in northern Idaho
Authors: Alldredge M. W. , Peek J. M. , Wall W. A. ,   Society for Range Management
Published: March 2016

The nutritional quality (digestible energy, crude protein, and minerals) of 7 known elk (Cervus elaphus Linnaeus) forages was assessed at 4 different time periods from May to November. Species evaluated were elk sedge (Carex geyeri Boott), Kentucky bluegrass (Poa pratensis Linnaeus), western goldthread (Coptis occidentalis Nuttall), clover (Trifolium repens Linnaeus), service-berry (Amelanchier alnifolia Nuttall), redstem ceanothus (Ceanothus sanguineus Pursh), and Scouler willow (Salix scouleriana Barratt). Mineral concentrations generally met estimated requirements for elk in all seasons, except sodium remained below requirements in all seasons. Crude protein in most plant species sampled was adequate for adult gravid or lactating cows throughout the year, although concentrations in graminoids fell below requirements during August. Forage provided adequate digestible energy for gravid or lactating cows only during May, indicating potential deficiencies in summer and autumn. Elk must be selective of plant parts, plant taxa, and foraging habitat to gain adequate nutrition. In this area, summer and fall forage quality may be critical to lactating cow elk.
Journal of Range Management, Volume 55, Number 3 (May 2002)
Authors:   Society for Range Management
Published: March 2016

Complete digitized issue.
Drought and grazing: II. Effects on runoff and water quality
Authors: Emmerich W. E. , Heitschmidt R. K. ,   Society for Range Management
Published: March 2016

Understanding the interacting effects of drought and grazing on runoff, erosion, and nutrient transport is essential for improved rangeland management. Research was conducted at the Fort Keogh Livestock and Range Research Laboratory located near Miles City, Mont. using 12, non-weighing lysimeters for 3 years. During years 1 and 3, no drought treatment was imposed. For year 2, one half of the lysimeters were covered to implement a drought treatment. The 3 grazing treatments were ungrazed, grazed during but not after drought, and grazed during and after drought. Runoff, sediment yield, and an array of nutrients in the runoff water were measured from the lysimeters. First year base line data with no grazing or drought treatments applied indicated no significant differences among lysimeters. Below normal precipitation occurred during year 2, resulting in no runoff from the drought treatment and negated the "non-drought" control. This prevented a direct assessment of the interaction among the drought and grazing treatments for this year. The drought treatment did produce significant reductions in water, sediment, and nutrient yield. No grazing impact was observed during year 2. The third year with more normal precipitation, there was a trend toward increased runoff, sediment, and nutrient yield from the second year drought treatment lysimeters. In the third year, both grazing treatments showed significantly greater runoff, sediment, and nutrient yield than the ungrazed treatment. Runoff and sediment yield tended to increase from the combination of drought and grazing treatments. The observed increases in runoff and sediment and reduced water quality from the drought and grazing treatments were measured against controls and when compared to the natural variability and water quality standards, they were concluded to be minimal.
Snakeweed: Poisonous properties, livestock losses, and management considerations
Authors: McDaniel K. C. , Ross T. T. ,   Society for Range Management
Published: March 2016

Snakeweeds (broom, Gutierrezia sarothrae (Pursh) Britt Rusby); and threadleaf, G. microcephala (DC.) Gray) fall into that class of poisonous weeds that seldom cause direct livestock losses because they are highly unpalatable and animals rarely consume large quantities of plant material. However, when snakeweed becomes dominant on rangeland and retards growth of desirable forage, then indirectly it becomes a serious hazard to animal health. Confined and rangeland feeding trials conducted at New Mexico State University with cattle and sheep have failed to elicit reproductive failure with elevated snakeweed dosages. Snakeweed was shown to impair certain reproductive functions such as pituitary responsiveness to luteinizing hormone, and caused mild hepato-renal toxicity. Under rangeland conditions, livestock grazing in areas dominated by snakeweed reportedly have more serious problems, such as abortion. A commonality between confined feeding trials and rangeland grazing trials is that in the presence of snakeweed, animals typically display symptoms associated with a low-plane of nutrition such as lack of gain, emaciation, and occasional death. To reduce snakeweed dominance and improve range condition, management interventions such as herbicide or fire control may be necessary. Complicating the decision regarding snakeweed control is the uncertainty about treatment life and whether this relatively short-lived perennial weed might be eliminated by natural causes. Knowing the snakeweed population pattern in a given area greatly enhances management decisions.
Reproductive losses to poisonous plants: Influence of management strategies
Authors: Panter K. E. , James L. F. , Gardner D. R. ,   Society for Range Management
Published: March 2016

Poisonous plants that impair normal reproductive functions in livestock include Veratrum californicum Durand, lupines, ponderosa pine (Pinus ponderosa Dougl.), broom snakeweed (Gutierrezia sarothrae (Pursh) Britt. Rusby), locoweeds (Astragalus and Oxytropis spp.), selenium-containing forages, phytoestrogenic plants, endophyte-infected grasses and others. In this review we focus on lupines, locoweeds and ponderosa pine needles to demonstrate the broad and diverse effects that poisonous plants have on reproduction. Certain lupines (Lupinus spp.) contain quinolizidine and piperidine alkaloids that are fetotoxic and when grazed by pregnant cattle during specific stages of gestation induce skeletal birth defects and cleft palate, "crooked calf disease". Poison-hemlock (Conium maculatum) and some Nicotiana spp. contain similar alkaloids and induce identical birth defects in cattle, pigs, goats and sheep when ingested at certain stages of gestation. Locoweeds (species of the Astragalus and Oxytropis genera containing the indolizidine alkaloid swainsonine) interfere with most processes of reproduction when grazed for prolonged periods of time. Animals can recover normal reproductive function if withdrawn from locoweed grazing before severe poisoning occurs. While most animals may recover reproductive function, permanent neurological deficits may preclude normal reproductive behavior. Ponderosa and lodgepole pine needles (Pinus spp.) cause abortion in cattle when grazed during the last trimester of gestation. The specific chemical constituents responsible for the abortions belong to a class of compounds called labdane resin acids, including isocupressic acid (ICA), succinyl ICA, and acetyl ICA. Basic management recommendations to reduce reproductive losses to poisonous plants include: (1) keep good records; (2) know what poisonous plants grow on ranges and understand their effects; (3) develop a management plan to provide for alternate grazing in poisonous plant-free pastures during critical times; (4) provide for balanced nutrition, including protein, energy, minerals and vitamins; (5) maintain a good herd health program; (6) integrate an herbicide treatment program to reduce poisonous plant populations or to maintain clean pastures for alternate grazing; and, (7) manage the range for maximum forage production.
Risk management to reduce livestock losses from toxic plants
Authors: Pfister J. A. , Provenza F. D. , Panter K. E. ,   Society for Range Management
Published: March 2016

Risk of livestock losses to poisonous plants can be reduced on many ranges through prudent management based on application of existing knowledge. Poisonous plants can be categorized using both acceptability to livestock and a plant's toxic potential. Acceptability encompasses forage qualities such as taste and chemistry (i.e., nutrient and toxin concentrations) and postingestive feedback from an animal's daily and long-term (e.g., body condition) nutritional and toxicological state. Toxic potential reflects aspects of plant chemistry, including seasonal or other changes in concentration or functionality of the toxin(s), and type of toxicity (i.e., acute or chronic). Persistent livestock losses to poisonous plants may indicate that ranges are over-grazed or improperly managed. Aggressive management schemes that employ high stocking rates and grazing intensities may yield greater returns, but may also increase risk if poisonous plants are present. Plants may be ranked according to toxicity and acceptability. Six interrelated categories of plants are discussed: 1) always toxic and acceptable to livestock; 2) always toxic and not acceptable; 3) always toxic and acceptable at certain times; 4) toxic only at certain times and acceptable to livestock; 5) toxic at certain times and unacceptable; and 6) toxic at certain times and acceptable at certain times. Each category involves differing risk and uncertainty. Within this management matrix, strategies for dealing with specific poisonous plants can be customized depending on how much and when the plant is eaten by livestock, and when the plant is most toxic.
Establishment of silver sagebrush in the Northern Mixed Prairie
Authors: Romo J. T. , Grilz R. W. ,   Society for Range Management
Published: March 2016

Interest has been expressed in using silver sagebrush (Artemisia cana Pursh ssp. cana) in restoring the Northern Mixed Prairie in Saskatchewan. The objectives of this study were to determine the effects of seedbed manipulation treatments and autumn or spring sowing on establishment of silver sagebrush on sites previously seeded to native, perennial grasses. Seeds (achenes) were sown by broadcasting at 20 pure live seeds m(-2). Seedling emergence ranged from 5 to 6% of seeds sown. Most seedlings emerged in May and June; no seedlings emerged after July or in the second year after planting. Seventy-four to 84% of emerging seedlings survived the first growing season with 96 to 98% of these seedlings establishing. On upland sites, seedling emergence (1.1 seedlings m(-2) SE +/- 0.1) and establishment (0.9 seedlings m(-2) SE +/- 0.1) were similar between autumn and spring sowing and among seedbed manipulation treatments. On lowland sites, seedling emergence (1.4 seedlings m(-2) SE+0.2) and establishment (0.8 seedlings m(-2) SE +/- 0.2) were similar between autumn and spring seeding. Density of seedlings establishing was greatest when the seedbed was tilled. Establishment of silver sagebrush appears primarily limited by low numbers of seedlings emerging, indicating very specific safe site requirements for this shrub. Drastic disturbance of the seedbed is not required to establish silver sagebrush in established stands of perennial grasses. Sowing silver sagebrush in late autumn when temperatures are consistently below 0 degrees C or in early spring immediately after snowmelt is recommended.
Halogeton grazing management: Historical perspective
Authors: Young J. A. ,   Society for Range Management
Published: March 2016

Halogeton [Halogeton glomeratus (Bieb.) C. A. Mey], is a fleshy, annual, herbaceous species that was accidentally introduced into the western U.S. during the 20th century. Because it is highly poisonous to sheep (Ovis aries), this rather diminutive herb became the center of attention for biological research on Intermountain rangelands during the 1950s. Grazing management for halogeton involves procedures to prevent accidental poisoning of the grazing animals, and management to encourage the density and vigor of competing perennial vegetation to biologically suppress halogeton. Halogeton became most abundant in salt desert rangelands and the lower elevation portions of the sagebrush (Artemisia)/bunchgrass zone. In the sagebrush zone the introduced perennial crested wheatgrass [Agropyron desertorum (Fisher) Schultes] was widely planted to both suppress halogeton and to provide alternative forage for livestock. In the salt deserts, the management of native chenopod shrubs was the key to suppressing halogeton. The key species in salt deserts was the highly preferred semi-woody species winterfat [Krascheninnikova lanata (Pursh) A. D. J. Meeuse Smit]. In many parts of the Intermountain region, halogeton has declined in importance because of the reduced importance of the range sheep industry and improved range condition. In the south central Great Basin, halogeton is still considered a serious problem.
Density and reproductive success of Florida grasshopper sparrows following fire
Authors: Delany M. F. , Linda S. B. , Pranty B. ,   Society for Range Management
Published: March 2016

Information on the response of the endangered Florida grasshopper sparrow (Ammodramus savannarum floridanus Mearns) to range management, especially prescribed fire, is needed to determine conservation strategies. Intensive management of grasslands for cattle grazing and conversion of grassland to other agricultural use is considered the greatest threat to the sparrow. Territory spot-mapping and estimates of reproductive success were examined in relation to time post-burn in managed cattle pastures at Avon Park Air Force Range, Highlands County, Florida from 1997-1999. We tested the hypothesis that sparrow density and reproductive success did not depend on time following fire. Contrary to previous work, there was no evidence that Florida grasshopper sparrow territory density depended on years post-burn (P = 0.842). The probability of reproductive success was significantly higher 0.5 year post-burn than at 1.5 years post-burn (P < 0.05) and 2.5 years post-burn (P < 0.01). No other significant differences were observed among years post-burn (P > 0.27 for each pairwise comparison between years). No simple trend or highly significant polynomial relationship between reproductive success and territory density was indicated (P > 0.41). Compared to other subspecies, Florida grasshopper sparrows exhibited relatively low density (0.22 territories/ha or less) and reproductive success (20%). Our results suggest increased reproductive success at a population level 0.5 year following fire, and did not suggest an association between territory density and individual reproductive success. Additional information is needed on the effects of seasonality of fire on Florida grasshopper sparrows.
Monitoring a half-century of change in a hardwood rangeland
Authors: Heise K. L. , Merenlender A. M. ,   Society for Range Management
Published: March 2016

Changes in rangeland species composition can effect forage quality, ecosystem function, and biological diversity. Unfortunately, documenting species compositional change is difficult due to a lack of accurate historic records. We took advantage of herbarium records dating from the early 1950's to reconstruct the past flora of a 2,168 ha hardwood rangeland in Mendocino County, California, and then compared this to the current flora of the site. An inventory of vascular plants conducted from 1996 to 2001 added 44 native and 15 non-native species bringing the total number of species and infraspecific taxa at the study site to 671. Of the original 612 species recorded prior to this study, 34 native and 1 non-native species could not be relocated. The percentage of non-native species increased from 19% in 1952 to 23% in 2001. Based on estimates from the early 1950's, mid 1980's, and 1996 to 2001, at least 13 non-native species have increased in abundance, while some native species have decreased. Livestock grazing, competition with invasive species, conversions to different vegetation types, and transportation of propagules into the site by vehicles and livestock, combined with the difficulty of relocating rare species, are posed as the most likely causes for the documented changes.
Early weaning and length of supplementation effects on beef calves
Authors: Pordomingo A. J. ,   Society for Range Management
Published: March 2016

Early weaning of calves can improve reproduction of beef cows, and would be of no detriment to calf growth if the diet is adequate. Digestible energy intake could be limiting, however, when calves are weaned on forage. Performance of calves weaned at 70 days (early weaning) and 172 days (normally weaning) of age were compared. Calves from 2 locations in Argentina, Anguil, and Chacharramendi, were distributed in 14 groups and half were weaned. Early-weaned calves were pen fed a 50% concentrate-50% alfalfa hay diet for 12 days, followed by grazing on alfalfa for 150 days. During the first 90 days on pasture, early-weaned calves were group supplemented (1.2 % body weight (BW, DM basis). Calves from Anguil did not differ (P = 0.068) in average daily gain (ADG). In contrast, early-weaned calves from Chacharramendi gained faster than normally-weaned calves (P 0.01). In a second experiment, 108 calves were classified into 3 age groups on day 0 of trial (AGE1 = 109 +/- 2.2 days of age, AGE2 = 91 +/- 1.6 days of age and AGE3 = 75 +/- 3.8 days of age). Two thirds of the calves were weaned (early-weaned calves) the same day and the remaining third was returned to their dams (normally-weaned calves). Two feeding treatments were imposed on the early-weaned calves: S15 = supplement during the first 15 days on pasture (1% body weight, DM basis), and S45 = supplement during the first 45 days. Early-weaned calves grazed on an alfalfa pasture for 136 days. Calves from the normally-weaned group remained with their mothers until weaning onto pasture on day 87 of the study. Normally-weaned calves were the heaviest (P < 0.05) at the end of trial. Differences in body weight between early weaning ages increased as the supplementation period decreased. Calves that were weaned at 75 days of age and fed supplement for only 15 days had the lowest (P < 0.05) overall ADG and final body weight. Overall results suggested that early weaning favors reproduction of thin cows, and early-weaned calves can be placed on good-quality pasture with no detriment of growth if energy supplement is provided.
Calibrating fecal NIRS equations for predicting botanical composition of diets
Authors: Walker J. W. , McCoy S. D. , Launchbaugh K. L. ,   Society for Range Management
Published: March 2016

The objectives of this study were to investigate the use of near infrared spectroscopy (NIRS) of fecal samples for predicting the percentage of mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana (Rydb) Beetle) in sheep diets and to quantify the limitations of using NIRS of fecal samples to predict diet composition. Fecal material from a sheep feeding trial with known levels of sagebrush and several background forages was used to develop fecal NIRS calibration equations validated with fecal material from 2 other sheep feeding trials with known levels of sagebrush in the diets. The 1996 calibration trial varied the level of sagebrush, alfalfa, and grass hay in the diets. The 1998 trial compared frozen to air-dried sagebrush. The Wyoming trial was a metabolism study using frozen sagebrush. Trials used different levels of sagebrush varying from 0 to 30% of the diet in increments of 4 to 10 percentage points. Internal validation of the 1996 trial with a subset of the samples not used for calibration showed that when predicted samples are from the same population as the calibration samples, this procedure can accurately predict percent sagebrush (R2 = 0.96, SEP = 1.6). However, when predicted samples were from a different population than calibration samples, accuracy was much less, but precision was not affected greatly. Low accuracy was caused by a compression of the range of data in the predicted values compared to the reference values, and the predicted sagebrush levels in the diet should be considered to represent an interval scale of measurement. Modified partial least squares regression resulted in better calibration than stepwise regression, and calibration data sets with only high, low, and no sagebrush resulted in calibrations almost as good as data sets with several intermediate levels of sagebrush. High values of the H statistic were related to low precision but did not affect the accuracy of predictions. We believe the interval scale of measurement will contain sufficient information for the purpose of addressing many questions on rangelands.
Sample numbers for microhistological estimation of fecal vizcacha diets
Authors: Bontti E. E. , Bóo R. M. ,   Society for Range Management
Published: March 2016

Precise estimates of diet composition are useful to assess herbivores impact on rangelands and to make management decisions. Since the variability within- and between-samples affect precision of estimates on diet studies, we studied this variability in diets of the rodent vizcacha (Lagostomus maximus Blainv.). We analyzed fecal pellets using a microhistological technique and we estimated the number of samples and subsamples required to achieve given confidence levels. Diets of this herbivore, which is thought to compete with cattle for forage, were studied in November 1994, May, July, and October 1995 in a mixed shrub-grassland community of the southern caldénal in central Argentina. Most grasses, the main components of the diets (> 80%), were estimated with high precision (confidence interval: CI = 10%, p = 0.05) by observing 14 samples and 5 slides per sample. Forbs (5-6%) and shrubs (12%) were estimated with this same number of samples and slides, but yielded a lower level of precision (CI = 20%, p = 0.10). Although our results may not be directly applicable to other vegetation or herbivores, the procedures may be used in other situations to improve precision of diet estimates through microhistological analysis of feces.
Quality and persistence of forages in the Northern Great Plains
Authors: Haferkamp M. R. , Grings E. E. , Heitschmidt R. K. ,   Society for Range Management
Published: March 2016

Integrating use of seedings of perennial cool-season grasses with native range is used to increase available forage and for maintaining a high plane of nutrition for grazing livestock. Our goal was to evaluate performance of yearling cattle and stand persistence of 3 released wheatgrass cultivars. Twice replicated 3-ha pastures were seeded to 'Rosana' western wheatgrass [Pascopyron smithii (Rydb.) A. Love], 'Luna' pubescent wheat-grass [Elytrigia intermedia (Host) Nevski], and 'Hycrest' crested wheatgrass ([Agropyron cristatum (L.) Gaertn.] ssp. desertorum (Fisch. ex Link) A. Love) in autumn 1994. Yearling steers (n = 8) grazed from 9 May to 12 June 1997 and 24 April to 15 June 1998. Yearling heifers grazed from 27 April to 18 June 1999. Hycrest produced the largest herbage standing crop in spring 1997 (912 kg ha(-1)) and 1998 (1,223 kg ha(-1)) (P < 0.05), but by spring 1999 standing crops averaged 656 kg ha(-1), and cultivars were not significantly different. Digestible organic matter standing crop did not differ among pastures of seeded species, but declined (P < 0.05) from May to June each year. Crude protein standing crop varied among cultivars (P < 0.05) in April and May 1998 and May 1999; however, no clear trends emerged. Crude protein standing crops consistently declined from April-May to June. Average daily gains were similar among cultivars in 1997, but greater (P < 0.05) on Hycrest (1.28 kg day(-1)) than Rosana (1.03 kg day(-1)) in 1998. Gains on Hycrest (0.74 kg day(-1)) and Rosana (0.78 kg day(-1)) were greater (P < 0.05) than on Luna (0.52 kg day(-1)) in 1999. These findings show in some years, Hycrest provided more forage in spring than Rosana, and will allow an increase in livestock numbers. Based on the encroachment of invading species, persistence of Luna is marginal of the 335-mm precipitation zone in the Northern Great Plains.
Free-choice grazing of native range and cool-season grasses
Authors: Karn J. F. , Ries R. E. ,   Society for Range Management
Published: March 2016

A grazing system which allows cattle to select a season-long diet more nearly meeting their nutrient requirements should facilitate optimal weight gains. A study was conducted near Mandan, N. D. comparing season-long weight gains of yearling steers free-choice grazing on composite pastures containing equal sized plots of 'Nordan' crested wheatgrass (Agropyron desertorum) (Fisch. Ex. Link) Schult.), 'Rodan' western wheatgrass (Pascopyrum smithii (Rydb.) Löve), 'Lincoln' smooth bromegrass (Bromus inermis Leyss.), and native range, to pastures containing the individual pasture types alone. The study was initiated in mid-May and terminated in early October each year from 1995-1997. Pastures were grazed at a stocking rate of 1.9 ha per steer for 147 days or 1.7 AUM ha(-1). Steer behavior on composite pastures was recorded every 10 min. from dawn to dusk 2 days per week each summer. In 1997, forage samples were clipped for chemical analysis at 4-week intervals from all pasture types either within composite pastures or as individual pasture types. Only in 1996 were daily gains of steers on the free-choice treatment different (P < 0.10) from all other treatments. Over the 3-year study, daily gains for steers on the free-choice treatment (1.11 kg) were statistically equal to steers on smooth bromegrass (1.04 kg) and western wheatgrass (1.00 kg) and were significantly greater than daily gains on native range (0.98 kg) and crested wheatgrass (0.97 kg). Steers tended to spend a greater percentage of observation time grazing smooth bromegrass than the other 3 pasture types, especially early in the grazing season. The period of maximum grazing preference for the other pasture types was late in the season in 1995 and 1996 for crested wheatgrass, in mid-season in 1996 for native range, and late in the season in 1997 for western wheatgrass. Chemical analysis of forage samples collected in 1997 show that smooth bromegrass had the highest crude protein and in vitro dry matter digestibility, and the lowest neutral detergent fiber at all 3 summer grazing periods. Forage quality data and the preference of steers for smooth bromegrass help to explain why steers on this treatment had excellent daily gains, especially during early and mid-season.
Vegetation dynamics following seasonal fires in mixed mesquite/acacia savannas
Authors: Owens M. K. , Mackley J. W. , Carroll C. J. ,   Society for Range Management
Published: March 2016

Fires were once a natural part of most savanna ecosystems, but lack of fine fuel and an active suppression policy have changed fire frequency and seasonality. Re-introducing fires to these systems has been touted as a cost-effective means to reduce woody cover while increasing herbaceous growth. We compared the effects of single, recurring annual, and biennial fires on the vegetation dynamics of a mixed mesquite/acacia (Prosopis/Acacia) savanna in southern Texas. Fires were conducted either during the growing season or the dormant season from 1991 through 1995. Some of the fire treatments were statistically unreplicated to permit a sufficient plot size for natural fire behavior. All plots showed a successional trajectory from short-grasses towards mid-grasses regardless of the fire season or frequency. The population size structure of perennial grasses was unaffected by the fires, with the basal area of most plants being less than 25 cm2. Forb diversity was high with over 100 different species identified in the experimental area. Forb composition, however, was unaffected by either the season or frequency of fire, but was related to the year of observation. Shrubs in this community typically sprout after disturbance, so little mortality was expected. The only observed mortality was of small shrubs or saplings (diameter < 3 cm) and of large trees which had woodrat (Neotoma micropus) nests at the base. Reintroducing growing season fires into mesquite/mixed acacia shrublands did not conclusively alter plant community composition. Burning during the growing season when environmental conditions were hotter and drier did not accelerate succession toward grass-dominated communities.
A robust model for estimating standing crop across vegetation types
Authors: Vermeire L. T. , Ganguli A. C. , Gillen R. L. ,   Society for Range Management
Published: March 2016

Some recent investigations have shown the visual obstruction (VO) measurement method to be an effective means of estimating herbage standing crop non-destructively in tallgrass prairie. Although the method is rapid and inexpensive, visual obstruction models have been limited to tallgrass prairie and sandhills range types. Our primary objective was to evaluate the relationships between visual obstruction and standing crop in shortgrass plains and mixed prairie. Secondly, we wanted to determine whether these models could be integrated with tallgrass prairie models without appreciable losses in prediction capabilities. We conducted 44 trials on non-burned sites with various levels of grazing pressure. Each trial was composed of 20 randomly selected plots and served as 1 experimental unit to represent pasture-level standing crop estimation. Visual obstruction readings were taken from a modified Robel pole placed centrally at the back of 0.1-m2 quadrats and vegetation was clipped to estimate standing crop. Trial standing crop was regressed on visual obstruction and models were compared among range types. Visual obstruction explained 91 and 89% of the variation in shortgrass plains and mixed prairie standing crop, respectively. A single visual obstruction model effectively estimated herbage standing crop across range types and produced a coefficient of determination of 0.93. Although greater precision may be obtained from models developed for specific sites, the ability of a single visual obstruction model to predict standing crop across years, management schemes, and range types indicates visual obstruction models may be successfully employed on a regional basis.