• Botanical and Chemical Composition of Esophageal and Rumen Fistula Samples of Sheep

      Rice, R. W.; Cundy, D. R.; Weyerts, P. R. (Society for Range Management, 1971-03-01)
      Bifistulated wethers (esophageal and rumen) were used to collect samples of the diet while grazing shortgrass native range. Rumen samples were obtained by grab sampling rumen contents. The rumens were not evacuated prior to sampling. The esophageal and rumen grab samples were different botanically. There were fewer forbs and more grasses found in rumen samples. The nitrogen content of rumen samples was higher than that of esophageal samples. Rumen samples were lower in in vitro dry matter digestibility than esophageal samples. Rumen grab samples cannot be expected to yield quantitative botanical information on grazing animals diet or on nitrogen content and dry matter digestibility.
    • Control of Larkspur with Herbicides Plus Nitrogen Fertilizer

      Binns, W.; James, L. F.; Johnson, A. E. (Society for Range Management, 1971-03-01)
      Past attempts using herbicides to control larkspur (Delphinium barbeyi), one of the most serious poisonous plant problems to cattle in the Western United States, have been less than satisfactory. Preliminary research reported herein suggests that 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) plus ammonium sulfate placed around the base of the plant or urea and 2,4,5-T sprayed on the plant may give good control of larkspur with a single treatment during any stage of growth. Some results also indicate that nitrogen fertilizer alone may be an effective control for larkspur.
    • Correlation of Weather and Fuel Variables to Mesquite Damage by Fire

      Britton, C. M.; Wright, H. A. (Society for Range Management, 1971-03-01)
      Twenty-four 10-acre plots were burned in the Southern Mixed Prairie of Texas under a variety of weather and fuel conditions to determine their effect on ignition, burndown, and mortality of mesquite that had been top-killed by spraying. The number of trees that ignited on each plot varied from 33.6 to 94.9% of the total, whereas the number of trees that burned down varied from 14.4 to 89.1%. Mortality varied from 0 to 24%. Large trees were easier to burn down and kill than small trees. Equations that incorporate wind speed, relative humidity, and total fuel were developed to predict ignition and burndown.
    • Cow-Calf Response to Stocking Rates and Grazing Systems on Native Range

      Kothmann, M. M.; Mathis, G. W.; Waldrip, W. J. (Society for Range Management, 1971-03-01)
      Studies of grazing management for cow-calf operations on native range have been conducted on the Texas Experimental Ranch since 1960. Three stocking rates and three grazing systems were evaluated. Calf production was greater from the deferred-rotation grazing systems than from continuous grazing at the same stocking rate. Heavier stocking rates reduced calf production per animal unit slightly, but production per acre increased significantly. The net returns per animal unit were greatest from the Merrill system, stocked at a moderate rate, and the net returns per acre were greatest from heavy continuous stocking. The optimum stocking rate for this range appeared to be between 40 and 50 animal units per section and it was profitable to use the Merrill grazing system./Se llevó a cabo un estudio en el rancho experimental de Texas cerca de Throckmorton, Texas, E.U.A., comprendiendo un período de diez años. Los tratamientos fueron: pastoreo todo el año a tres diferentes cargas de animales: pesado (12.8 acres por vaca), moderado (20.8 acres por vaca), ligero (28.4 acres por vaca) y dos diferentes sistemas de pastoreo con rotación a la carga moderada. La producción de becerras por vaca fué mas alta para los sistemas de pastoreo con rotación que para el pastoreo por todo el año a la misma carga moderada. La producción por vaca fué menor en el tratamiento de pastoreo todo el año a la carga pesada pero la producción por acre fué mayor que en todos los otros tratamientos. También el ingreso neto por acre. El ingreso neto por vaca fué mayor en el cuarto potrero rotación llamado Sistema de Merrill. El coeficiente de agostadero óptimo fué entre 12.5 y 15 acres por unidad animal.
    • Effect of Astragalus tenellus on Sheep

      James, L. F. (Society for Range Management, 1971-03-01)
      Feeding trials involving Astragalus tenellus demonstrated that this plant is not toxic to sheep.
    • Efficiency of Combining Improvement Practices that Increase Steer Gains

      Shoop, M. C.; McIlvain, E. H. (Society for Range Management, 1971-03-01)
      Contrary to general expectations, four improvement practices used in combination increased yearlong gain per steer as much as the sum of the practices used alone. The improvement practices studied were moderate grazing, additional winter cake, late-summer cake, and stilbestrol. The basic practice was heavy grazing. The 100% efficiency of gain obtained with the combined practices indicates that an improvement practice should produce about the same increase in gain regardless of the number of other improvement practices used on a ranch or in an experiment./Cuatro diferentes estudios anteriores en la estación experimental de Planicias de Sur, Woodward, Oklahoma, E.U.A., mostraron cuatro diferentes prácticas que aumentan las ganancias de novillos en pastoreo. Estas son: 1) Pastoreo con carga de 8 acres por novilla contra 6 acres por novilla. 2) Suplementación durante el invierno con harinolina (42% proteína) dando 3 libras por novillo diario en comparación con 1.5 libras por novillo diario. 3) Suplementación de harinolina durante el verano cuando los zacates están secos, cantidad 1 libra por novillo diario. 4) Implantación de 12 mgs. de estilbestrol durante los meses de Noviembre y Mayo. Se encontró en este estudio que las prácticas son aditivas. La aplicación de las cuatro prácticas combinadas aumentaron las ganancis de peso de 92 libras por res que fué igual a la suma de los aumentos por las prácticas aplicadas por separado.
    • Establishment of Subclover in Relation to Nodulation, Time of Seeding, and Climatic Variations

      Jones, M. B.; Lawler, P. W.; Murphy, A. H. (Society for Range Management, 1971-03-01)
      Pellet inoculated subclover (Trifolium subterraneum) seed planted at various autumn dates on a site where effective nodulation was known to be a problem, produced healthy plants when mean ambient air temperature in the 6 weeks following germination was between 49 and 62 F. When mean temperature for the 6-week period was about 45 F, very poor clover stands developed. Seed planted September 10, about one month before a rain, produced a good stand of vigorous clover. This indicated that sufficient viable inoculum had survived in dry soil on the pelleted seed until the rains came. It is recommended that where subclover is adapted, plantings be made in October rather than waiting until after the soil is wet. More vigorous clover grew from seed which was in the ground at the time of the first rain than from seed drilled soon after the rain.
    • Grass Mixtures for Seeding Sagebrush Lands

      Hull, A. C. (Society for Range Management, 1971-03-01)
      Four wheatgrasses were seeded alone and in mixtures in 1945 near Dubois, Idaho. By 1955, fairway wheatgrass had spread by seed to all plots and has remained the most abundant species. Intermediate and pubescent wheatgrasses spread slower, mainly by rhizomes, and by 1967, they were present on all treatments. At the end of 25 years these three species are growing well together. Bluebunch wheatgrass has practically disappeared from the study area.
    • In Vitro Digestibility of Native Grass Hay

      Karn, J. F.; Clanton, D. C.; Rittenhouse, L. R. (Society for Range Management, 1971-03-01)
      Method of storage had a greater effect on the in vitro dry matter digestibility (DMD) of native grass hay than either storage time or date of cutting. The nutritive value of native hay was maintained better by storing it in round bales than by storing it in windrows, bunches or letting it remain standing. The first 60 days in storage was the period when native hay had the greatest loss of nutritive value regardless of storage method. There was an interaction of cutting date and year on DMD. The early cut hay in 1962 had a higher DMD (42.7%) than the late cut hay (40.3%). There was no difference in 1963 (40.6 vs. 40.1%).
    • Light Delays Germination of Alkali Sacaton

      Knipe, O. D. (Society for Range Management, 1971-03-01)
      Exposure of alkali sacaton seeds to light for a few seconds after imbibition delayed germination 24 hr, exposure for 9 to 13 hr delayed germination 28 hr, exposure for more than 13 hr delayed germination 72 hr, and continuous exposure reduced germination 40%.
    • Longevity of Buffel Grass Seed Sown in an Arid Australian Range

      Winkworth, R. E. (Society for Range Management, 1971-03-01)
      Three sets of buffel grass seed with germination percentages of 0.8, 35 and 94 were sown in a spinifex grassland near Alice Springs, N.T., at a depth of 2.5 cm. Replicated batches were recoverd from each set at increasing intervals and their germinability compared to seed kept in laboratory storage. All seed lost dormancy progressively, more rapidly in soil than storage. In the soil natural death of non-dormant seeds was probably concurrent with loss of dormancy, the balance leading eventually to small germination percentages. Values of about 10% were obtained 2-4 years after sowing, the seed with highest germinability at sowing having the shortest span. In storage germination percentages remained above 60. Range seeding of adapted varieties of buffel grass in arid regions with infrequent establishment periods can be attempted with confidence in seed longevity.
    • Measurement of Seasonal Air Temperatures Near the Soil Surfaces

      Fowler, W. B. (Society for Range Management, 1971-03-01)
      A study of the maximum air temperature near the soil surface at 11 grassland locations was made during the summer of 1968 using a simple maximum temperature indicator. Maximum temperatures within the first centimeter above the soil were found to exceed 144 F on a number of these locations. Although the range of indicators was not large enough to include the extremes at all locations, a seasonal pattern was identifiable. Large local differences in near-surface temperatures were frequently observed.
    • Mesquite Twig Girdler: A Possible Means of Mesquite Control

      Ueckert, D. N.; Polk, K. L.; Ward, C. R. (Society for Range Management, 1971-03-01)
      The mesquite twig girdler (Oncideres rhodosticta Bates) was found to inflict considerable damage to mesquite in Texas and may prove to be a valuable biological control agent for this noxious species. Preliminary observations in infested areas indicated that about 90 percent of the mesquite trees had been attacked by the girdler and that about 40 percent of all branches from 0.5 to 2.0 cm in diameter had been girdled.
    • Nature of Phytomer Growth in Blue Grama

      Stubbendieck, J.; Burzlaff, D. F. (Society for Range Management, 1971-03-01)
      The pattern and relative growth rates of the individual phytomers of blue grama were determined. A mature blue grama shoot from the site had an average of 13 complete phytomers. The first six phytomers appeared to be initiated in the growing season prior to the one in which the plant reached maturity. Internodal elongation of over 100 mm in a period of two weeks was not uncommon. In most instances the internodes did not elongate before the sheath and blade reached maximum length. The leaf of the last phytomer was initiated just prior to the middle of June. Mature sheath length varied from 15 mm in phytomer 13 to nearly 80 mm in phytomers 11 and 12. Blade length varied from 4 mm in phytomer 2 to 134 mm in phytomer 10.
    • Nutritive Value of Forage and Diets of Sheep and Cattle from Oregon Subclover-Grass Mixtures

      Bedell, T. E. (Society for Range Management, 1971-03-01)
      During spring-summer over a three-year period, selectivity by both sheep and cattle grazing on subclover-perennial ryegrass and subclover-tall fescue resulted in higher nutritive value of diets than of ungrazed forage. Sheep diets consistently contained more crude protein and had higher in vitro dry matter digestibility than did cattle diets. Both sheep and cattle diets were more digestible under light than under heavy grazing but diet protein levels were inconsistent. In one year stocking rate had no effect on level of protein in the diet and the next year high protein levels were associated with heavy use. Summer vegetative regrowth of tall fescue caused by heavy cattle grazing resulted in levels of dietary protein for cattle similar to those for sheep. The level of dietary protein for sheep exceeded recommended requirements. In the summer, protein levels of cattle diets were near or below requirements except when cattle heavily grazed subclover-tall fescue pastures.
    • Optimum Stand Selection for Juniper Control on Southwestern Woodland Ranges

      Jameson, D. A. (Society for Range Management, 1971-03-01)
      The optimum time for a land improvement investment when both cost and benefits are changing is when the rate of change of benefits equals the rate of change of costs. This principle can be applied to selecting optimum weed-tree stands for control operations where stands are present in a variety of age classes. If the cost of the control method is fixed, older stands with zero rate of tree cover change represent optimal treatment areas, but if the cost of the control method increases with stand age, young stands represent optimal treatment situations.
    • Range Resources of Iceland

      Thorsteinsson, I.; Olafsson, G.; Van Dyne, G. M. (Society for Range Management, 1971-03-01)
      Animal agriculture in Iceland is second only to fisheries. At least half the forage consumed by large herbivorous animals comes from rangelands. During the period June to September most of the sheep and large numbers of unbroken horses graze on mountain ranges where they roam freely in large grazing districts or commons. There is urgent need for land reclamation and range improvement. Only 25% of the country is covered with vegetation, much of which does not provide adequate protection against soil erosion and has low carrying capacity. With increasing population and demands upon rangelands for food production, an aggressive program of rangeland improvement and management, supported by adequate research, is essential.
    • Seed Dispersal in Relation to Rodent Activities in Seral Big Sagebrush Communities

      La Tourrette, J. E.; Young, J. A.; Evans, R. A. (Society for Range Management, 1971-03-01)
      Heteromyid rodents play an active role in the dispersal of caryopses and seeds of herbaceous species in degraded big sagebrush communities. Collections of caryopses of downy brome, deposited in caches, influence the dynamics of the grass population and the diet of animals on range sites in winter. Seeds and caryopses of alien weeds and exotic wheatgrasses were recovered more frequently from the pouches of rodents than seeds of native species.
    • Sheep Behavior Under Unherded Conditions on Mountain Summer Ranges

      Bowns, J. E. (Society for Range Management, 1971-03-01)
      Purebred Rambouillet, Targhee and Columbia sheep were observed on mountain summer ranges in southwestern Utah. Under unherded conditions Rambouillet sheep travelled greater distances and spent more time resting, while Columbias travelled the least distances, rested least and grazed longer than the other breeds. All breeds travelled farther in the morning than in the afternoon but grazed longer in the afternoon. There was a tendency for the sheep to water and take salt in the mornings rather than in the afternoons. Overgrazing on established bedgrounds was caused by animals grazing these areas in the evening prior to bedding down. Fencing along the crests of the ridges and more strategic salt placement appear to be the most useful means of improving distribution.