• Ranching in Panama

      McCorkle, J. S. (Society for Range Management, 1968-07-01)
      Grass and cattle are an important part of Panama agriculture. Ninety percent of all grassland contains one or more introduced grasses. Brush control, fire control, and improvement in grass and livestock management are major problems. Cattle are grown and finished for market on grass. Low calf crops, disease and parasites, poor dry season feed conditions, and low-quality animals result in a generally low beef production per cow. Improved grazing practices and sound livestock management will result in higher calf crops and increased beef yields. Potential exists for a sound and economically profitable ranching enterprise./Los pastizales y el ganado son una parte muy importante de la agricultura de Panamá. El 90% de las tierras de pastoreo contienen una ó más especies de gramíneas introducidas. El combate de arbustivas, el control de las quemas, y el mejoramiento tanto de las plantas forrajeras como del ganado son de los problemas más importantes. El ganado se cría y se engorda para el mercado en los potreros. Los bajos porcentajes de parición, las enfermedades y los parásitos, el bajo valor nutritivo de los forrajes durante las épocas de sequía, y los animales de calidad inferior traen como consecuencia, por lo general, una baja producción por vaca. Mayores porcentajes de parición y aumentos en el rendimiento de carne podrán lograrse mediante prácticas de pastoreo mejoradas y un manejo adecuado del ganado. La ganadería en Panamá ofrece un buen potencial para establecer empresas remunerativas.
    • Preplanting Treatment to Hasten Germination and Emergence of Grass Seed

      Keller, W.; Bleak, A. T. (Society for Range Management, 1968-07-01)
      Seeds in the crested wheatgrass complex were placed under conditions favorable for germination for periods of 10 to 90 hr, superficially dried, and then planted on a greenhouse bench. The most effective treatment was at 63 F for 60 to 70 hr. Seedlings resulting from this treatment emerged about 40 hr ahead of untreated seeds. The study suggests that if field tests yield similar results, pretreatment of seed may contribute towards greater success in range seeding.
    • Rates of Seeding Rambler Alfalfa with Dryland Pasture Grasses

      Kilcher, M. R.; Heinrichs, D. H. (Society for Range Management, 1968-07-01)
      Rambler alfalfa, crested wheatgrass, and Russian wild ryegrass were combined to give five rates of seeding. These rates were achieved by mixing 0.25, 0.5, 1.0, 1.5, and 2.0 lb of the alfalfa with 3 lb of seed of each grass and seeding the mixtures at these rates per acre. In four of the seven harvest years the mixture seeded at 1 lb/acre of alfalfa significantly outyielded those seeded at 0.25 and 0.5 lb/acre, however, there was no difference in yield between the three highest rates of seeding treatments. Increasing the seeding rate of alfalfa resulted in increased plant density of the mixture by increasing the alfalfa component while not affecting the density of the grass component. It was concluded that the creeping-rooted Rambler alfalfa need not be seeded at a rate exceeding 1.0 lb/acre when grown in combination with grass for dryland forage production.
    • Tolerance of Subclover, Rose clover, Hardinggrass, and Orchardgrass to 2,4-D

      Kay, B. L. (Society for Range Management, 1968-07-01)
      Species commonly used to seed California rangelands were sprayed with varying rates of the alkanolamine salt of 2,4-D at a number of vegetative growth stages in two different years. Subclover, hardinggrass, and orchardgrass were not permanently damaged by rates up to 2.0 lb/acre at any of the growth stages tested. Rose clover was tolerant of up to 0.5 lb/acre if sprayed at the proper growth stage but yields were frequently reduced by even low rates at other growth stages.
    • Growth and Yield of Legumes in Mixtures with Grasses on a Mountain Range

      Bleak, A. T. (Society for Range Management, 1968-07-01)
      Nine legumes, including three strains of variegated alfalfa, were planted in mixture with each of four grasses in the fall of 1950. Alfalfa A-169 was the most productive legume. In 1965 it yielded 100 lb/acre, about 35% more than cicer milkvetch or Ladak alfalfa and 160 lb/acre more than sickle milkvetch or Rhizoma alfalfa. Siberian alfalfa was clearly inferior to all the above. Flat pea, birdsfoot trefoil, and perennial vetch disappeared from the plots early in the study. Intermediate and crested wheatgrasses were more productive than smooth brome, both in combination with legumes and as pure stands. The highest yielding plots in 1965 were those originally sown to mountain brome. This short-lived grass afforded less competition to the legumes which became well established prior to invasion by crested and intermediate wheatgrass or smooth brome grass. The use of a legume with the grass, on the average, increased production by 144 lb/acre.
    • Estimating Percentage Dry Weight in Diets Using a Microscopic Technique

      Sparks, Donnie R.; Malechek, John C. (Society for Range Management, 1968-07-01)
      Percent composition by dry weight was accurately estimated for 15 mixtures of plants that are found in the diets of some herbivores. The mixtures were sampled by recording the frequency of occurrence of each species in 100 microscope fields using 125-power magnification, converting frequency to density, and calculating relative density as an estimate of percent composition by dry weight. Dry weight percentages were predicted directly from relative density. The microscopic technique reported in this paper would be an accurate means of determining the dry-weight composition of stomach samples, esophageal samples, rumen samples, and clipped herbage.
    • Forage Ratings for Deer and Cattle on the Welder Wildlife Refuge

      Drawe, D. L.; Box, T. W. (Society for Range Management, 1968-07-01)
      Forage preferences of white-tailed deer and cattle on the Welder Wildlife Refuge in South Texas were determined by relating availability, percent utilization, and percent frequency of use of each plant species utilized by deer or cattle. Overall forage ratings showed that though both animals were grazers, deer preferred forbs and cattle preferred grasses. Selection of forage by both deer and cattle varied with the seasonal availability and palatability of the forage. Seasonal forage ratings showed that few species of the many utilized made up 50% of the forage ratings for deer and cattle. On clay soils, deer utilized all browse species present, while cattle utilized little browse. Four perennial grasses made up most of the preferences of cattle. During the winter, grass and grass seed heads were highly utilized by deer. Forbs were the most important deer forage class on sandy soils. Grasses made up about 25% of the total preference rating of deer in fall and winter on the sand. Cattle utilized forbs more in spring and summer, but utilized grasses more in the fall and winter.
    • Forage Moisture Variations on Mountain Summer Range

      Sharif, C. M.; West, N. E. (Society for Range Management, 1968-07-01)
      Diurnal and seasonal differences, as well as site features of slope aspect and shading, were found to be significant variables related to forage moisture content on a mountain summer range in northern Utah. These variations, if ignored in range analysis, can have considerable practical consequence. Therefore, improvements on wet to dry-weight conversion factors have been suggested.
    • Juniper Extract and Germination of Six Range Species

      Lavin, Fred; Jameson, Donald A.; Gomm, F. B. (Society for Range Management, 1968-07-01)
      Juniper foliage extract significantly decreased seed germination for three of six range species tested. Deficient aeration severely decreased germination for two species and completely inhibited germination of the other four.
    • Maturity Studies with Western Wheatgrass

      Kamstra, L. D.; Schentzel, D. L.; Lewis, J. K.; Elderkin, R. L. (Society for Range Management, 1968-07-01)
      Leaf class (number of leaves per plant) and cutting date were considered as indices of maturity of western wheatgrass. Although some early-season effects of leaf class could be demonstrated, cutting date was a better measure of stage of maturity. Cutting date but not leaf class was shown to affect plant fractions and chemical components. The upper portion of the plant was more digestible than the basal portion. No digestibility effect was demonstrated for topographic location or leaf class. Leaf blades removed from plants under heavy grazing were more digestible in vitro than those from lightly-grazed pastures, probably because of later emergence or shorter height.
    • Adjusting Cattle Numbers to Fluctuating Forage Production with Statistical Decision Theory

      Rogers, L. F.; Peacock, W. S. (Society for Range Management, 1968-07-01)
      Statistical decision theory offers northern Nevada cattle producers an opportunity to increase their income by aiding in making adjustments in livestock numbers according to expected forage production. It is necessary for cattlemen to determine the number of cattle to carry through the winter before knowledge of forage supply for the coming year is available. Statistical decision theory provides a simple tool whereby ranchers may use observed information on precipitation to select the appropriate number of cattle to be wintered. Ninety-five years of weather data were used to evaluate this technique under ranch conditions in northern Nevada. Results indicate that statistical decision theory offers promise as a technique for maximizing the long-run average income of ranchers while making provision for protection of the range resource./Para ejemplificar este modelo bajo probabilidades a priori y a posteriori, se empleó una operación combinada de pié de cría (venta de crías al destete) y de pié de cría-engorda (venta de crías como añojos). Esta organización tiene muy buena flexibilidad para ajustarse a niveles de producción forrajera tanto abajo como arriba de lo normal. Por lo tanto, el valor del modelo expuesto fué más bien limitado para este sistema. El modelo resultó de mayor valor bajo el sistema menos flexible de una operación pié de cría. Aunque los aumentos en los ingresos fueron modestos con el modelo, la técnica ofrece ciertas promesas para trabajar en este campo. La técnica puede aparecer complicada al principio, pero es más bien simple. Los resultados pueden presentarse en una forma sencilla, como aparecen en el cuadro 6, para aquellos no interesados en profundizarse en suposiciones y mayores datos. Este modelo fué desarrollado para ayudar a los ganaderos a utilizar los reducidos datos disponibles en el otoño con el fin de predecir la cantidad de forraje disponible para el año siguiente. El modelo está planeado simplemente para tratar de obtener los máximos ingresos a largo plazo. Podría modificarse fácilmente para reflejar otras cosas tales como diferentes grados de utilización de forraje aceptable, niveles de ingreso mímimo anual, ó cualquier otra medida de importancia en el manejo del recurso pastizal. Esta es otra herramienta que puede ayudar al ganadero a aumentar sus ingresos y a la vez sirve para mejorar la utilización de un pastizal.
    • Apparent Sap Velocities in Big Sagebrush

      Gifford, Gerald F. (Society for Range Management, 1968-07-01)
      Peak daily sap velocities were rather consistent throughout the year, and were always less than five cm/hr (average of five plants). A 30-variable multiple regression equation involving environmental parameters measured near plants accounted for only 54.05% of variability associated with apparent sap velocity measurements. Big sagebrush plants must, therefore, exert considerable physiological control of transpirational water losses.
    • Carbohydrate Reserves of Sand Reedgrass under Different Grazing Intensities

      Welch, T. G. (Society for Range Management, 1968-07-01)
      Stored carbohydrates of sand reedgrass increased from a low in late May and early June to a maximum in late September and early October. Starch was the major stored carbohydrate. The concentration of starch in the roots decreased slightly with increased grazing intensity. The results of this study combined with information on the morphological development, extent of root system, and other physiological aspects of sand reedgrass can be used in developing grazing management systems for sand reedgrass.
    • Recreation and Range Use

      Wolstad, G. R. (Society for Range Management, 1968-07-01)
    • Sagebrush Reinvasion as Affected by some Environmental Influences

      Johnson, J. R.; Payne, G. F. (Society for Range Management, 1968-07-01)
      Five chemically sprayed and 15 plowed and seeded areas in southwestern Montana were examined to determine the influence of several environmental factors on big sagebrush reinvasion. Sagebrush surviving the treatments was found to be the most important factor related to reinvasion. Plowing near or after sagebrush seed maturation resulted in heavy reinfestation of seeded stands. Sagebrush adjacent to treated areas was of no practical importance as a seed source for reinvasion. Non-sagebrush vegetation, slope, erosion, soil texture, and precipitation were seldom related to sagebrush reinvasion. Northwest exposures favored reinvasion.
    • Seasonal Grazing of Crested Wheatgrass by Cattle

      Harris, L. E.; Frischknecht, N. C.; Sudweeks, E. M. (Society for Range Management, 1968-07-01)
      Thirty-six pastures of crested wheatgrass were grazed in early spring plus early fall; late spring; all spring; early summer; late summer; early fall; and late fall. Summer and fall treatments included grazing with and without supplement. Yearlings made substantial gains in all seasons except during late fall when they lost weight. They finished the entire grazing period with an average gain of 224 lb. Calves gained 249 lb. Yearlings and calves did as well on crested wheatgrass as on forest range, and supplementation provided no additional gain. Cows on supplement gained 125 lb as compared to 50 lb for non-supplemented cows. In years with no fall regrowth, second grazing of crested wheatgrass without supplement produced daily gains in early fall equal to those for single grazing with supplement.
    • The Effects of Fire on Seed Germination

      Cushwa, C. T.; Martin, R. E.; Miller, R. L. (Society for Range Management, 1968-07-01)
      Fire is characteristically used in the pineywoods of the Southeast to produce repetitive abundant stands of native legumes. However, results are frequently erratic and unpredictable. Seed germination results following simulated fire conditions are presented. Results show dry heat ineffective in increasing germination, whereas moist heat greatly increased both germination rate and total germination of some species of seed.
    • Diet of Black-Tailed Jackrabbits on Sandhill Rangeland in Colorado

      Sparks, D. R. (Society for Range Management, 1968-07-01)
      The diet and forage preferences of the black-tailed jackrabbit (Lepus californicus) were studied by stomach content analysis to determine the degree of competition between cattle and jackrabbits on sandhill rangeland. Grasses were most important in the diet in early spring and summer. Forbs were important during summer and fall and shrubs were eaten in fall and winter. Competition for forage between jackrabbits and cattle was greatest in early spring and least in late fall and winter. Jackrabbits influence the longevity of reseeded forage stands and the secondary succession on old fields. A thorough knowledge of diet and forage preferences of jackrabbits permits the land manager to make better decisions for efficient range use.
    • Demarcation of Small Plots with Spring-Loaded Wires

      Duvall, V. L. (Society for Range Management, 1968-07-01)
      Wires have some advantages over frames for delineating plot boundaries.