The Energy Expenditure of Heifers Grazing Crested Wheatgrass Rangeland in West-Central Utah

The free-roaming ruminant requires energy for the demands of vii grazing, traveling and thermoregulation that are not required by its confined counterpart. Literature estimates of these additional costs range from 10 to 170 percent above maintenance. The uncertain magnitude of this increased demand and the factors that contribute to it impede the ability of the rangeland ruminant nutritionist to establish guidelines for the energy requirements of the free-roaming herbivore. This study was designed to estimate the energy expenditure of yearling Angus heifers while grazing a declining supply of available crested wheatgrass forage (Agropyron cristatum) on rangeland in west-central Utah. Free-ranging energy expenditure was estimated twice for four heifers during each of five ten-day periods during June, July August and early September, 1979. These estimates were obtained using the carbon dioxide entry rate technique. In addition, total fecal output, dietary crude protein and dietary in vitro organic matter digestibility were estimated for animals grazing the 20- hectare crested wheatgrass pasture. From these data, daily forage intake was calculated. The level of available forage during each period was estimated using the ocular weight-estimate technique applied on forty 1 m2 circular plots. Energy expenditure was estimated as 161 (with a confidence interval of ±43) kcal·kg body weight-.75.d-1 (n=10), and was independent of the decline in available forage from 880 to 284 kg dry matter·hectare-1 that occurred over the course of the grazing season. Daily intake was 54.5 grams (organic matter basis) per unit body weight.75 for the 305 kg heifers. Daily intake was independent of the supply of available forage. During early July, 1980, crested wheatgrass was harvested as hay and fed to 260 kg yearling Angus heifers in metabolism stalls in a thermoneutral and constantly illuminated laboratory. Daily feeding levels were set at 54.5 grams (organic matter basis) per unit body weight.75. Energy expenditure under these conditions was estimated as 111 (±12) kcal·kg body weight-.75·day-1 , 6 kcal per unit body weight.75 greater than the mean estimate of the fasting metabolism rate. The latter estimate was obtained following a 48-hour fast. These estimates of maintenance and fasting metabolism were combined to provide a mean estimate of 110 (±10) kcal·kg body weight-.75·day-1 (n=14). Of the 45 percent (51 kcal·kg body weight-.75·day-1) increase in the estimated energy expenditures by heifers under free-roaming conditions, 50 percent was attributed to the energetic cost of grazing. A daily average 9.2 hours were spent in this activity. The energetic cost of grazing was assumed as 0.82 kcal·kg body weight-1·hour-1 spent grazing. Daily travel was estimated as 3.9 km at an assumed energetic cost of 0.58 kcal·kg body weight-1·km-1. This accounted for a 20 percent estimated increase in energy expenditure. Average daily temperatures were generally between 12°C and 30°C and thermoregulatory demands were not considered as a substantial energetic expense. The remaining 30 percent (12 kcal) of the additional increment due to free-roaming conditions could not be explained

Toward a Method of Collaborative, Evidence-Based Response to Desertification

Over generalized narratives about how desertified ecosystems will respond to restoration actions may result in wasted resources, missed opportunities, or accelerated degradation. Evidence-based collaborative adaptive management (CAM) could solve this problem by providing site-specific information that is trusted by users and enables learning opportunities. Although calls for CAM are increasing, many recommendations remain abstract and difficult to operationalize in specific projects. We review some general challenges for managing desertification in rangelands and draw upon recommendations in the recent literature to develop a 6-step method of CAM to address desertification. The method draws upon our ongoing experiences and makes novel connections between CAM concepts and technologies including ecological sites, state-and-transition models, ecological state mapping, and web-based knowledge systems. The development of a broadly-applicable and flexible methodology for CAM could increase the frequency and success of projects and provide sorely needed knowledge to guide locally-tailored responses to desertification

Grassland Rehabilitation through Re-Designing Livestock Management Systems

Grasslands are one of the most important land types supplying critical ecosystem services including feed for livestock grazing. They occupy ~54% of the world’s ice-free land surface. China contains the third largest area of grassland in the world, ~400 M ha, ~40% of China’s land surface. Chinese grasslands are severely degraded primarily due to overgrazing, which contributes to local poverty because of poor livestock production. To both recover the degraded grassland and to enhance the local herders’ income, a large farm-scale experiment was conducted in a desert steppe of Inner Mongolia, China from 2007 to 2012. We used a baseline survey, production models, and extension with government and private companies to test a redesigned grassland livestock management system. The new system employed summer grazing, winter greenhouse shed feeding, a reduction of overall stocking rate, lambing in summer (July), livestock infrastructure structure improvements, use of animal nutrient supplements, and incorporating crossbred Dorper and Mongolian sheep. This system showed positive advantages on animal production and household net income and transformed livestock production from a survival to a production enterprise. Of critical additional importance was that grassland rehabilitation occurred with the new management system, albeit slower than the more immediate positive changes to animal performance and herder net incomes. The integration of science, government and industry were key for this successful large-scale farm experiment

Tactical Themes for Rangeland Research

The problems threatening the conservation and management of rangeland, over one-half of the world’s terrestrial surfaces, are significant and growing. Current assessments of drivers and externalities shaping these problems have resulted in strategies intended to result in sustainable development of these lands and their resources. However, how can individual scientists and individual research programs support the needed strategies and goals? What can we realistically contribute and accomplish? We believe that technology can connect individual scientists and their science to the problems manifest in rangelands over the world, in a more rapid exchange than has occurred in the past. Recognition of local challenges, innovations, and scientific tests of the effectiveness of our technological solutions to these problems can keep pace with rapid change and help us adapt to that change. However, to do this, we have to invest in a process of connecting science to landscapes. Our tactics are to link, openly and collaboratively, the scientific method to discrete, specific, managed landscapes. We term these collective tactics, our fundamental research theme, “Landscape Portals”. All of the elements of this theme exist currently, to various degrees, but they lack cohesion and interactive, real-time connections. Future investment requires two basic, tactical scientific behaviors: a post-normal application of science in support of land management by hypothesis and a scientific method modified to accommodate a data intensive scientific inquiry directed towards adaptive management. These behaviors support our “Landscape Portals” theme: science conducted in a highly interactive, transparent, data enriched, locally relevant, globally connected, popularly translated, and ecologically robust manner

Using Ecological Site Information to Improve Landscape Management for Ecosystem Services

On the Ground • Ecological sites and their component state-and-transition models are valuable tools for predicting the effects of climatic and management changes on a variety of ecosystem services. • Site-specific information must be able to be both refined to finer scales to account for spatiotemporal variability within a mapped site and expanded to include interactions with other sites in the landscape to identify priorities and account for integrative disturbances and ecosystem services such as wildlife habitat, hydrology, fire, insect outbreak and invasive species. • Ecological site groups, spatially contiguous and behaviorally similar, are an important level in the land hierarchy to organize and interpret information.The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform March 202