Location: Forage and Livestock Production Research2010 Annual Report
1a. Objectives (from AD-416)
The primary goal is to develop a knowledge base and guidelines that will enable producers in the southern Great Plains to diversify forage-based systems, to enhance flexibility and efficiency, and to reduce economic and environmental risks under variable climate, market and policy conditions. The approach is to develop sustainable systems that integrate a diversity of plant species including forages for livestock, multi-purpose crops, and biomass production. Specific objectives include: Objective 1: Provide perennial grasses to regional livestock producers that are adapted, productive, persistent, exhibit desired agronomic characteristics, and can be included in year-round forage based production systems. • Sub-objective 1.A. Develop and evaluate germplasm resources of perennial cool-season grass forages that exhibit favorable agronomic characteristics and are adapted to the climate of the southern Great Plains. • Sub-objective 1.B. Develop PCR-based molecular markers to assist perennial cool-season grass breeding, with emphasis on bluegrasses. • Sub-objective 1.C. Evaluate smooth bromegrass, wheatgrasses, and tall fescues under intensive, short-duration grazing during spring and fall in near year-long forage production systems. Objective 2: Evaluate quality and anti-quality factors in existing forage based livestock production systems that limit animal performance. • Sub-objective 2.A. Evaluate adapted winter wheat cultivars and breeding lines for variation in concentrations of secondary metabolites that may limit the incidence of frothy bloat, and for accumulation of nitrate that may limit performance of cattle grazing wheat forage. • Sub-objective 2.B. Provide a real-time, remote-sensing based approach for estimating forage quality in the field. Objective 3: Incorporate multipurpose legume and grass forage, grain, and biomass crops into integrated and diversified systems that provide a range of agricultural opportunities. • Sub-objective 3.A. Assess the feasibility of integrating multipurpose forage and grain crops into diversified forage and livestock production systems. • Sub-objective 3.B. Provide the knowledge and guidelines required to integrate biomass/bioenergy crops into agricultural land management systems of the southern Great Plains. • Sub-objective 3.C. Assess amounts of nitrogen contributed to subsequent forage, grain and biomass crops by annual and perennial legumes. Objective 4: Provide the knowledge and guidelines required to implement and manage year-long forage based livestock production systems. • Sub-objective 4.A. Design, install, and evaluate farm-scale, year-long forage production systems that include multiple forage species to fill gaps in spring and fall when high-quality forage is not available. • Sub-objective 4.B. Determine whether fast-growing annual legumes and grasses have potential as gap-filling forages for use in near year-long forage production systems in the southern Great Plains.
1b. Approach (from AD-416)
Germplasm with potential for use in the region will be obtained from a variety of sources and evaluated in the field for adaptation, productivity, forage quality, and other traits. Persistence, productivity, and quality of selected perennial cool-season grasses will be genetically improved through traditional and marker assisted breeding methods and interspecific hybridization. Forage crop sequences, including grass, legumes, and legume/grass mixtures will be evaluated in the field under varying levels of fertilization, grazing pressure, and abiotic stress. Hyperspectral reflectance data will be compared to laboratory analyses and bench top near-infrared spectroscopy as an approach to monitoring in-field forage quality and biomass production. Productive and adapted bioenergy feedstock crops will be identified and efficient feedstock production systems developed. Approaches to incorporate feedstock production into existing forage and livestock production systems will be investigated. All proposed research will be in collaboration with ARS, university and private cooperators where appropriate and mutually beneficial.
3. Progress Report
Smooth bromegrass and fescue materials were transferred via a materials transfer agreement (MTA) and the cooperative research development agreement (CRADA 58-3K95-8-1233) for multi-location performance trials was continued. An invention disclosure related to the development of Lolium spp. was submitted to the USDA-OTT, and a U.S. patent application was entered on Sept. 23, 2009. One 'creeping wheatgrass selection' remains under evaluation for commercial seed production. Performance trials of orchardgrass varieties Nakei 26 and Nakei 27 and a 'stress tolerant' orchardgrass were initiated. Approximately 380 Poa molecular markers were generated and evaluated against eight Poa species and their interspecific hybrids. The markers were used to identify a development process in P. arachnifera (Texas bluegrass) that can enhance the efficiency of breeding of Poa lines that have the ability to reproduce asexually through seed, producing plants identical to the maternal plant. Scientists at El Reno, in cooperation with scientists from the Noble Foundation, Ardmore, OK, found that short-term periods (30 to 35 days) of intensive grazing on pastures of non-toxic endophyte-infected tall fescues produced stocker cattle gains of 1.7 to 2 lb per day in October and 2 to 2.5 lb per day in May. Tall wheatgrass pastures produced similar responses. Expansion of tannin research led to development of a project funded by the Animal Compassion Foundation associated with Whole Foods Market and an in-house project evaluating the usefulness of tannins in Ozark Plateau forbs and in peanut skins as worming agents for sheep and goats. The use of grains to produce ethanol is increasing the costs of cattle gains in feedlots, resulting in greater demand for larger feeder cattle. Many producers are unwilling to convert cropland to permanent pasture, but would like to hold stocker cattle for longer periods than wheat pasture can support. Results from pastures of non-toxic endophyte-infected tall fescues and wheatgrass, wheat, mixtures of annual grasses and legumes, and perennial warm-season grasses indicate that stocker cattle can gain 500 to 600 lb on forages. Evaluations of combinations of annuals, including grasses and legumes, as an alternative to perennial forage pastures are ongoing. Cool-season mixes of annual rye, wheat, and annual ryegrass, with and without red clover, have provided forage to allow grazing by stocker cattle during November through May, and supported average daily gains of 1.7 to 2.5 lb per day. Warm-season mixes of sorghum-sudangrass with and without lablab, or soybean provided high-quality forage during July through August, and supported similar weight gains. Redcedar (Juniperus virginiana L.), is an invasive species that seriously degrades prairie grasslands and adjacent landscapes in the southern Great Plains. Ongoing research has determined that a large redcedar biofuel feedstock exists and a range of 14 to 40 t ha-1 of dry feedstock on invested land is available. Satellite imagery is being utilized to accurately locate and quantify this resource.
1. An efficient method for measuring nonstructural carbohydrate components in forages. Plants use nonstructural carbohydrates, products of photosynthesis, as a form of energy currency to drive respiration and synthesis of other compounds that support the fitness and growth of plants. This class of carbohydrates also is a readily used energy source of forages consumed by livestock and of plant products consumed by humans. Determination of nonstructural carbohydrate composition and concentrations is often necessary for estimating the resources that are available for plant growth and for evaluating forage energy value to grazing animals. A new commercially available glucose reagent kit (GAHK-20) from Sigma Chemical Co. was adapted for a 96-well microplate format that permits scaled down chemical reactions and assays to be performed. The accuracy of this adapted reaction format was tested for quantifying nonstructural carbohydrate concentrations in 11 cool-season perennial grass species. The microplate method produced precise, accurate, and reliable assays of nonstructural carbohydrate components (i.e., glucose, fructose, sucrose, fructan, and starch) and their concentrations in grass forages. The format of this method is especially useful for a large number of samples. With the microplate format, less enzyme reagents can be used for the ethanol extracts of plant samples and many samples can be assayed each time, thereby improving use of reagents and measurement efficiency, making the assays very cost effective. This microplate assay method should be suitable for measuring nonstructural carbohydrate concentrations in fresh or dry tissues of a variety of other plant samples in addition to forage grasses and is expected to be valuable to nutritionists needing to evaluate the quality of forages for livestock and plant products intended for human consumption.
2. Can genotype variation in crude protein and initial in vitro dry matter digestibility of wheat forage be exploited to reduce frequency and severity of bloat? Even though winter wheat pasture in the southern Great Plains is considered excellent forage, devastating losses of stocker cattle can occur due to pasture bloat. Average death losses of stocker cattle due to bloat costs producers in the southern Great Plains as much as $100 million each year. The development of wheat varieties that decrease losses of average daily weight gain to non-lethal bloat episodes, death losses due to bloat, and the cost and uncertainties of active bloat intervention strategies would be useful to cattle producers in the southern Great Plains that rely so heavily on wheat for their cool-season forage base. Elevated levels of forage crude protein (CP) and a rapid rate of forage digestibility contribute to pasture bloat. We examined adapted wheat varieties that are commonly grazed and a set of 221 diverse breeding lines to characterize the variation in CP and digestibility that might be exploited through wheat breeding to deliver wheat that could offer a decreased frequency and severity of bloat. Substantial differences in the CP concentration and rate of digestibility were observed among adapted varieties and breeding lines. This variation may be useful to breeders wishing to develop lines intended for grazing by stocker cattle. The CP and digestibility traits, however, were poorly correlated, indicating that it will be necessary to select for both traits simultaneously if one seeks to reduce both CP concentration and forage digestibility. These results will be useful to wheat breeders seeking to develop varieties better suited for use in the southern Great Plains.
5. Significant Activities that Support Special Target Populations
Research under this project is conducted in close collaboration with the staff of Langston University, a 1890s university located at Langston, OK, and the scientists of the Grazinglands Research Laboratory who are permanently stationed at Langston University (project 6218-12210-003-00D). That research project addresses the unique problems encountered by small, minority, and socially disadvantaged/limited resource forage and livestock producers. During the fiscal year, scientists stationed at El Reno worked closely with faculty and students at Langston University to provide training, grant-writing assistance, and research experiences.