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Research Project: Use of Animal Genetics and Diversified Forage Systems to Improve Efficiency and Sustainability of Livestock Production Systems in the Southern Great Plains

Location: Forage and Livestock Production Research

2021 Annual Report

The long-term objective is to improve understanding of forage-based production systems and genetics that allow ruminant livestock to efficiently consume and convert feedstuffs, primarily forages. Specifically, during the next five years we will focus on the following objectives. Objective 1: Evaluate nutrient-use and production efficiency in reproductive and terminal beef cattle within conventional and unconventional production systems in the Southern Great Plains (SGP). • Sub-objective 1A: Determine the relationship between frame score and calf growth rate, carcass quality, and economic returns under different finishing systems. • Sub-objective 1B: Evaluate traditional and novel annual grain crops for their efficacy as forages within beef production systems used in the SGP. • Sub-objective 1C: Determine the relationship between Residual Feed Intake (RFI) evaluations conducted in growing heifers and those conducted again in the same animals as mature cows within the SGP. • Sub-objective 1D: Characterize rumen metagenome and metabolome in relation to animal nutrient-use/production efficiency in beef cattle consuming forage and forage-grain diets. Objective 2: Determine the impact of management and animal genetics on health and stress related indices, and beef quality. • Sub-objective 2A: Determine the impact of finishing system (pasture versus confinement) on animal stress level indicators, and end product. • Sub-objective 2B: Evaluate the impact of cow management system on temperament and productivity in range cows and their offspring. Objective 3: Determine relationships between genetic/genomic characterizations in beef cattle and: a) the environmental and managerial responses, and b) the production phases. • Sub-objective 3A: Characterize environmental, managerial, and sire impacts on production responses within contemporary groups of cattle. • Sub-objective 3B: Evaluate the relationships between genetic markers of the rumen biome and key responses during the production phases.

Over the last 50 years, annual U.S. beef production has increased with fewer cows in the national herd by harvesting larger animals. This is due in part to availability and use of low-priced, abundant feed grains. While feed costs represent the single largest expense in beef production, less than 20% of the post-weaning feed energy consumed is converted to edible product. As competition and the price of feed grains increases due to growing global human population, use of grains for energy production, and other uses, beef production enterprises may need to transition from greater grain dependency to greater reliance on forage resources (pasture and rangeland) produced on lands not suitable for more intensive crop production. We propose to improve the efficiencies and sustainability of conventional forage-based components of beef production systems by development of more efficient management systems. In addition, identification of animal genetics best adapted to forage-based production systems in the Southern Great Plains (SGP) will aid in understanding how to reduce animal stress in management systems. The end result will be improved efficiencies of beef production with less grain and fossil fuel inputs, less need for capital through increased use of on-farm products, and increased competitiveness and profitability for producers. To accomplish this goal, the interactions of animal genetics, nutrient-use, health, and the beef system components must be understood to best match the animal resource with the forage resource. There is also a need to understand some of the ecological benefits and impacts of forage-based components of forage-based beef production systems.

Progress Report
(Objective 1, Sub-objective 1A) Evaluation of finishing system using forages continued, although all animals will be finished on pasture; the feedlot component will not be conducted due to high corn and commodity prices for the rations needed and the uncertainty of packer availability to collect carcass data. (Objective 1, Sub-objective 1B) Ancillary research focusing on different remote sensing techniques for nitrogen (and crude protein) in novel forages, and another on modelling to identify management for optimal production of forage soybean and winter wheat in intensive, double-cropped rotations under the sub-objectives are ahead of schedule. (Objective 1, Sub-objective 1C) A third year evaluating cow residual feed intake (RFI) was initiated. (Objective 1, Sub-objective 1 D) A third year evaluating the rumen microbiome of the RFI cows was initiated. Under an agreement with researchers at Texas A&M AgriLife Research at Vernon, Texas, a grazing project was completed to monitor changes in rumen microbiome ecology during the growing season as steers grazed a native warm-season grass pasture that was controlled burned in the spring. Samples are currently under analyses at Texas A&M University. (Objective 2, Sub-objective 2A) Research continued to monitor beef animal stress (cortisol) during growing and finishing phases. (Objective 2, Sub-objective 2B) Cow management on temperament and productivity has been completed. (Objective 3, Sub-objective 3A and 3B) A Beef Grand Challenge collaborative research plan with ARS researchers at Clay Center, Nebraska, and Miles City, Montana, continued for the third year with performance data collected. Blood samples and rumen samples for rumen microbiome linkages were collected during the early stockering phase on winter wheat pasture; during the late stockering phase on winter wheat pasture; and the finishing phase on a feedlot ration. This project integrates novel genomic approaches to enhance knowledge of the bovine genome, improve genetic merit of purebred and crossbred beef cattle, and improve beef cow energetic efficiency, especially related to grazing and high forage-based diets in order to evaluate genetics x management x production environment interactions.

1. Introducing grazable cover crops into winter wheat production systems. An ARS researcher at El Reno, Oklahoma, along with collaborators evaluated grazable cover crops in winter wheat cropping systems in Oklahoma. Winter wheat is the primary cash crop in Oklahoma with regards to acres and economic importance. In most production systems, fields are typically kept fallow during summer after winter wheat grain harvest in the U.S. Southern Great Plains (SGP). Introducing summer cover crops to the system could increase soil conservation and farm profitability if grazed. This study evaluated some commonly cultivated warm-season legumes and grasses and their mixtures as summer cover crops with canopies harvested at different cutting (stubble) heights. Initial results showed that a warm-season grass (sorghum-sudangrass hybrid) and all grass-legume mixtures produced the greatest available forage dry matter during summer for grazing. Warm-season grasses and grass-legume mixtures had greater forage dry matter residue and provided greater weed suppression than legumes alone. Overall, findings suggest that nitrogen uptake by high-biomass grasses and mixtures might result in deficient water and nitrogen availability for the next season’s wheat production. Developing improved guidelines based on decision-supporting tools would allow flexible rotations based on current weather forecasting and aid in the implementation of feasible grazing cover crop-winter wheat systems in the SGP.

Review Publications
Baath, G.S., Northup, B.K., Rao, S.C., Kakani, V.G. 2021. Productivity and water use in intensified forage soybean-wheat cropping systems of the US Southern Great Plains. Field Crops Research. 265:108086.
Niraula, R., Saleh, A., Bhattarai, N., Kannan, N., Osei, E., Gowda, P.H., Neel, J.P., Xiao, X., Basara, J. 2019. Understanding the effects of pasture type and stocking rate on the hydrology of the Southern Great Plains. Science of the Total Environment. 708:134873.
Horn, K.M., Rocateli, A.C., Warren, J.G., Turner, K.E., Antonangelo, J.A. 2020. Introducing grazeable cover crops to the winter wheat systems in Oklahoma. Agronomy Journal. 112:3677-3694.