Location: Forage and Range Research
Project Number: 2080-21000-014-33-S
Project Type: Specific Cooperative Agreement
Start Date: Jul 16, 2014
End Date: Jul 15, 2019
The objectives of this cooperative research project are: 1) Evaluate cow-calf performance when grazing mixtures of pasture grasses and legumes; 2) Evaluate the nutritive content of grass and legume mixtures; and 3) Breed grasses and legumes with enhanced compatibility in mixtures and improved persistance under both biotic (grazing) and abiotic (climate) stress.
This research is an expansion and continuation of the research goals and objectives originally started under SCA #58-5428-9-311 entitled "Develop and evaluate grass and legume mixtures for improved livestock performance." That research determined that tall fescue grown with birdsfoot trefoil, a tannin containing legume, improved steer weights and reduced methane production. However, critical questions remain, including: (1) which grass-legume mixtures can provide both high tannin and energy levels, and (2) how will these grass-legume mixtures directly affect cow-calf productivity? This research proposes to evaluate these quesitons. Birdsfoot trefoil (tannin source) will be grown in mixtures with grasses that inherently vary in energy and ability to capture nitrogen in replicated large pastures. Cow-calf pairs will be allowed to graze treatments throughout the summer, and milk content and production, calf weight, ruminal ammonia production, and forage quantity and nutritive value will be determined. In-vitro and small-plot studies will further evaluate tannins and forage nutritive energy using various grass-legume combinations and continuous culture to elucidate ruminal microbial ecology and physiology. In addition, the phenotypic and genotypic variation within various grasses and legumes will be evaluated for persistence when grown under abiotic (temperature, drought, etc) and biotic (grazing) stresses.