Grass-legume mixtures for improved persistence, biomass production, and intake by dairy cattle on pasture

Grass-legume mixtures for improved persistence, biomass production, and intake by dairy cattle on pasture

Summary

A major biological limitation to profitability of grazing dairy operations is low forage intake by grazing cows relative to that obtained in confinement operations. This is related to pasture sward density, seasonal yield distribution and growth rate—all functions of plant species in the pasture as well as management and environmental conditions affecting plant growth. Our environment may require several types of pasture to optimize full season production—we don’t know. Genetic advances have been made in both pasture grasses and legumes that should allow development of mixtures that are capable of supporting greater levels of livestock performance than currently achieved by graziers. We propose to measure growth rate, sward density, feeding value (with laboratory assays) and yield and proportions of grass and legume in swards defoliated at 28 to 35 day intervals. A total of 21 different combinations of new and traditional grass and legume species/varieties will be evaluated on two university research stations in WI and MN. Improving pasture performance, and thereby profitability of dairy farmers, will improve the quality of life of dairy farmers as well as encourage greater use of pastures in Wisconsin and Minnesota.

Objectives/Performance Targets

• Quantify growth rate, seasonal distribution of yield, species composition, and nutritive value of improved grass-legume mixtures.
  Quantify sward density of grasses and grass-legume mixtures over the grazing season.
  Develop strategies to improve legume contributions to pasture during establishment.
  Understand limitations to greater use of legumes in pastures by farmers.
  Extend information about grass-legume mixtures to farmers.

Accomplishments/Milestones

• Sampling of grass-legume mixtures at 28 day (tall fescue, meadow fescue, orchardgrass, Kentucky bluegrass) or 35 day (smooth bromegrass, reed canarygrass, quackgrass) was completed in Wisconsin and Minnesota.
  Data collected include total season yield, seasonal distribution of yield, and sward density.
  Samples for forage quality analysis (CP, NDF, IVTD) and species composition (via NIRS) were collected.
  Laboratory analysis for forage quality and species composition were completed. Data organization and analysis were completed.
  Initiated a farmer survey to understand farmers perceptions, successes, and failures with legumes in pastures.

Impacts and Contributions/Outcomes

• Presented a 3 hour lecture to the Pasture Management Short Course on Pasture Legumes (10 people attended).
  Grass-legume mixtures were discussed at a pasture walk on a farm in northwest Wisconsin (40 people attended).
  Daniel Collucci wrote and defended MS thesis: Canopy structure, nutritive value, and seasonal distribution of yield of cool season grasses and grass-clover mixtures.
  Presented a 1.5 hour pasture talk (in the field) to 34 students in the International Farmers Aid Association Midwest Summer Short Course.
  Shared knowledge of pasture legumes with Nicaraguan farmers and consultants through Farmer to Farmer, USAID program.
  Barker, D.J., F.P. Ferraro, R.L.G. Nave, R.M. Sulc., F. Lopes, and K.A. Albrecht. 2010. Analysis of herbage mass and herbage accumulation rate using Gompertz equations. Agron. J. 102:849-857.
  Riday, H. and K.A. Albrecht. 2010. Registration of Kura1 Trifolium ambiguum (M.Bieb) germplasm. J. Plant Reg. 4:80-85.

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