Location: Dairy Forage Research
2024 Annual Report
Objectives
1. Develop or improve annual and/or perennial forage production systems that optimize forage production for dairy farms while reducing environmental impacts.
1A. Evaluate management factors for warm-season grass species to develop forage production systems for dairy farms.
1B. Determine manure source and application rate effects on warm season grass productivity, nutritive value, and persistence, and on soil chemical and biological properties.
1C. Determine management and plant biological factors contributing to winterkill and poor persistence of alfalfa and develop strategies to reduce winterkill and improve persistence of alfalfa.
2. Develop or improve warm-season and/or cool-season grass germplasm that enhances yield, quality and resiliency of forage production for integrated dairy systems.
2A. Develop, validate, and apply genomic selection tools to be used in breeding switchgrass for improved forage/biomass yield, cold tolerance, nitrogen-use efficiency, and digestibility.
2B. Determine the role of endophytic fungi in the meadow fescue life cycle.
3. Develop or improve forage legume germplasm that enhances yield, quality and resiliency of diverse forage management systems.
3A. Develop improved red clover varieties that have greater persistence and biomass yield.
3B. Develop improved alfalfa germplasms that are genetically broad and will expand the U.S. alfalfa breeding pool.
3C. Improve underutilized forage legumes for use in forage production and as cover crops.
4. Develop or improve cover crop systems that enhance forage production while reducing nutrient losses and soil erosion in integrated dairy production systems.
4A. Refine management practices for corn grown with interseeded alfalfa.
4B. Develop or identify germplasm that is well suited for interseeding.
5: Develop ration formulation and feeding strategies that experimentally validate chemical methods designed to properly value use of alfalfa in terms of animal performance, milk production, nutrient use efficiency, and enteric methane emissions.
6: Develop cover crop strategies (and tools) for the upper Midwest that explore new plant species and overcome current soil moisture, soil temperature, crop pest and economic limitations to provide incentive to farmers to adopt cover cropping.
Approach
Objective 1. Switchgrass, big bluestem and indiangrass cultivars will be fertilized with 0 to 80 kg/ha of fertilizer nitrogen and harvested once or twice per season to assess plant development, dry matter yield and forage quality in relation to nutrient requirements of dairy cattle. The warm season grasses will also be fertilized with 0 to 80 kg of nitrogen in the form of solid and liquid manure to assess nutrient uptake, soil chemical and biological properties, plant persistence, dry matter yield and nutritive value.
Objective 2. Genomic selection tools will be developed, validated, and used in breeding switchgrass for improved forage/biomass yield, cold tolerance, nitrogen-use efficiency, and digestibility. The role of endophytic fungi in conferring drought, heat, defoliation, and traffic tolerance to meadow fescue will be assessed in greenhouse and field experiments.
Objective 3. An extensive breeding program utilizing phenotypic and genotypic selection of halfsib lines grown as spaced plants and swards at multiple locations will be used to develop red clover cultivars with improved biomass production and persistence. Four alfalfa subsp. falcata syn1 germplasms developed by recurrent phenotypic selection will be harvested for multiple years in sward trials to assess persistence and dry matter yield. Two experimental birdsfoot trefoil varieties differing in tannin content and 15 experimental kura clover varieties will be compared to check varieties in sward trials to assess growth characteristics, dry matter yield, persistence, and forage quality.
Objective 4. Field studies will evaluate and refine agrichemical applications as well as planting and harvesting management practices to improve the establishment and overall forage production of alfalfa interseeded into silage corn. Syn1 and hybrid alfalfa entries developed from surviving plants and various corn hybrids will be evaluated in field studies to evaluate their compatibility and dry matter yield potential in a corn silage-interseeded alfalfa production system.
Objective 5. This objective will be fulfilled by conducting the following types of experiments:
1. Quantify the nutritional benefits of alfalfa and its interactions with other feed components when fed in various kinds of dairy rations and understand how protein, fiber, and other constituents in alfalfa are metabolized in the rumen and utilized for milk production vs. other less desirable outcomes such as enteric methane emissions.
2. Improve forage quality assays to more accurately predict the nutritive value of alfalfa and optimize its use in dairy rations.
Objective 6. Research will focus on incorporating plants beyond alfalfa into existing crop rotations with outcomes that incentivize farmers to adopt cover cropping practices (e.g., improved crop production as mediated by soil health, water use efficiency or provision of nutrients that is more economical than application of chemical fertilizer; increased forage availability for livestock beyond that produced by conventional cropping systems; increased provision of environmental services such as pollinator habitat, soil conservation or soil carbon storage).
Progress Report
This is the final report for this project which terminated in January 2024. See the report for the replacement project, 5090-21500-002-000D, “Developing Sustainable Forage and Cover Crop Systems for Dairy Farms” for additional information.
Objective 1: No progress report due to scientist retirement during fiscal year 2019.
Objective 2: During this project, highly accurate genomic selection protocols were developed for a wide range of switchgrass populations that represent both biomass and forage types. Application of these protocols to several populations revealed that late flowering and improved winter survivorship were the two key traits that allowed the development of populations with superior biomass yield in the northern USA. Across a broad landscape, late flowering and improved winter survivorship have a strong negative genetic correlation, but this correlation can be partially broken or relaxed by intensive selection. Genetically similar meadow fescue populations with or without the endophytic fungus were evaluated for tolerance to three environmental stresses: heat, drought, and a combination of frequent and low defoliation. The endophyte had no impact on either heat or drought tolerance but increased the tolerance of meadow fescue to frequent and low defoliation over a 3-year period in field experiments.
Objective 3: During this project nine experimental red clover varieties were created (DFRC19, DFRC20, DFRC21, DFRC25, DFRC26, DFRC27, DFRC28, DFRC29, and DFRC30). These potential varieties are available for further testing and commercialization. Four alfalfa germplasms were fully evaluated and are ready for submission to NPGS (CASIA, OTTM, EURO, and SIBR). Two divergently selected birdsfoot trefoil experimental varieties were evaluated for agronomic performance and tannin content (MSP4067 and MS4068). These two birdsfoot trefoil experimental varieties are ready for release as cultivars. Finally, 15 experimental kura clover varieties were evaluated for agronomic traits. The 15 experimental kura clover varieties are ready for release as cultivars (ARL16-K01, ARL16- K02, ARL16-K03, ARL16-K04, ARL16-K05, ARL16-K06, ARL16-K07, ARL16-K08, ARL16-K09, ARL16-K10, ARL16-K11, ARL16-K12, ARL16-K13, ARL16-K14, and ARL16-K15).
Objective 4: Five studies investigating the interseeding of alfalfa into corn as a dual-purpose cover and forage crop were conducted during this project. The first study, conducted in conjunction with ARS researchers in Kimberly, Idaho, evaluated alfalfa establishment by interseeding compared to alfalfa establishment by conventional methods. A second study identified hybrid traits associated with yield drag of corn grown with interseeded alfalfa. A third study examined how the timing of alfalfa interseeding and the timing of corn harvest influenced the yield of corn silage and the establishment and initial yield of alfalfa. A fourth project examined plant survival and disease resistance characteristics of public and seed industry alfalfa germplasm subjected to recurrent selection under corn; work on this project will continue under the replacement project, 5090-21500-002-000D, “Developing Sustainable Forage and Cover Crop Systems for Dairy Farms.” The fifth study examined how the application of protective agrichemicals on interseeded alfalfa impacted the establishment of alfalfa and yield of corn on farms in various locations in Wisconsin; this work was carried out by the University of Wisconsin-Madison through a cooperative agreement.
Objective 5: Two studies were completed during this project to evaluate the inclusion level or quality of alfalfa silage in lactating dairy cow diets. The high alfalfa silage diet replaced corn silage as the main forage ingredient. Feed conversion efficiency, defined as a unit of energy-corrected milk per unit of feed consumed, was greater for cows fed the high alfalfa silage diet compared to cows fed the low alfalfa silage diet. Other than for dry matter intake, there were no interactions between breed of cattle and type of diet. Cows fed the low alfalfa diet were more efficient in converting nitrogen to milk protein than cows fed the high alfalfa diet because of difference in rumen protein degradability. However, the conversion of feed to milk was greater for cows fed the high alfalfa silage diet compared to the low alfalfa silage diet. In the second study, the impact of fiber digestibility of two varieties of alfalfa harvested at two different maturities on lactation performance, milk composition, and feed conversion efficiency of lactating dairy cows was evaluated. Conventional and reduced- lignin alfalfa was harvested at bud and mid-flowering stage and then fed to high producing dairy cows to evaluate differences in fiber digestibility on lactation performance. Cows fed early cut alfalfa produced more energy- corrected milk than cows fed the late-cut alfalfa silage, but production was not affected by the variety of alfalfa included in the diet. Feed conversion efficiency was the highest for both early-cut alfalfa varieties and for the late- cut reduced-lignin alfalfa variety and was the lowest for the late-cut conventional alfalfa variety.
Objective 6: Three studies focused on integrating cover crops and precision agriculture technology and management approaches to enhance agronomic and environmental benefits in dairy forage systems were conducted or continued during this CRIS project. The first study, conducted at Prairie du Sac, Wisconsin in conjunction with a University of Wisconsin-Madison researcher through a cooperative agreement, focused on the use of UAV-acquired muti- and hyperspectral imagery and publicly available satellite imagery to estimate alfalfa forage production, quality, and field-scale variability. The second study, also conducted at Prairie du Sac in conjunction with a University of Wisconsin-Madison researcher, evaluated the impact of controlled wheel traffic on soil compaction and alfalfa productivity at field-scale. The third project, which will continue under the replacement project, 5090-21500-002-000D, “Developing Sustainable Forage and Cover Crop Systems for Dairy Farms,” is being conducted at two sites in Wisconsin and is evaluating alternatives to winter cereal rye monocultures for winter cover crop systems in dairy production systems. The biodiversity portion of this work was carried out by the University of Wisconsin-Madison through a cooperative agreement.
Accomplishments
Review Publications
Grabber, J.H., Dias, J.C., Renz, M.J. 2023. Establishment of alfalfa intercropped under corn in response to varying rates of prohexadione with or without fungicide plus insecticide. Agronomy. https://doi.org/10.3390/agronomy13112823.
Grabber, J.H., Bjorneberg, D.L., Rogers, C.W. 2024. Intercropping in maize silage verses solo-seeding for alfalfa establishment in Wisconsin and Idaho. Crop Science. https://doi.org/10.1002/csc2.21189.
Tilhou, N.W., Kucek, L.K., Carr, B., Marion, A., Douglas, J., Englert, J., Ali, S., Raasch, J.A., Bhamidimarri, S., Mirsky, S.B., Monteros, M.J., Krogman, S., Hayes, R.J., Azevedo, M.D., Riday, H. 2023. Genome-wide association mapping in hairy vetch (Vicia villosa) discovers a large effect locus controlling seed dormancy. Frontiers in Plant Science. https://doi.org/10.3389/fpls.2023.1282187.