Location: Environmentally Integrated Dairy Management Research
2023 Annual Report
Objectives
Objective 1: Develop land and manure management practices to improve crop and forage productivity, quality, and nutrient use efficiency.
Objective 2: Reduce nutrient losses from replacement dairy heifer production through management strategies that target nutrient use efficiency and growth performance.
Objective 3: Develop or improve annual and/or perennial forage production systems that optimize forage production for dairy farms while enhancing soil health.
Objective 4: Incorporate cropping systems and agronomic management system effects on soil health into whole-farm dairy simulation models.
Approach
Pressures facing modern dairy operations, including high input costs, and uncertain milk and commodity prices have led to renewed interest in less intensive production practices. Improvements in the production efficiencies in dairy production can impact sustainability of dairy operations. The proposed research will focus on impacts of utilization of perennial forages, as well as novel annual species for providing alternative uses in modern dairy operations. The approach is collaborative, including contributions from the University of Wisconsin Marshfield Agricultural Research Station (UW-MARS), UW-Madison, UW-Extension, USDA-NRCS, and the University of Florida, among others. The approach also consists of experimental field work. Field work is based on continued use and development of field facilities at UW-MARS. This work impacts dairy and forage production systems in the upper Midwest and elsewhere. Products and outcomes consist of best management practices for grazing and forage management; fundamental knowledge about soil health and function, and forage productivity; and environmental impacts of grazing production. Stakeholders include dairy or beef cattle producers, extension agents, as well as other public agencies.
Progress Report
In support of Objective 1, researchers at Marshfield, Wisconsin, evaluated a microbial inoculant as a mitigant of clostridial products in high-moisture, grass-legume baled silages from pastures that were fertilized with dairy slurry. This research is important for identifying strategies for reducing clostridial fermentation products, since these can be exacerbated by exceeding normal moisture targets (45% to 55%). The team conducted two separate studies to evaluate the effectiveness of the microbial inoculant after a 4-month or 9-month storage period of baled silage. Results from the 4-month storage period indicated that despite the application of dairy slurry, as well as greater-than-recommended bale moisture, only minimal concentrations of typical clostridial products were observed following fermentation in either treatment. The lack of clostridial response might be explained by numerous strong rainfall events during the growth of these forages, prompt wrapping following baling, substrate adequacy, as well as an exceptionally low buffering capacity. As a result, using a combination hetero- and homolactic inoculant to mitigate clostridial activity was inconclusive. These results have been published in a peer-reviewed journal. For the second study, all samples have been collected and analyzed. The research team is currently undertaking the statistical analysis and working on the peer-reviewed publication for submission in fiscal year 2023. Results indicate that the use of a microbial inoculant can reduce heating when silage bales are opened which would reduce feeding losses for livestock producers.
In support of Objective 2, Goal 1, researchers at Marshfield, Wisconsin, established a grazing experiment to evaluate the pasture characteristics and dairy heifer performance on contrasting grazing systems consisting of meadow fescue with nitrogen fertilizer, meadow fescue with no nitrogen fertilizer, and meadow fescue with clovers. The pastures were planted in Fall 2022 at the Marshfield Agricultural Research Station. Data collection commenced in May 2023, and will occur for two consecutive years.
For Objective 2, Goal 2, researchers at Marshfield, Wisconsin, evaluated 10 experimental lines (UF1-UF10) of a black oat (Avena strigosa) germplasm and a commonly available variety ('Ogle') of oat (Avena sativa) for forage productivity and nutritive value in central Wisconsin. Black oats are commonly used as a cover or forage crop in parts of South America and are currently recommended for forage use in southeastern U.S. regions, where the climate is mild and winters are short. However, black oat might be an attractive option as a forage species for the upper Midwest, for use during the summer, provided that black oat is heat resistant and disease tolerant. Data were collected over two consecutive years, and all samples have been processed and analyzed for nutritive value and chemical composition. There were differences in forage accumulation and nutritive value within the 10 black oat lines evaluated in this experiment. Overall, the results indicate certain black oat lines have the potential to provide forage resources during the early summer in the upper Midwest, but further studies are warranted to evaluate how to best manage this species into cropping or pasture systems in the region. This data will be used for species selection and future commercial cultivar releases. A scientific publication is currently being prepared and will be submitted to peer-reviewed journal in fiscal year 2023.
In support of Objective 3, researchers at Marshfield, Wisconsin evaluated the productivity and quality of mixtures of forage crops at two locations in Wisconsin. Such forage mixtures are becoming increasingly used by dairy farms to allow for use of manure on the growing crop to better use the manure nutrients, and to help control insects that are common when producing multiple years of corn. In fiscal year 2023, the second year of forage plots were established, harvested, and samples analyzed for nutritive value, with a third/final year of plots now established for evaluation in summer 2023. A scientific publication will be prepared after laboratory and statistical analysis of the third year of plot data and submitted to a peer-reviewed journal in fiscal year 2024.
For Objective 4, we have no progress to report as the scientist responsible for this work has not been hired as of this report. The hiring process for the scientist is currently underway with plans for hiring/on-boarding in late fiscal year 2023.
Accomplishments
1. Use of a silage inoculant with baled silage reduces silage heating after opening for long term (9 months) silage. Feed losses can be high for livestock producers after opening of silage structures due to heat generated by aerobic fermentation when silage is exposed to air. Use of mixed fermentation (lactic acid and acetic acid producing bacteria) inoculants in corn silage has shown reduced spoilage after opening due to the acetic acid inhibiting yeast activity, but limited work has been done with baled/wrapped silage. ARS researchers in Marshfield, Wisconsin, evaluated the use of a mixed fermentation inoculant in baled silage in two studies with different storage timeframes (4 or 9 months). In both studies, use of an inoculant had no effect on silage forage nutritive value. In the 4-month study, inoculation did not affect silage stability. In the 9-month study, untreated bales heated in 4-5 days after opening, while inoculated bales were stable for 9-10 days. This work provides dairy and livestock producers, and management advisors with knowledge that the use of mixed silage inoculants can help reduce forage losses and better utilize harvested forage resources.
2. Evaluation of a black oat (Avena strigosa) germplasm in the upper Midwest. Black oat is more heat tolerant and disease resistant than other cool-season grasses, which makes them an attractive option for the upper Midwest, but their use has not been well investigated. ARS scientists in Marshfield, Wisconsin, in partnership with scientists from the University of Florida and Louisiana State University, evaluated 10 experimental lines (UF1-UF10) of a black oat germplasm for forage production and nutritive value when grown in the upper Midwest during the summer. Over two consecutive years, two of the 10 black oat germplasm lines were able to produce greater forage biomass than ‘Ogle’ oat (Avena sativa), which is a locally-available variety of the more commonly-used, forage-type oat. No consistent differences were observed in forage nutritive value. This work provides forage breeders with data relevant to species and variety selection for production in the Midwest. Black oat forage can provide Midwest livestock producers an option to improve forage resources for use during the summer for grazing or harvest.
Review Publications
Santos, E., Dubeux, J., Queiroz, L., Jaramillo, D.M., Garcia, L., van Cleef, F., de Abreu, D., Ruiz-Moreno, M. 2022. Seeding rate affects the performance of oat and black oat. Crop, Forage & Turfgrass Management. 8(2). https://doi.org/10.1002/cft2.20192.
Coblentz, W.K., Akins, M., Jaramillo, D.M., Cavadini, J. 2022. Nutritive value, silage fermentation characteristics, and aerobic stability of grass-legume round-baled silages at differing moisture concentrations with and without manure fertilization and microbial inoculation. Journal of Animal Science. 100(11). https://doi.org/10.1093/jas/skac325.
