Research Project: Improving Nutrient Use Efficiency and Mitigating Nutrient and Pathogen Losses from Dairy Production Systems

Location: Environmentally Integrated Dairy Management Research

2021 Annual Report

Objectives
Objective 1: Develop land and manure management practices to improve crop and forage productivity, quality, and nutrient use efficiency; and reduce pathogens and losses of nutrients. Sub-objective 1.A. Conduct multi-scale experiments to investigate biochemical and physical processes controlling snowmelt, snowmelt infiltration and runoff, and nutrient losses from soil and manure. Sub-objective 1.B. Evaluate nutrient cycling, nitrous oxide and ammonia emissions, and nutrient and pathogen runoff losses with conventional and improved liquid dairy manure management practices for alfalfa production and in a silage corn-rye cover crop system. Sub-objective 1.C. Determine manure/crop management effects on N, P, and pathogens in runoff from dairy cropping systems. Sub-objective 1.D. Evaluate effects of alternative manure application methods on alfalfa-grass yield, quality, and silage fermentation characteristics. Sub-objective 1.E. Determine potential of fall-grown oat to capture nutrients from summer manure or fertilizer applications and produce a late-fall, energy-dense forage crop. Determine potential of spring wheat and barley for fall-forage yield, quality, and nutrient capture from mid-summer manure or fertilizer applications. Evaluate oat mixtures with wheat, triticale or cereal rye (1 planting) for total fall and spring forage yield (2 harvests), as well as nutrient capture. Objective 2. Develop, improve, calibrate, and validate model routines for nutrient management to assess environmental impacts, nutrient use efficiency, and economics at the farm scale. Objective 3: Characterize soil biodiversity and manure pathogen dynamics and interactions. Sub-objective 3.A. Conduct laboratory microcosm experiments to manipulate soil biodiversity and measure die-off rates of dairy manure-borne pathogens. Sub-objective 3.B. Conduct field studies relating agricultural cultivation practices to soil biodiversity and die-off rates of manure-related pathogens. Objective 4. Reduce nutrient losses from replacement dairy heifer production through management strategies that target nutrient use efficiency and growth performance. Sub-objective 4.A. Improve understanding of heifer development and growth, especially effects of genomic testing for residual feed intake (RFI) on nutrient-use efficiency and growth. Sub-objective 4.B. Determine effect of common management strategies (pen stocking rate, limit feeding, ionophores, diet composition, etc.) on nutrient-use efficiency and growth performance of heifers.

Approach
Improved management of dairy farms requires successfully managing its nutrient flows, both to maximize nutrient use by animals and crops to optimize profit, and to minimize nutrient loss to the environment. We will investigate most aspects of nutrient cycling throughout the dairy-farm system with a variety of methods and at different scales, including replicated field plots, field-scale paired watersheds, feeding trials with replicated pens of heifers, and computer modeling. We will also examine pathogen transport and viability at different points in the dairy farm system. Some experiments will investigate only one or two nutrient or pathogen pathways, while others will be more comprehensive, including, for example, surface runoff, gaseous emission, and plant removal. Computer modeling will investigate the whole-farm system. Our research team also has a longer-term goal, which is to integrate information across experiments to more completely describe, quantify, model, and manage the entire dairy-farm for improved efficiency and sustainability. Achieving this goal will help ensure the existence of profitable, environmentally acceptable dairy farming for coming decades.

Progress Report
Objective 1, Subobjective B: Multiple field studies quantifying the impacts of traditional and low-disturbance liquid dairy manure application effects on nutrient loss potential in overland flow (aka., surface runoff), nitrogen leaching, greenhouse gas fluxes and crop performance were completed. Trials were conducted in corn-silage-winter rye and alfalfa forage systems. A total of three peer-reviewed manuscripts have been published related to this subobjective, six national trade journal articles (invited), and two manuscripts were recently submitted. Objective 1, Subobjective C: The treatment phase of the paired watershed experiment was completed. A manuscript evaluating the impacts of manure and nutrient best practices on overland flow water quality among the four watersheds was recently published for the corn silage phase of the rotation. Following another calibration period with all watersheds managed in hay (2012-2018), the influence of dairy heifer grazing regime was tested during 2018-2020. A manuscript is in progress summarizing the grazing management effects on overland flow water quality and soil nutrient dynamics. Objective 1, Subobjective D: Scientist's previous detail as Acting Center Director delayed project initiation; however, dairy slurry was applied to forage regrowth at a rate of 46,000 L/ha in June 2021. Expected harvest of silages should occur in mid-July, with final sampling in November 2021. Objective 1, Subobjective E: Experiments assessing the use of spring barley and wheat for generating emergency fall forage were successful. These forages do not require vernalization for reproductive growth, and yields were comparable or superior to oat. Data from this project has been summarized and published. Studies evaluating mixtures of cereal grains for emergency fall forage, as well as forage the following spring were largely unsuccessful, and the project was discontinued. Objective 3, Goals A and B: We are continuing to compile data from previous experiments and have worked on other studies and publications in the meantime. This project is terminating in FY21. Over the project’s lifetime, our research unit has produced 45 accomplishments, 30-40 presentations per year (technical and extension combined), and published 80 peer-reviewed journal articles. Research topics are broad, including forage production, nutrient runoff and nutrient use efficiency, groundwater quality, and risk assessment for waterborne pathogens. Research collaborations have been similarly broad, including numerous collaborators in Wisconsin and across the U.S. (facilitated by about a dozen incoming and/or outgoing agreements per year) as well as a number of international collaborations in Canada, Finland, Italy, New Zealand, Northern Ireland, and the United Kingdom.

Accomplishments
1. Risk factors related to dairy farming and septic systems identified for private well contamination in northeast Wisconsin. In the past few decades northeastern Wisconsin has seen expansions in dairy farming and rural homes. Both dairy farmers and rural homeowners in this region rely on groundwater from private wells to supply their drinking water. Being rural, fecal wastes from both groups (dairy manure and septic system effluent) are distributed to the landscape. However, the groundwater comes from a type of underground aquifer that is highly connected to the land surface, allowing fecal material to contaminate private wells, and creating tensions between farmers and homeowners. ARS researchers in Madison, Wisconsin, built statistical models that linked private well contamination with risk factors such as how near wells were to manure storage and the number of surrounding septic systems. Rainfall amount and the amount of water able to reach and replenish groundwater were also factors related to contamination. Well construction factors, like well depth, were not as important to contamination as those factors related to land use. Understanding the “what, where, and how” of private well contamination in northeastern Wisconsin presents opportunities for improving groundwater quality to the benefit of farmers and homeowners alike. Moreover, the findings are relevant to the broader region surrounding the Great Lakes of the U.S. and Canada, which is supplied with drinking water from the same aquifer as northeastern Wisconsin.

2. Quantified risk of gastrointestinal illness in private wells contaminated by human septage and dairy manure in the fractured dolomite aquifer of Kewaunee County, Wisconsin. As in other areas of the nation, private wells in Kewaunee County, Wisconsin are an important source of drinking water, and they are vulnerable to contamination by fecal waste from livestock manure and private septic systems due, in part, to the region's fractured dolomite (i.e., karst) aquifer. Fecal waste carries pathogenic microorganisms that can cause acute gastrointestinal illness (AGI) when consumed in water, but the extent of AGI cases caused by drinking water from contaminated private wells in Kewaunee County is currently unknown. With collaborators at the U.S. Geological Survey, ARS researchers at Madison, Wisconsin used quantitative microbial risk assessment and a county-wide pathogen occurrence study to predict the number of AGI cases per year due to contaminated private wells. Their results suggest that consuming contaminated private well water in Kewaunee County could cause as many as 301 AGI cases per year, which corresponds to approximately 4% of expected county-wide AGI cases due to all sources. Approximately 230 of the these predicted cases were potentially associated with bovine fecal material in contaminated wells, while an additional 12 cases were predicted to associate with human fecal sources and 59 cases could not be exclusively associated with either source. This research is useful for estimating the potential health effects of land-use and management changes in Kewaunee County, a region with approximately 12,000 rural residents that obtain their drinking water from private wells.

3. Agronomic and environmental impacts of liquid dairy manure application methods evaluated. Dairy manure is a critical crop nutrient source, however careful management is required to minimize losses and optimize recovery of applied nutrients. ARS researchers at Madison, Wisconsin evaluated impacts of both traditional and low-disturbance dairy manure application methods on crop performance, nutrient runoff loss potential, and greenhouse gas emissions in a corn silage-winter rye and alfalfa cropping system. Compared to broadcasting (manure applied on the soil surface without any incorporation), shallow disk injection significantly decreased dissolved forms of nitrogen and phosphorus in overland flow of alfalfa plots without negatively affecting stand integrity. In the corn system, shallow disk injection retained significantly more nitrogen compared to other methods when fall-applied, with corn silage yields similar to spring applied urea treatments. While shallow disk injection also conserved significantly more available nitrogen, nitrous oxide fluxes were also greater compared to broadcast and aerator-band application. Low-disturbance methods offer the potential to increase overall manure nutrient use efficiency in hay and corn systems in the upper Midwest.

4. Manure nutrient management influences overland flow nutrient loss and runoff water quality in a corn silage-winter rye cover crop system. Erosion and nutrient loss processes from cropland are notoriously spatially and temporally variable, confounding attempts to quantify impacts of best practices. Edge-of-field and small paired watershed designs help account for this variation. Using four small paired watersheds, ARS researchers at Madison, Wisconsin showed the importance of manure and nutrient management practices on the timing and magnitude of nutrient loss in overland flow during four years of corn silage production. In addition to the control practice of fall-applied manure with chisel tillage, management regimes included fall-applied manure with chisel tillage and grass buffer strip, winter rye cover crop with spring-applied manure and tillage, and fall-applied manure with spring chisel tillage (considered least favorable for nutrient loss risk). Compared to the control, the grass buffer treatment reduced sediment, total nitrogen, and total phosphorus concentrations and loads. In contrast, fall-applied manure with spring tillage increased total phosphorus, dissolved phosphorus, and ammonium-nitrogen losses by 39, 376, and 197%, respectively. The winter rye plus spring manure application/tillage reduced sediment, total nitrogen/phosphorus concentrations but not loads. Results indicate the importance of targeting manure applications and tillage to times of the year with lower overland flow risk and the need for additional practices to adequately mitigate dissolved phosphorus loss risk from fields prone to overland flow losses.

5. Fall forage yield of vegetative winter cereals in Wisconsin. Recent emphasis on use of cover crops to improve soil health, limit soil erosion, and alleviate nutrient runoff has increased the use of cereal-grains as forages throughout the north-central U.S. These forages normally possess requirements for cold vernalization, and are subsequently terminated either with a non-selective herbicide treatment in the spring, or by a spring harvest as silage, and then followed by a double-crop of corn or soybeans. ARS researchers at Madison, Wisconsin evaluated the fall (vegetative) forage yield and nutritive value of winter wheat, rye, and triticale cultivars harvested on dates ranging from mid-October through early-December, and subsequently examined the residual effects of fall harvest date on forage regrowth potential the following spring. Fall dry matter yield of winter cereals in central Wisconsin varied with weather conditions, but can approach 1 ton/acre in some years. Utilization of this forage by grazing livestock is likely to be complicated by the potential for pugging of wet, heavy soils, or by the onset of significant lasting snowfall. The nutritive value of these fall forages is excellent, as reported for other parts of the U.S., with no clear advantages attributed to any of the species examined. In particular, concentrations of water-soluble carbohydrates and whole-plant ash appear to be major drivers (positive and negative, respectively) of variations in forage energy density. Fall forage growth of winter cereals could be used for forage in emergency situations.

6. Propionic acid-based preservatives improve aerobic stability of baled silages. Most state-of-the-art balers come equipped with applicator systems for preservatives and/or inoculants, or the option exists for factory installation at the time of purchase. Within this context, propionic acid-based preservatives are available, and are used commonly, as preservatives for storage of dry hay, but not for baled silages. ARS researchers at Madison, Wisconsin tested several application rates of a propionic-acid-based preservative on the storage efficiency, nutrient preservation, fermentation characteristics, and subsequent aerobic stability of alfalfa-grass silages made at two moisture concentrations (51.6 or 43.6%) and damaged by a 0.2-inch rainfall event during wilting. The application of a propionic-acid-based preservative at rates of 0.13, 0.44, or 0.80% of wet weight, executed simply by engaging the different pumping options with the factory-installed applicator, showed some evidence of restricting overall silage fermentation. Preservative application, regardless of rate, was effective at improving the aerobic stability of alfalfa/grass baled silages compared to untreated controls. The 0.44 and 0.80% rates provided better stability than the lowest rate, and on a practical basis, were essentially equivalent within an 11-d exposure period. For a 4 × 4-ft round bale weighing 1250 lbs (50% moisture), about 5.5 lbs of product appeared to provide optimum benefit. While this option adds cost, it still may be a viable tool for overall production management, particularly in targeted situations where periods of exposure to air are likely before consumption by livestock. This may be particularly true during seasonal transitions before or after winter, when warmer temperatures may be less inhibiting of aerobic deterioration.

7. Propionic-acid-based preservatives improve aerobic stability of grass silages. Baled silage techniques offer a forage conservation option that limits risk to valuable hay crops because less wilting time is required to reach normal recommended moisture targets (45 to 55%) compared to dry hay. One issue related to baled silage management occurs during feedout, when silage bales may be exposed to air for various reasons prior to consumption by livestock. This concern can be more problematic for bales wrapped with in-line wrapping systems, where partial or total removal of the plastic wrap prior to transport to the feeding site is unavoidable. ARS researchers at Madison, Wisconsin compared the fermentation characteristics, nutritive value, and aerobic stability of three perennial cool-season grasses (meadow fescue, orchardgrass, and endophyte-free tall fescue) conserved as silages baled at relatively low moisture concentrations (31.1 to 42.1%) with or without a propionic-acid-based preservative. Application of the preservative at rates of 0.48 or 0.77% of wet bale weight provided additional aerobic stability compared to untreated bales after exposure to air. This response was consistent with previous findings for alfalfa-grass baled silages, and provides forage and livestock producers with an additional management tool for use within their operations.

8. Evaluation of warm-season annuals in Wisconsin. Grazing-based dairy operations require productive, high-quality forages capable of supporting the nutritional needs of mid-lactation dairy cows. ARS researchers at Madison, Wisconsin evaluated weekly harvests of two cultivars of sudangrass (SU), sorghum-sudangrass (S×SU), and pearl millet (PM) forages for growth and nutritive characteristics for grazing by dairy cows. For the cultivars evaluated in this trial, dry matter yields were less consistent at the more northern (Wisconsin) experimental location (Marshfield), which also is known for heavy, poorly drained soils. Despite locational differences, taller-growing cultivars within each forage type frequently exhibited yield advantages over dwarf or shorter-growing cultivars, but shorter cultivars often exhibited greater percentages of leaf across harvest dates, which is especially relevant within a grazing application. Consistent with these generalizations, PM cultivars exhibited shorter canopy heights and greater percentages of leaf than other cultivars, but these responses were generally associated with a yield drag. However, the greater leaf percentages for PM cultivars did not result in reduced percentages of structural plant fiber on a whole-plant basis. Despite this observation, fiber digestibility was often significantly greater for PM compared to other cultivars. Within the conditions established for this trial, PM cultivars generally exhibited more suitable characteristics for grazing livestock than SU or S×SU cultivars, but this management choice will likely come at a cost with respect to yield.

9. Use of spring barley and wheat for fall forage in Wisconsin. Recent emphasis on use of cover crops to improve soil health, alleviate nutrient runoff, and limit soil erosion has increased interest in using cereal-grains as forages throughout the north-central U.S. ARS researchers at Madison, Wisconsin evaluated early- and late-maturing cultivars of oat, spring wheat, and spring barley in central Wisconsin for fall-forage production and nutritive value when forages were established in August and harvested in early November. The results of this study establish that spring cultivars of wheat or barley that do not have an obligatory requirement for vernalization can be used for fall production of forage, and will perform similarly to oat in this respect. The barley cultivars evaluated in this trial generally exhibited superior nutritive value compared to wheat cultivars, largely because they exhibited evidence of significant grain fill. Further work is needed to develop management strategies, such as establishment and harvest timing, that will provide the best trade-offs between dry matter yield and nutritive value for spring barley or wheat. However, best management practices will be dependent on cultivar, maturity designation, and the nutrient requirements of the livestock class supported.

10. Effects of feed push-up frequency on the growth performance of limit-fed gravid heifers. Conceptually, there are two feeding strategies for avoiding over-conditioning that can be problematic for gravid dairy heifers that have reduced dietary energy density requirements relative to younger animals. These strategies include: i) dilution of the ad-libitum-fed diet with low-energy forages; or ii) offering a diet of greater nutrient density, but intentionally restricting the dry matter available for consumption (limit-feeding). ARS researchers at Madison, Wisconsin evaluated the effects of feedbunk restriction and feed push-up frequency on the growth performance of gravid Holstein dairy heifers. A 2 × 2 factorial arrangement of treatments was assigned; treatments consisted of feedbunk access [full (FUL) or restricted (RES] and feed push-up frequency [1.5 or 3.0-h intervals]. The RES treatment was applied by covering two of the eight head-locking feed gates in assigned pens with plywood partitions, thereby creating a feedbunk stocking rate of 133%. A TMR diet comprised of alfalfa haylage (60.5%), corn silage (38.0%), and mineral (1.5%) was offered once daily for 91 d; daily feed allotments (overall mean = 9.11 kg DM/d) were generally consumed entirely within 9 h after feeding. After 91 d, heifers without feedbunk restriction exhibited greater final bodyweights, but total gain and average daily gain differed only numerically between FUL and RES. Under the conditions of this trial, heifers were blocked by weight, such that bodyweights were relatively uniform within each pen, and head-locking feed gates were used, which also provided some protection from adjacent aggressive heifers. These results suggest heifers can exhibit acceptable growth performance on high-forage diets in a limit-feeding program that includes moderate feedbunk restriction provided other forms of stress are minimized.

11. Effectiveness of propionic-acid-based preservatives on alfalfa hays. Past studies have demonstrated that the effectiveness of propionic-acid-based hay preservatives vary considerably, with effectiveness being greater with smaller bales. ARS researchers at Madison, Wisconsin compared spontaneous heating responses within 5-ft diameter round bales of alfalfa hay that were either treated with a propionic-acid-based preservative (TREATED), or not treated with the preservative (CONTROL). Twenty-eight bales were made at 20.2% moisture; TREATED hays received 4.0 ± 0.57 lbs acid preservative/ton, which was consistent with product recommendations. Bales were stored outdoors on wooden pallets for 65 days, and internal bale temperatures were monitored daily. Overall, preservative application in large-round bales of alfalfa hay reduced spontaneous heating, and improved dry matter recovery, as well as some nutritive analytes compared to CONTROL hays. However, these improvements were modest, and raise further questions about whether application rates should be increased for large bale packages.

12. Quantified Legionella and Mycobacterial infection risk due to stagnant premise water after the COVID-19 shutdown. The COVID-19 pandemic resulted in abrupt and prolonged closures of buildings nationwide, including numerous facilities related to food and livestock production. These closures allowed opportunity for pathogens like Legionella and Mycobacterium avium complex (MAC) to grow and multiply in premise plumbing. Following re-occupancy of previously closed buildings, exposure to these pathogens through regular water use could result in increased risk relative to non-pandemic conditions, but the magnitude of this risk and efficacy of potential interventions is not well understood. With collaborators at the University of Minnesota, ARS researchers at Madison, Wisconsin quantified Legionella and MAC concentrations and used quantitative microbial risk assessment to forecast their corresponding health risks in premise plumbing of several buildings in Minneapolis and St. Paul, Minnesota. Overall, estimated health risks were relatively low compared to acceptable risk thresholds, except for scenarios where a large percentage of Legionella were assumed to have an infectivity comparable to L. pneumophila. Furthermore, flushing hot and cold water lines for 15 minutes tended to reduce predicted risk. This study provides data informing risk mitigation for stagnant water in premise plumbing nationwide, including food and livestock production facilities shut down for prolonged periods of time due to the COVID-19 pandemic.

13. Stormwater capture system evaluated for reducing microbial and pharmaceutical contaminants in groundwater. Stormwater runoff in urban areas can pollute nearby surface water (lakes and rivers) with microorganisms and household products such as cleaners and artificial sweeteners. To prevent runoff from reaching surface water one idea is to capture it and place it underground to be filtered by soil. ARS researchers in Madison, Wisconsin studied a stormwater capture system in Minneapolis, Minnesota and measured the pollutants as they moved downward through the soil and into groundwater. Pollutant concentrations in the soil and groundwater beneath the capture system were less than the original concentrations in the stormwater. Concentrations decreased as the pollutants moved downward. However, when it rained the concentrations of microorganisms were not as effectively diminished. The capture system was located at a site with fine-grained soils, which improved pollutant reduction. Other stormwater capture systems located at sites with more vulnerable groundwater may not be as effective. Drinking water for urban residents is often supplied by groundwater pumped from wells located in the city. The information gained from this study will help with locating urban stormwater capture systems in ways that avoid contaminating nearby drinking water wells.

14. Moving from an intermittent to continuous water supply in Nagpur, India improves microbial water quality. The country of India is in the process of improving its drinking water infrastructure so that urban households have access to water continuously. In other words, water will be available whenever a household’s tap is turned on. That is not the case now in any of India’s urban centers. The water supply to households is intermittent, sometimes on, sometimes off. In those water districts of Nagpur where water is supplied continuously, ARS researchers in Madison, Wisconsin showed the water was less frequently contaminated with fecal microorganisms compared to districts with intermittent water supplies. In addition, there were fewer pathogens in the water from continuous-supplied districts, meaning there were likely fewer waterborne infections. Demonstrating that continuous-supplied water has higher sanitary quality can help support decisions on making investments in infrastructure improvementstent water supplies. In addition, there were fewer pathogens in the water from continuous-supplied districts, meaning there were likely fewer waterborne infections. Demonstrating that continuous-supplied water has higher sanitary quality can help support decisions on making investments in infrastructure improvements.

Review Publications
Sherman, J.F., Young, E.O., Jokela, W.E., Casler, M.D., Cavadini, J. 2020. Influence of soil and manure management practices on surface runoff phosphorus and nitrogen loss in a corn silage production system: A paired watershed approach. Soil Systems. https://doi.org/10.3390/soilsystems5010001.
Coblentz, W.K., Akins, M.S., Cavadini, J.S. 2020. Fall dry matter yield and nutritive value of winter rye, wheat, and triticale cultivars in Wisconsin. Crop, Forage & Turfgrass Management. https://doi.org/10.1002/cft2.20075.
Hozalski, R.M., Lapara, T.M., Zhao, X., Kim, T., Waak, M.B., Burch, T.R., Mccarty, M. 2020. Flushing of stagnant premise water systems after the COVID-19 shutdown can reduce infection risk by legionella and mycobacterium spp. Journal of Environmental Science and Technology. https://doi.org/10.1021/acs.est.0c06357.
De Dambert, J.R., Walsh, J.F., Scher, D.P., Firnstahl, A.D., Borchardt, M.A. 2021. Microbial pathogens and contaminants of emerging concern in groundwater at an urban subsurface stormwater infiltration site. Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2021.145738.
Coblentz, W.K., Akins, M.S. 2021. Nutritive value, silage fermentation characteristics, and aerobic stability of round-baled, alfalfa-grass forages ensiled at 2 moisture concentrations with or without a propionic-acid-based preservative. Applied Animal Science. https://doi.org/10.15232/aas.2020-02128.
Young, E.O., Ross, D.S., Jasi, D.P., Vidon, P.G. 2021. Phosphorus transport along the cropland–riparian–stream continuum in cold climate agroecosystems: A review. Soil Systems. https://doi.org/10.3390/soilsystems5010015.
Andriarimalala, J., Dubeux, J., Dilorenzo, N., Jaramillo, D.M., Rakotozandriny, J.S., Salgado, P. 2020. Use of n-alkanes to estimate feed intake in ruminants: a meta-analysis. Journal of Animal Science. https://doi.org/10.1093/jas/skaa304.
Andriarimalala, H., Dubeux, J., Jaramillo, D.M., Rakotozandriny, J., Salgado, P. 2021. Using n-alkanes to estimate herbage intake and diet composition of cattle fed with natural forages in Madagascar. Animal Feed Science and Technology. https://doi.org/10.1016/j.anifeedsci.2020.114795.
Bleier, J.S., Coblentz, W.K., Kalscheur, K., Panke-Buisse, K., Brink, G.E. 2020. Evaluation of warm season annual forages for forage yield and quality in the north-central United States. Translational Animal Science. 4(3). Article txaa145. https://doi.org/10.1093/tas/txaa145.
Bivins, A., Lowry, S., Wankhede, S., Hajare, R., Murphy, H., Borchardt, M.A., Labhasetwar, P., Brown, J. 2021. Microbial water quality improvement associated with transitioning from intermittent to continuous water supply in Nagpur, India. Water Research. https://doi.org/10.1016/j.watres.2021.117301.
Borchardt, M.A., Stokdyk, J.P., Kieke, B.A., Muldoon, M.A., Spencer, S.K., Firnstahl, A.D., Bonness, D.A., Hunt, R.J., Burch, T.R. 2021. Sources and risk factors for nitrate and microbial contamination of private household wells in the fractured dolomite aquifer of northeastern Wisconsin. Environmental Health Perspectives. https://doi.org/10.1289/EHP7813.
Burch, T.R., Stokdyk, J.P., Spencer, S.K., Kieke, B.A., Firnstahl, A.D., Muldoon, M.A., Borchardt, M.A. 2021. Quantitative microbial risk assessment for contaminated private wells in the fractured dolomite aquifer of Kewaunee County, Wisconsin. Environmental Health Perspectives. https://doi.org/10.1289/EHP7815.
Coblentz, W.K., Akins, M.S., Cavadini, J.S. 2020. Dry matter yield and nutritive value of early- or late-maturing spring wheat, spring barley, and oat cultivars planted in late summer. Crop, Forage & Turfgrass Management. 2020;6;e20034. https://doi.org/10.1002/cft2.20034.
Coblentz, W.K., Akins, M.S., Cavadini, J.S. 2021. Nutritive value, silage fermentation characteristics, and aerobic stability of 3 round-baled, perennial-grass forages ensiled with or without a propionic-acid-based preservative. Applied Animal Science. https://doi.org/10.15232/aas.2021-02157.
Coblentz, W.K., Akins, M.S., Esser, N.M. 2020. Effects of feedbunk restrictions and push-up frequency on the growth performance of Holstein dairy heifers offered a forage-based diet with a limit-feeding strategy. Journal of Dairy Science. 103:7000-7008. https://doi.org/10.3168/jds.2020-18152.
Coblentz, W.K., Akins, M.S., Kieke, B.A. 2020. Storage characteristics and nutritive value of moist large-round bales of alfalfa or alfalfa-grass hay treated with a propionic-acid-based preservative. Applied Animal Science. 36:455-470. https://doi.org/10.15232/aas.2020-02024.
De Lira, K., Dubeux, J., De Andrade Lira, M., Carvalho, F., Santos, M., Cunha, M., Mello, A., Jaramillo, D.M., Neto, J. 2021. Tracing sheep binary C3–C4 diet using stable isotope ratio (d13C). Italian Journal of Animal Science. https://doi.org/10.1080/1828051X.2021.1881413.
Ferrer, J., Da Cunha, M., Dos Santos, M., Torres, T., Da Silva, J., Veras, R., Da Silva, D., Da Silva, A., Queiroz, L., Ferrer, M., Neto, E., Jaramillo, D.M., De Souza, E. 2021. Mesquite (prosopis juliflora) extract as a phytogenic additive for sheep finished on pasture in the semiarid region. Chilean Journal of Agricultural Research. https://doi.org/10.4067/S0718-58392021000100014.
Garcia, L., Dubeux, J., Sollenberger, L., Vendramini, J., Dilorenzo, N., Santos, E., Jaramillo, D.M., Ruiz-Moreno, M. 2021. Nutrient excretion from cattle grazing nitrogen-fertilized grass or grass-legume pastures. Agronomy Journal. https://doi.org/10.1002/agj2.20675.
Jaramillo, D.M., Dubeux, J., Sollenberger, L., Mackowiak, C., Vendramini, J., Dilorenzo, N., Queiroz, L., Santos, E., Garcia, L., Ruiz-Moreno, M., Van Santen, E. 2021. Litter mass, deposition rate, and decomposition in nitrogen-fertilized or grass-legume grazing systems. Crop Science. https://doi.org/10.1002/csc2.20475.
Niyigena, V., Coffey, K., Coblentz, W.K., Philipp, D., Rhein, R., Caldwell, J., Shanks, B. 2021. Nitrogen balance and blood urea nitrogen by gestating sheep offered alfalfa silage wrapped with or without an enhanced oxygen barrier plastic after time delays up to three days. Small Ruminant Research. https://doi.org/10.1016/j.smallrumres.2021.106355.
Santos, E., Dubeux, J., Mackowiak, C., Blount, A., Sollenberger, L., Jaramillo, D.M., Garcia, L., Abreu, D., Souza, R., Ruiz-Moreno, M. 2021. Herbage responses and nitrogen agronomic efficiency of bermudagrass-legume mixtures. Crop Science. https://doi.org/10.1002/csc2.20552.
Sherman, J.F., Young, E.O., Jokela, W.E., Cavadini, J. 2021. Impacts of low-disturbance dairy manure incorporation on ammonia and greenhouse gas fluxes in a corn silage–winter rye cover crop system. Journal of Environmental Quality. https://doi.org/10.1002/jeq2.20228.
Jaramillo, D.M., Dubeux, J., Sollenberger, L., Vendramini, J., Mackowiak, C., Dilorenzo, N., Garcia, L., Queiroz, L., Santos, E., Homem, B., Van Cleef, F., Ruiz-Moreno, M. 2021. Water footprint, herbage, and livestock responses for N-fertilized grass and grass-legume grazing systems. Crop Science. https://doi.org/10.1002/csc2.20568.