Location: Environmentally Integrated Dairy Management Research
2019 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
For our established Arlington field site with 5x15-m field plots, we completed the third winter of runoff collection and analyzed and compiled data. Manure application treatments changed from a timing variable (December and January) to a manure solids variable (high and low solids applied in January). We published 2 manuscripts based on the first two years of runoff data. All lab-scale experiments for the project have been completed and results published. We completed a third year of small-scale field experiments to examine the impact of manure solids content on nutrient loss in runoff during snowmelt to see if manure with greater solids content lose less nutrients. In total, we now have 5 site-years of data from both Wisconsin and Minnesota. We are analyzing data for publication and developing model routines.
Due to heavy soils and unfavorable winter/spring weather and flooding, alfalfa stands have been severely damaged. Experiment investigating effects of alternative manure application methods on alfalfa-grass yield, quality, and silage-fermentation characteristics will need to be rescheduled when alfalfa monocultures are available.
Fall-grown oat studies related to nutrient capture from summer manure/fertilizer applications and studies involving triticale are completed. Data is summarized and published. For studies with spring wheat and spring barley, two years of data collection and analysis are completed. Final year of both studies will be planted in August 2019, with a final harvest scheduled in early November, and a final spring harvest in May/June 2020.
For the winter manure modelling, we established that the existing routines in our SurPhos model work well for simulating P loss in runoff for winter applied manure. One manuscript was published on this topic. However, it appears that the model needs to account for the fact that manure with higher solids content (15-20%) may lose less P in runoff than predicted. We established field trials in Objective 1 to gather data to confirm this and develop new model routines. That work is in progress. Finally, we are currently developing novel routines from our field data in Objective 1 to simulate dissolved NH4 loss in runoff.
We also investigated the use of the Integrated Farm Systems Model (IFSM) to simulate whole-farm nitrogen cycling and use efficiency, and found that the model needs substantial improvement, which was not practical for several reasons. We decided to make a long-term commitment to develop a next-generation, whole-farm dairy simulation model using modern structure, language, and science. We established a collaborative team of researchers from ARS, University of Wisconsin, University of California-Davis, University of Arkansas, and Dairy Management Incorporated Innovation Center to develop the model. This group has been working at model development for almost 2 years. Additional funding sources are being pursued to help fund model development. We have made substantial progress in developing model code for animal, manure management, and crop/soil routines. Group progress is excellent, and the project is continuing very well.
Experiments on measuring pathogen inactivation as related to microbial diversity in groundwater have been completed. Next-Gen sequencing and diversity metrics have been completed. Data is being summarized for publication, and a manuscript is being prepared.
The heifer growth and development experiments related to effects of genomic testing for residual feed intake on nutrient-use efficiency and growth have been completed. One project has been published; others are being summarized and manuscripts prepared for publication. Studies related to effects of pen stocking rate, limit feeding, ionophores, and diet composition on heifer nutrient-use efficiency and growth performance have also been completed and published.
Accomplishments
1. Engagement of bale cutting mechanism only marginally improves silage fermentation. Many round balers now come equipped with cutting mechanisms to reduce forage length; primarily, this facilitates easy incorporation into blended diets, but theoretically could improve silage fermentation. ARS researchers at Marshfield, Wisconsin, and scientists from the University of Wisconsin at Marshfield evaluated the effects of bale moisture and bale-cutter engagement on the nutritive value and fermentation characteristics of alfalfa/orchardgrass silages. Silage fermentation was improved with greater bale moisture, but bale cutting resulted in only modest pH declines of 0.10 to 0.16 pH units over a wide range of initial bale moistures (40 to 70%). Although there may be practical or logistical reasons for bale cutting, such as easing incorporation into blended diets, improvements in silage fermentation do not justify engagement of cutting systems solely for that specific purpose. Furthermore, any premise that cutter engagement could be used as insurance against undesirable secondary (clostridial) fermentations in wet silages is questionable, at best. These results enhance the efficiency of dairy forage production systems by providing producers with information on the cost-effectiveness of bale cutting, which can be used to estimate the net value of new equipment purchases.
2. Timing of triticale harvest for silage requires consideration of competing factors. Dairy producers throughout Wisconsin are increasing the use of winter-annual cereal crops as forages; in part, this emphasis has been to improve environmental stewardship. Questions remain about proper spring harvest timing for these forages. ARS researchers at Marshfield, Wisconsin, and scientists from the University of Wisconsin evaluated the yield, quality, and digestibility of triticale forages harvested over a wide range of growth stages at Marshfield, Wisconsin. In central Wisconsin, a boot-stage harvest will occur about Memorial Day and allows time for a subsequent double-crop of corn. However, this management decision results in a 70% yield reduction compared to a soft-dough-stage harvest. In this study, forage dry matter digestibility and energy density declined with plant development, reaching a minimum at anthesis (flowering), but increased somewhat with grain fill. In contrast, fiber digestibility is independent of grain fill and becomes very poor at advanced growth stages. While harvesting at the soft-dough stage has often been recommended in the past, and will likely maximize yield, this growth stage will not occur in central Wisconsin for triticale until about July 1, thereby precluding a subsequent double-crop of corn. Best management of triticale will require dairy producers to weigh the competing goals of yield facilitated by a soft-dough harvest against the better nutritive characteristics and cropping flexibility provided by boot-stage harvest timing. These results increase the efficiency of dairy production in forage-based systems, as they enable dairy producers to optimize triticale harvest decisions with respect to both crop yield and dairy cow nutrition.
3. Overstocking pregnant dairy heifers at the feedbunk has no effect on growth performance. Various forms of overcrowding are common in heifer-rearing operations. ARS researchers at Marshfield, Wisconsin, and scientists from the University of Wisconsin evaluated the effects of overstocking at the feedbunk (100, 133, 160, or 200% of capacity) on the growth performance of pregnant Holstein dairy heifers. In this study, heifers were overstocked only at the feedbunk, but not with respect to available freestalls or pen area. Overstocking at the feedbunk did not affect nutrient intakes, heifer growth performance, sorting behaviors of dietary components, or overall heifer hygiene under the management system established for this trial. While overstocking had no practical impact on heifer growth performance, it should not be inferred that overstocking at the feedbunk can be practiced blindly without close attention to other critical components of animal welfare. These results help increase dairy production, because they demonstrate that, so long as proper animal welfare is maintained dairy producers can increase heifer numbers at the feedbunk without the concomitant capital costs of renovating or constructing new feeding facilities.
4. Runoff hydrology controls nutrient loss from winter applied dairy manure. Better information is needed for producers and policy makers on the risk of nutrient loss in runoff from dairy manure applied in winter. ARS researchers in Madison, Wisconsin, evaluated nitrogen and phosphorus loss in runoff when liquid dairy manure was applied in either December or January to both tilled and no-till fields. Winter runoff hydrology, specifically the amount of precipitation in snow and rain and how much of that precipitation can infiltrate into soil, controls the loss of manure nutrients in runoff. The time between application and when the runoff happens is not a factor. Therefore, field practices that promote water infiltration, such as fall tillage, and applying liquid manure to unfrozen soils with no snow cover are practices that can consistently help reduce winter manure nutrient loss in runoff. Relying on manure nutrient loss to be less because manure is applied weeks before significant runoff is not dependable. These results help dairy producers conserve soil health and water quality, because they demonstrate that fall tillage and manure application to unfrozen soil reduce nutrient runoff following manure application.
5. Microbial source tracking can determine the level of human fecal pollution in the Menomonee River Basin. In rivers polluted with fecal material the question often asked is to what extent are human sources, like sanitary sewers and septic systems, responsible for the fecal pollution. Scientists studied the Menomonee River Basin in southeastern Wisconsin, where the land use ranges from mostly agriculture upstream to mostly urban downstream. Scientists from USDA-ARS in Marshfield, Wisconsin, quantified the amount of human fecal pollution in the river using measurements of microorganisms that are only found in human gastrointestinal tracts. Using this approach scientists identified the specific watersheds within the river basin that were contributing the most fecal pollution. During rainy periods the amount of fecal pollution added by each watershed varied by a factor of one million. The difference among watershed was not as great during dry periods. The results of this study can be used by water resource managers to understand the land use patterns, environmental factors and watershed properties that lead to human fecal pollution in rivers. These results help policymakers by placing levels of contamination resulting from dairy and other livestock operations in context with those resulting from human contamination, which allows for efficient integrated management of all contaminant sources.
6. Cryptosporidium is frequently detected in groundwater even when surface water has not infiltrated a drinking water well. Cryptosporidium is an intestinal parasite that can cause severe illness and death in people, cattle, and other livestock. Cryptosporidium was responsible for the largest waterborne disease outbreak in United State history, in Milwaukee, Wisconsin, in 1993. In response to the outbreak, federal rules were enacted to protect the nation’s drinking water, but these only apply to public water systems that draw water from a surface water source, like a lake or river. Groundwater sources have been ignored because it is assumed the parasite is too large to move vertically through the soil and reach groundwater. Scientists at USDA-ARS in Marshfield, Wisconsin, sampled wells supplying public water systems in Minnesota and found 40% were positive for Cryptosporidium. The parasite was present even when there was no evidence of surface water entering the well, suggesting it can move from the land surface to groundwater. Cryptosporidum was measured by two methods and both methods gave the same result. From the types of Cryptosporidium identified in the well water it appears the sources were cattle and people. Cryptosporidium is more common in groundwater than generally believed and it occurs at concentrations similar to those found in rivers and lakes. These results inform policymakers that Cryptosporidium, which can be transmitted from livestock to humans through water and causes severe illness in humans, may pose a larger risk than commonly believed for people who obtain their drinking water from groundwater sources, and further drinking water treatment or groundwater protection may be required to mitigate this risk.
7. Automated samplers installed on private wells can measure the variability of microbial contamination in groundwater. Groundwater is often thought to be unchanging, moving slowly underground and staying constant in its chemical and biological composition. This popular perception is untrue, especially for groundwater in the type of aquifer known as fractured bedrock. In the fractures, groundwater can move and change very quickly, behaving more like a river, with changes that happen over the course of hours instead of months. In this type of dynamic aquifer, a one-time sample from a well is not very informative. Scientists at USDA-ARS in Marshfield, Wisconsin, in collaboration with scientists at the U.S. Geological Survey solved this problem by designing the first automated sampler for collecting groundwater samples from private wells. The sampler is controlled remotely by phone and can collect samples continuously over many days. In one private well with the auto-sampler installed, the scientists showed the concentration of some contaminant microorganisms, such as coliform bacteria, can change 100-fold in one day. This new auto-sampler will allow scientists to better characterize the vulnerability of private wells to contamination originating from dairy farms and other livestock facilities, which in turn will enable improved policy and management decisions to conserve water quality for well-owners.
8. Norovirus-contaminated groundwater requires 99.99% virus removal to prevent illness. Contrary to popular perception, groundwater supplies for drinking water are not always pure. Under some conditions disease-causing microorganisms from the fecal wastes of people and livestock can contaminate groundwater and pose a health risk. However, public water systems oftentimes do not disinfect groundwater before consumption, and it is not fully understood what level of disinfection is needed to reduce health risk. Scientists at USDA-ARS in Marshfield, Wisconsin, in collaboration with scientists at the University of Waterloo, Ontario, Canada showed for norovirus, which causes severe gastrointestinal illness and is sometimes found in groundwater, that disinfection would need to remove 99.99% of the virus to reduce illness risk to levels deemed acceptable by U.S. public health officials. In addition, the disinfection estimate is highly variable because the relationship between the number of noroviruses ingested and the risk of illness is highly variable. Nonetheless, the findings lay out an approach that is useful for estimating the benefits of groundwater disinfection, not just for noroviruses, but other waterborne pathogens as well, and the study identified areas in which more research is needed to improve this approach.
9. Mixing manure in anaerobic digesters improves methane production. Anaerobic digesters are used by some livestock farms to process manure and produce methane for energy. Finding the operating conditions for optimal methane production is an active area of research. Using bench-scale digesters scientists at USDA-ARS in Marshfield, Wisconsin, in collaboration with scientists at University of Wisconsin – Madison showed mixing of the manure during digestion increased methane production compared to no mixing. The optimal mixing time was 50%, in which the mixer was turned on for 15 minutes out of every 30 minutes. Mixing at a lower rate, 15 minutes for every 60 minutes, significantly altered the composition of methane-producing bacteria in the digester. Methane was still produced, but less efficiently than at a higher mixing rate. Overall, the increase in methane production with mixing was small and the decision to mix or not in full-scale digesters would need to be weighed against the energy costs for running the mixer. These results allow dairy producers that use anaerobic digesters for manure processing to optimize their digesters with respect to mixing, methane production, and energy costs, thereby improving their operations’ cost-effectiveness and efficiency.
Review Publications
Burch, T.R. 2018. Validation of quantitative microbial risk assessment using epidemiological data from outbreaks of waterborne gastrointestinal disease. Risk Analysis. 39(3), 599–615. https://doi.org/10.1111/risa.13189.
Stock, M.N., Arriaga, F.J., Vadas, P.A., Good, L.W., Karthikeyan, K.G. 2019. Radiative energy absorption of snow after liquid dairy manure application: A field-based, replicated approach. Water Resources Research. 569:51-60.
Williams, K.T., Weigel, K.A., Coblentz, W.K., Esser, N.M., Schlesser, H., Hoffman, P.C., Su, H., Akins, M.S. 2019. Effect of diet energy density and genomic residual feed intake on pre-bred dairy heifer feed efficiency, growth, and manure excretion. Journal of Dairy Science. 102(5):4041-4050. https://doi.org/10.3168/jds.2018-15504.
Gelsinger, S.L., Coblentz, W.K., Zanton, G.I., Ogden, R.K., Akins, M.S. 2019. Ruminal in situ disappearance and whole-tract digestion of starter feeds in calves before, during, and after weaning. Journal of Dairy Science. 102(3):2196-2206. https://doi.org/10.3168/jds.2018-15551.
Coblentz, W.K., Akins, M.S. 2019. Nutritive value and fermentation characteristics of round-baled alfalfa-orchardgrass forages ensiled at various moisture concentrations with or without baler cutting engagement. Applied Animal Behaviour Science. 35(2):135-145. https://doi.org/10.15232/aas.2018-01837.
Coblentz, W.K., Akins, M.S., Kalscheur, K., Brink, G.E., Cavadini, J.S. 2018. Effects of growth stage and growing degree day accumulations on triticale forages: 1) Dry matter yield, nutritive value, and in-vitro dry matter disappearance. Journal of Dairy Science. 101(10):8965-8985. https://doi.org/10.3168/jds.2018-14868.
Coblentz, W.K., Akins, M.S., Kalscheur, K., Brink, G.E., Cavadini, J.S. 2018. Effects of growth stage and growing degree day accumulations on triticale forages: 2) In-vitro disappearance of neutral detergent fiber. Journal of Dairy Science. 101(10):8986-9003. https://doi.org/10.3168/jds.2018-14867.
Coblentz, W.K., Akins, M.S., Esser, N.M., Ogden, R.K., Gelsinger, S.L. 2018. Effects of overstocking at the feedbunk on the growth performance and sorting characteristics of a forage-based diet offered for ad-libitum intake to replacement Holstein dairy heifers. Journal of Dairy Science. 101(9):7930-7941. https://doi.org/10.3168/jds.2018-14543.
Emelko, M.B., Schmidt, P.J., Borchardt, M.A. 2019. Confirming the need for virus disinfection in municipal subsurface drinking water supplies. Water Research. 157(15):356-364. https://doi.org/10.1016/j.watres.2019.03.057.
Esser, N.M., Su, H., Coblentz, W.K., Akins, M.S., Kieke, B.A., Martin, N.P., Borchardt, M.A., Jokela, W.E. 2019. Efficacy of recycled sand or organic solids as bedding sources for lactating cows housed in freestalls. Journal of Dairy Science. 102(7):6682-6698. https://doi.org/10.3168/jds.2018-15851.
Kim, K., Whelan, G., Molina, M., Parmer, R., Wolfe, K., Galvin, M., Duda, P., Zepp, R., Kinzelman, J.L., Kleinheinz, T., Borchardt, M.A. 2018. Using integrated environmental modeling to assess sources of microbial contamination in mixed-use watersheds. Journal of Environmental Quality. 34:1103-1114.
Lenaker, P.L., Corsi, S.R., Olds, H.T., McLellan, S.L., Borchardt, M.A., Dila, D.K., Spencer, S.K., Baldwin, A.K. 2018. Human-associated indicator bacteria and human-specific viruses in surface water: a spatial assessment with implications on fate and transport. Environmental Science and Technology. 52(21):12162-12171. https://doi.org/10.1021/acs.est.8b03481.
McLellan, S.L., Sauer, E.P., Bootsma, M.J., Corsi, S.R., Boehm, A.B., Spencer, S.K., Borchardt, M.A. 2019. Sewage loading and microbial risk in urban waters of the Great Lakes. Elementa: Science of the Anthropocene. 6:46. https://doi.org/10.1525/elementa.301.
Owens, D.W., Hunt, R.J., Firnstahl, A.D., Muldoon, M.A., Borchardt, M.A. 2019. Automated time-series measurement of microbial concentrations in groundwater-derived water supplies. Groundwater. 57(2):329-336. https://doi.org/10.1111/gwat.12822.
Stokdyk, J.P., Spencer, S.K., Anderson, A.C., Walsh, J.F., Firnstahl, A.D., Rezania, L.W., Borchardt, M.A. 2019. Cryptosporidium incidence and surface water influence of groundwater supplying public water systems in Minnesota, USA. Environmental Science and Technology. 53(7):3391-3398. https://doi.org/10.1021/acs.est.8b05446.
Vadas, P.A., Powell, J.M. 2019. Nutrient mass balance and fate in dairy cattle lots with different surface materials. American Society of Agricultural and Biological Engineers. 62(1):131-138. https://doi.org/10.13031/trans.12901.
