Rick Muck *
Ed Prigge *
(304) 293-2631 ex. 4415
Mike Murphy *
Gary W. Fick
Utah State Univ.
Penn State Univ.
Don Horneck *
Oregon State Univ.
Washington State Univ.
Penn State Univ.
* no station report received
Dexel, Hamilton, New Zeland
66 7 858 3787
Project meeting convened at at
H. Tyrell (CSREES
Rep.) gave a report and led a discussion on perspectives from
State reports were given.
presentation was given by Brad Joern on the Nutrient
Management Planner program developed at
State reports were given.
State reports were given.
Heber, gave a brief presentation on research currently
being conducted in air quality at
The business meeting was called to order at Stephen Herbert will be the chair next year. A motion was made, seconded, and passed that Zhengxia Dou be the secretary for next year.
was stated in his absence that Stephen Herbert would rather not host the
meeting next year. David Combs and Richard Muck will host the meeting in
The next rewrite for NE-132 is due in 2004. We should discuss the rewrite at the 2002 meeting.
The NE-132 committee split into three working groups to discuss the following areas:
Each group met for 45 minutes.
The group reconvened at Rabi Mothar reminded the group that each state needs to submit an annual report. Please submit the annual report electronically. Since the annual report and minutes are due in 60 days, please send this information within the next 30 days. The reports should include the objective(s) targeted, and the impact and usefulness of the work being done. The meeting was adjourned at
NE-132 Regional Project Annual Report
Through a collaborating work with R. Kohn (U. Md), Z. Wu (PSU), and K. Knowlton (Virginia Tech), we
investigated the impact of varying dietary P concentrations in lactating cow
diets on the amount as well as chemical forms of P in feces. In three
independent feeding trials, cows were fed diets containing different P concentrations.
The collaborators collected animal performance data along with fecal samples. Fecal
samples were analyzed by Dou at
For the first time, we demonstrate with data from the three independent feeding trials that P added to lactating cow diets through mineral P supplementation is excreted in feces as water soluble forms. This finding has significant environmental implications because water soluble P is associated with potential runoff loss once manure is field-applied. This is particularly important in agricultural systems that rely upon surface applications of manure to pastures or no-till crops, or where bypass flow pathways exist in soils that can accelerate P leaching. Dietary P may be reduced from levels commonly fed on farms, 0.45% or above in many cases, to an apparent adequate range of 0.33 to 0.35% for satisfactory milk production while simultaneously reducing the quantity and susceptibility of P in fecal excretion.
We completed the first phase of a field experiment studying nutrient dynamics in corn (silage), alfalfa, and orchardgrass receiving N- vs. P-based dairy manure applications. This includes a 3-yr cropping cycle with annual nutrient application to corn at planting with chisel tillage, or annual split applications of manure to alfalfa and orchardgrass without incorporation. Nitrate leaching loss was monitored using wick lysimeters installed 95 cm below surface. Soil P accumulation was measured by Mehlich-3 method.
Data indicated that N-based manure applications significantly increased soil test P in all three crops. P accumulation in surface soil (0 to 5 cm) is more dramatic in alfalfa and orchardgrass where manure was surface applied than in corn which involved some incorporation through the minimal tillage. In terms of nitrate leaching loss, Orchardgrass appeared to be better than corn and alfalfa with the lowest mass and concentration of nitrate-N in leachate, although no statistical significance was detected due to large variations. The alfalfa crop, when receiving manure based on its nutrient removal capacity, performed no better than the row crop corn considering the concentration and mass of nitrate leaching loss.
Field leaching experiment with be continued and expanded.
- Starting a second phase with the crops rotated in spring 2002.
- A second type lysimeter (zero-tension pan lysimeters) will be inserted side by side with the existing wick lysimeters for better estimating P leaching loss.
- Runoff collection device will be installed to determine impact of different crops and manure application rates on N and P runoff losses.
Dairy farm P study: from diets to feces to environment.
- An IFAFS project with collaborators at Cornell, PSU, U. Md, Virginia Tech, U. Del.
- To identify an optimal P feeding range for lactating cows by combining research findings with extensive farm data.
- To develop easy-to-use management tools for farm professionals to assess P adequacy vs. overfeeding and to formulate balanced diets.
- To establish quantitative relationships between dietary P, fecal P, and P loss in runoff.
- To provide training and education to veterinarians, nutritionists, producers, nutrient management specialists, and students.
Dou, Z., D. T. Galligan, R.D. Allshouse, J.D. Toth, C.F. Ramberg, and J.D. Ferguson. 2001. Manure Sampling for Nutrient Analysis: Variability and Sampling Efficacy. J. Environ. Qual. 30:1432-1437.
Z., D. T. Galligan, C.F. Ramberg,
Jr., C. Meadows, and J.D. Ferguson. 2001. A survey of dairy farming in
Toth, J.D., Z. Dou, J.D.
Dou, Z., J.D. Toth, D. Galligan,
C. Ramberg, and J.D. Ferguson. 2001. Nutrient
losses to groundwater affected by fertilization and crops. 12th
World Fertilizer Congress. Aug. 3-9,
Dou, Z., K.F. Knowlton, R.A. Kohn, Z. Wu, J.D. Toth,
and J.D. Ferguson. 2001. Phosphorus solubility in manure affected by
diets. Int’l Sym. Addressing Animal Production and Environ. Issues.
representative: Rabi H. Mohtar,
Agricultural and Biological Engineering,
Heather Karsten and Jim Cropper (
Jennifer MacAdam (
Andrew Gillespie, Forestry;
Keith Johnson, Agronomy;
Mike Neary Animal
Science; Jeff Volenec, Agronomy (
Faraj El-Awar (United Nations (formerly
Raghavan Srinivasan and Jimmy Williams (
Xingwen Chen (Tetra Tech, Inc.)
GRASIM Extensions (Nitrogen and Hydrology)
1. Legume has been added to the model to simulate grass-legume mixture. This includes legume growth, nitrogen fixation, and nitrogen transfer from legume to associated grasses. This addition is under validation (Chen, Mohtar, and MacAdam).
2. Sensitivity analysis has been conducted on the model. This helps to identify those most influential parameters and variables in the model, and facilitates the testing of the model (Mohtar and Chen).
3. Water routing and sediment component is developed based on the APEX (Agricultural Policy/Environmental eXtender) model (Chen, Mohtar, and J. Williams).
GRASIM Extensions continued (Agro-forestry and Multiple Species)
1. WWW-based multipaddock version has been developed and validated (Mohtar, Chen, and Zhai) http://http://danpatch.ecn.purdue.edu/~grasim. This new version includes additional grazing schedules.
2. An ArcView interface for GRASIM was developed to address spatial and temporal distribution of input and output data. Evaluation is under way (Zhai and Mohtar).
3. Field testing of GRASIM is being conducted at Martell, W. Lafayette (A. Gillespie, K. Johnson, M. Neary, J. Volenec, R. Mohtar, T. Zhai) and at two additional sites: Penn State (H. Karsten) and the American University of Beirut research farm (F. El-Awar).
4. Growth parameters matrix for a variety of plant species is being constructed using available crop growth data from literature, the three field sites, and FORADS. Parameter estimation methodologies are being used to estimate GRASIM needed parameters since field data collection cost is prohibitive (Jim Cropper, Grazing Lands Technology Institute, USDA).
5. Grazing field trial under agroforestry system is being conducted under a Funds for Rural America grant. Field data on plant growth, animal performance, nutrient cycling, are being collected and being used to quantify the tree impact on forage growth and grazing management (A. Gillespie, K. Johnson, M. Neary, J. Volenec, R. Mohtar, T. Zhai).
Title: Modeling agroforestry pasture system growth
Graduate Student: Tong Zhai
Collaborators: Bernard Engel, Agricultural & Biological Engineering, Purdue University; Andy Gillespie, Forestry & Natural Resources, Purdue University; Xingwen Chen Tetra Tech, Inc.; J. R. Williams, Blackland Research Center; Jennifer MacAdam, Utah State University; Faraj El-Awar, Irrigation/Water Resources Specialist, UNOHCI-Baghdad, P. O. Box: 5859, New York, NY 10163-5859, USA; Heather Karsten, Penn State University.
Goals: To develop a new grazing model that can simulate the growth of mixed species pasture based on the existing grazing simulation model (GRASIM). The model will be expanded to model the agroforestry system and address tree effect in response to solar radiation, rainfall, and soil nutrient competition. The long-term goal is to develop a GIS interface for easy use by resource managers and the public.
Statement of Problem: Using pasture as feed for livestock can be an important part of agricultural economics. Safe rangeland environments require balanced knowledge of pasture growth and its relation to environmental factors. Existing pasture models seldom distinguish the growth of different plant species within a pasture due to the lack of knowledge of growth characteristics in terms of growth parameters and interspecies relation. Another component of this search for sustainable agriculture is the study of agroforestry systems in which the multiple uses of forest cover are recognized, contributing to higher productivity and a safer environment. So far, models dealing with forests require a large number of input data and use many parameters, making their application outside the scope of average users.
Activities: Procedures for estimating growth
parameters for monospecies using numerical
optimization algorithms and field growth data were designed. The resulting
parameter sets are simultaneously checked against parameter ranges derived from
published data. The calibration and validation process, using a growth dataset
Zhai, T., Mohtar, R.H., Chen, X., and Engel, B. Optimization of pasture
system with Grazing Simulation Model (GRASIM). Presented at the 1999 ASAE Annual International Meeting.
Paper No. 99- .
Mohtar, R.H., Zhai, T., and Chen, X. 2000. A world wide web-based grazing simulation model (GRASIM). Computers and Electronics in Agriculture. 29: 243-250.
Mohtar, R.H., and Engel, B. 2001.
Parameter Optimization for GRASIM Plant Growth Submodel. Presented at the 2001
ASAE Annual International Meeting, Paper No. 01-7010. ASAE,
PROJECT TITLE: Environmental and economic impacts of nutrient management on dairy forage systems
PROGRESS OF WORK AND PRINCIPAL ACCOMPLISHMENTS:
Objective 1a. Crop Growth and Conservation Strategies.
Whole farm simulation was used to determine if
adding small grain crops to traditional corn and alfalfa rotations provided
long-term environmental and economic benefits. Small grain cropping strategies
included 1) corn double cropped with barley harvested as cash crop grain and
straw bedding, 2) corn double cropped with barley harvested as feed grain and
straw, 3) corn double cropped with barley harvested as silage, 4) corn double
cropped with rye harvested as silage, and 5) corn replaced with cash crop wheat
and straw bedding. Nitrogen leaching loss over the farm was reduced by 10 kg/ha
when 40% of the corn was double cropped with a small grain, and soil P
accumulation was reduced by 2 kg/ha. Farm net return or profit was increased by
up to $116/cow when double-cropped barley or single-cropped wheat was harvested
as grain and straw, by about $30/cow for double-cropped barley silage, and
$50/cow for double-cropped rye silage. Use of small grain crops on
Double cropping corn after winter rye is becoming
popular on dairy farms in the mid Atlantic region. When harvested as silage in
the spring at an early boot stage of development, rye provides high quality
forage. The crop can also be killed with herbicide and used as a mulch and
green manure, increasing the yield of the following corn crop. A dairy farm in
Weather has had a major influence on crop production in the
Objective 1b. Herd Nutrient Utilization Strategies.
A whole farm analysis was used to evaluate the potential long-term environmental impact and economic benefit of varying the level of concentrate supplementation on seasonal grazing dairies. A representative farm (81 ha) was simulated over 25 years of historical Pennsylvania weather with five levels of daily concentrate supplementation (0, 3, 6 and 9 kg DM/cow in early lactation and a complete total mixed ration fed in confinement) to meet annual milk production levels of 5,000; 6,000; 7,000; 7,700 and 9,000 kg/cow, respectively. The five systems were simulated for three scenarios: 1) milk sold per farm held constant at 625,000 kg, 2) cow numbers held constant at 100 mature cows, and 3) stocking rate set to use all forage produced. Profitability increased as supplementation level increased in the grazing systems, but at a decreasing rate with each successive level of supplementation. Economic risk or year-to-year variation also decreased as concentrate fed increased. Grazing systems showed an economic benefit compared to the confinement system along with a decrease in nitrogen leaching loss. Concentrate supplementation of grazing lactating dairy cows increased profitability with a mixed impact on the nutrient balance of the farm.
Objective 1c. Manure Application and Soil and Water Interactions.
No progress to report.
Objective 1d. Pasture and Grazing.
We determined the accuracy of an electronic capacitance meter, a rising plate meter, and a pasture ruler in measuring forage mass and the cost of measurement inaccuracy. Forage mass was estimated in grazed pastures on farms in PA, MD, and WV in 1998 and 1999 by each method compared with hand-clipped samples. None of these indirect methods were accurate or precise and error levels ranged from 26 to 33% of the mean forage mass. DAFOSYM was used to simulate farm performance and the resulting effects of inaccuracies in estimating pasture forage mass. A representative grazing dairy farm was developed and the costs and returns from low-input and conventional managements were calculated. Different scenarios were then simulated including under or over estimating forage yield on pastures by 10 or 20%. All scenarios simulated resulted in lower returns compared to the optimum farm, with decreases in net return ranging from $8 to $198/ha/yr. Underestimating forage mass resulted in less hay and silage being harvested, more pasture being consumed, and more forage purchased compared to the optimum scenario. The opposite occurred for overestimation. Our results indicate that achieving greater accuracy (to within 10% of actual pasture yield) will improve forage budgeting and increase net returns.
Whole farm simulation was
used to evaluate the long-term effects of cropping and feeding strategies on N
losses from a typical dairy farm on the sandy soils of
Objective 1e. System Integration.
The Catskill and
(robotic) milking systems are just becoming available in the
Objective 2 a. Needs Assessment.
No progress to report.
Objective 2 b. Information.
No progress to report.
Objective 2 c. Tools.
Distribution of the Dairy Forage System Model (DAFOSYM) was maintained on the Internet at http://pswmru.arsup.psu.edu. A new version of the model was released which includes an expanded help system with a complete reference manual of the technical details of the model.
USEFULNESS OF THE RESULTS:
DAFOSYM provides a teaching aid that illustrates the complexity and many interactions among the physical and biological components of the dairy farm. As a research tool, the model is used to study the effects of system changes on the performance, economics, and environmental impact of a farm or to determine a more optimum food production system. DAFOSYM analyses also provide dairy farmers and farm consultants with useful information for strategic planning.
WORK PLANNED FOR NEXT YEAR:
1. Analyze effects of farm size and production level on the economic feasibility of robotic milking.
2. Complete an evaluation of the effect of management strategies on soil phosphorus levels on NY dairy farms.
3. Continue development and verification of a beef component for DAFOSYM to form the new Integrated Farm System Model.
cooperation with Harrison (WA) on the analysis of grass production systems and
nutrient management on western
development and application of DAFOSYM for the evaluation of various grazing
systems used in the northeastern
2. Rotz, C. A., G. W.
Roth, K. J. Soder, and R. R. Schnabel. 2001. Economic
and environmental implications of soybean production and use on
4. Soder, K.J. and
7. Soder, K.J. and
8. Andresen, J.A., G. Alagarswamy, J.T.
NE-132 Regional Project Report:
Department of Animal and Avian Sciences
E-mail: email@example.com URL: http://www.inform.umd.edu/ManureNet
Dairy Herd Management Practices That Impact Nitrogen Utilization Efficiency
Evaluation of Milk Urea Nitrogen Measurements by DHIA Labs
Two studies were conducted on measurement of milk urea nitrogen (MUN) by DHIA laboratories.
The objective of the first study was to
compare the methods that are currently used for analysis of MUN on a routine
basis. Two replicate samples from each bulk tank on 10 different dairy farms
were sent to 14 Dairy Herd Improvement Association (DHIA) labs throughout the
The objectives of the second study were to evaluate models to predict urinary N and expected MUN using older and newer data sets, and to quantify changes that may have occurred in MUN measurements over time. Two data sets were used for model evaluation. Data set 1 was from the spring of 1998 and data set 2 was from the spring of 1999. Similar cows and diets were used in both studies. Using data set 1, the newer model underestimated MUN by an average 3.8 mg/dl, while the older model was accurate. Using data set 2, the older model overestimated MUN by 4.8 mg/dl, but the newer model was accurate. In the period between the two studies, the MUN measured appeared to decrease by an average of 4.0 mg/dl. Using current wet chemistry methods to analyze for MUN, urinary N (mg/dl) can be predicted as .026 times MUN (mg/dl) times body weight (kg). Because of changes in methodology that occurred in the fall of 1998, target MUN concentrations have decreased to 8.5 to 11.5 mg/dl for most dairy herds compared to previous target concentrations of 12 to 16 mg/dl.
Worksheets for Calculating Whole-Farm Nutrient Balances were Released
worksheets to rapidly calculate nutrient balances on livestock farms were
upgraded. This software has been demonstrated and made available for
professionals to use on a farm by farm basis. This software is being used to
quantify typical nutrient flows on farms and to identify critical control
points to reduce nutrient losses from agriculture. The worksheets are available
on the internet at the web address: www.inform.umd.edu/ManureNet/software/
Currently, 141 sites have registered the software, and
these sites are located in 25 states or
Use of milk urea nitrogen can help fine tune dairy cow diets, and when used with a mathematical model we developed, can be used to characterize protein feeding in a region. Better understanding of feeding practices may improve the development of extension programs to target reductions of nutrient losses from agriculture.
The worksheets for calculating nutrient balances have been used to demonstrate the extent of unaccounted for nitrogen and phosphorus on farms. These worksheets have been used to demonstrate the importance of farm management on water quality to individual farmers and extension educators.
additional field study is currently being conducted to introduce the use of
milk urea nitrogen (MUN) to fine tune diets on dairy farms in
A total-collection feeding trial is underway to determine apparent digestibility of phosphorus with two levels of dietary P. Changes in P retention during dry period, early, peak, mid and late lactation across 2 lactations is being measured.
balance worksheets will be used to collect more data on farms in
Kohn, R. A., Kalscheur, and E. Russek-Cohen. In Press. A comparison of models to measure milk urea and urinary N excretion. J. Dairy Sci.
Jonker, J.S., R. A. Kohn, and J. High. In Press. Dairy herd management practices that impact nitrogen utilization efficiency. J. Dairy Sci.
Jonker, J.S., R. A. Kohn, and J. High. In Press. Use of milk urea nitrogen to improve dairy cow diets. J. Dairy Sci.
Jonker J. S. and R. A. Kohn. In Press. Using milk urea nitrogen to evaluate diet formulation and environmental impact on dairy farms. Proceedings of the International Nitrogen Conference.
Dou, Z, K. F Knowlton, R.
A. Kohn, Z. Wu, J. D Toth, and J. D. Ferguson. 2001. Phosphorus
solubility in Manure affected by diets. International Symposium Addressing
Animal Production and Environmental Issues: Proceedings.
Sutton, A.L., T.
J. Applegate, S. Hankins, B. Hill, G. Allee, W.
Greene, R. Kohn, D. Meyer, W.
Powers, and T. van Kempen. 2001. Manipulation of
animal diets to affect manure porduction, coposition and odors: State of the Science. International
Symposium Addressing Animal Production and Environmental Issues: Proceedings.
2001 NE-132 REPORT
DEPARTMENT OF PLANT AND SOIL SCIENCES
Stephen J. Herbert
1. Project report
Nutrient Management Planning Aid
objective has been to develop and implement the use of a decision aid (FarmSoft) for use in “comprehensive” nutrient management
planning. This has been done to meet outreach needs of
first version of FarmSoft was developed by
Nitrogen Sufficiency or Excess in Corn Production
field studies and on farmer fields we have been examining nitrate accumulations
in corn stalks as a measure of N sufficiency or excess. We previously found
that nitrate in corn stalks was significantly affected
by nitrogen/manure management. Application of manure or N fertilizer to corn
following alfalfa in rotation significantly increased nitrate concentrations in
corn stalks by 600%. This trend was has been observed in multiple years. Excess
nitrogen applications, that is more than the crop
needs either in the form of N-fertilizer or manure, may result in nitrate
accumulations rather than an increase in corn yields. Work in
2. Usefulness of the Findings. The introduction of the corn stalk nitrate test provides farmers with another evaluation method to determine whether they are applying sufficient or too much N fertilizer. Further work on improved sampling methods will aid farmer adoption of the corn stalk nitrate test. The decision aid FarmSoft has proven to be comprehensive in terms of meeting most of the needs of comprehensive nutrient management planning. With continued development and review this will become both a useful decision aid for farmers and farm planners and for classroom teaching.
3. Work Planned for Next Year. The studies on sampling methods for corn stalk nitrate test are in progress. Continued development of FarmSoft is planned including enhancements to meet State Standards for comprehensive nutrient management planning.
Liu, X., and S.J. Herbert. 2001. Ecological impacts of cover crops. Journal of Applied Ecology 12(1): 24-29
G., D. Amarasiriwardena, S. Herbert, J. Novak, and B.
Xing. 2000. Effect of cover crop systems on the characteristics of soil humic substances.” in Humic
Substances: Versatile Components of Plants, Soil and Water, The Royal Society
Ding, G., Mao, J., Herbert, S., Amarasiriwardena,
D, and Xing, B., 2001. Spectroscopic evaluation of humin
changes in response to soil managements. In Humic
Substances: Structures, Models and Functions. E.A. Ghabbour
and G. Davis (edit). The Royal Society of Chemistry,
NE-132 Regional Research Project: 2001 Annual Report
Progress of Work and Principal Accomplishments in 2001
Objective 1a. Crop Growth and Conservation Strategies
Based on the results of a simulated grazing and compatibility study of 6 grasses and 24 grass-legume mixtures, a three-year long grazing study consisting of eight binary grass-legume mixtures was established in 2000. Birdsfoot trefoil and white clover comprise the legume component of the eight mixtures. Birdsfoot trefoil has significant potential in the Intermountain West as an alternative to white clover for grazing, as it does not cause bloat and appears to be longer-lived than in warmer, more humid climates. The grass component of the mixtures includes tall fescue, meadow brome, orchardgrass, and perennial ryegrass.
This study will examine the effects of intensive rotational grazing in a dairy system in the Intermountain West. Two grazing treatments (grazing only, and mechanical first cutting followed by grazing) will be examined. Yield and botanical composition of the plots will be measured throughout the growing season. Weather data, including temperature and rainfall amounts, are being collected. Irrigation information is also being collected. Collaborative work on rooting dynamics and irrigation schedule modeling will be conducted.
Objective 1c. Manure Application and Soil and Water Interactions
The fate of nutrients will be examined via leaf tissue samples, soil water samples, and soil analyses. Soil nutrient levels will be determined and fertilization recommendations will be made accordingly. Leaf tissue samples will be collected and analyzed for nutrient composition throughout the growing season. Soil water samples will be collected weekly during the growing season and analyzed for nitrate, ammonium, and orthophosphorus. Spatial variability of the soil test nutrients will be examined in certain plots.
Objective 1d. Pasture and Grazing
Based on previous results, incorporation of legumes into the pastures should improve both the quality and yield. This study will examine the yield and quality of eight grass-legume mixtures under management intensive grazing in the Intermountain West. Previous experience has shown that the percentage of legume tends to increase with time. Persistence and compatibility of the mixtures will be examined.
Usefulness of Findings
This study is just getting underway, but results from this study will determine which mixtures are the most effective under management intensive grazing in the Intermountain West. Field days for producers will be conducted each year. Yield and weather data will be correlated to help improve irrigation scheduling models. Nutrient data being collected will also provide insight into the potential for nutrient leaching under each of the grass-legume mixtures.
Work Planned for 2002
It is anticipated that this project will be continued in years 2002 and 2003. Field days are planned for each year of this project.
Publications in 2001
Karsten, H. D. and J. W. MacAdam. 2000. Effect of drought on growth, carbohydrates, and soil water use by perennial ryegrass, tall fescue, and white clover. Crop Science 41(1):156-166.
Abstracts in 2001
MacAdam, J. W., Mikeski, G. J., and S. Buffler. 2001. Irrigated
grass-legume pasture mixtures: Long-term changes in botanical composition. Agron. Abstracts.
The field evaluation of computer simulation models has included the comparison of field observations (Y) and model predictions of those observations (X). Most often the comparison has been quantified by the use of regression analysis, but it has been unclear what is the appropriate regression: X on Y, Y on X, or principal component regression. By a process of mathematical derivation, and with the help of our colleague G.J.T. Hwang, we were able to show that Y on X is always the procedure to minimize estimated prediction error. Following on previous work that showed that the best estimator of prediction error for a model was the root mean squared deviation (RMSD) for regression, we were able to derive orthogonal components of RMSD related to unequal means (corresponding to a non-zero intercept), non-unity of slope, and lack of correlation between X and Y. These findings add a strong theoretical dimension to the statistical testing of computer models that has not been previously available.
have completed our analysis of data related to accurately measuring pasture
yield by clipping plots with powered shears. Many have observed that some fine
clippings are lost into the stubble and not retrieved with this approach. We
used stubble vacuuming to retrieve all harvested herbage and were able to
separate vacuumed dead material, manure, and soil organic matter from the
clipped herbage lost into the stubble by ashing the
stubble material and then regressing the apparent total organic matter mass
(that included all vacuumed material) on the mass of harvested herbage without
the vacuumed material. The intercept of the regression equaled the average
contamination from vacuuming and the slope of the regression equaled the
average correction for material lost into the stubble. Clippings lost into the stubble in this study amounted to 0.045 Mg/ha of
The mathematical analysis of regression procedures used to evaluate computer simulation models has identified the best method and placed statistical model testing on strong theoretical base. This discovery will strengthen all applications of applied computer simulation modeling.
Testing the accuracy of clipping small plots to estimate pasture yield by vacuuming the stubble showed that the gain in accuracy was small (about 5%) and did not justify the cost of the vacuuming procedure.
The findings on model testing and on measuring pasture yield will be prepared for publication. We will also continue efforts to improve alfalfa quality prediction equations (objective 1a iii) and to develop WWW tools to for the economic analysis of forages given forage quality tests (objective 2b).
Gauch, H.G., and G.W. Fick. 2001. Comparison of simulated and measured values for model evaluation.
In 2001 annual meeting abstracts. American Society of Agronomy,
Joseph H Harrison
Department of Animal Sciences
Seven commercial high producing herds (>28,000 pounds of milk) were visited to collect the following information for the purpose of refining the DAFOSYM model:
· DAFOSYM input parameters (descriptive needed to run a whole farm simulation)
· High Producing Strings – Body weight, wither height, wither to pins length, and DMI
· TMR and feed refusal characteristics – Nasco particle distribution, CP, NDF, ADF, lignin, fat, minerals, and starch
· Manure samples at each point of handling/transformation
· Use of BST and number of times milked/day
Two experiments were conducted to look at sampling method and effect of rBST on milk allantoin concentration and output in milk.
Corn silage was harvested at ~ 30 % DM and stored in either a bunker silo or Ag Bag silo. When fed to lactating cows the bagged silage resulted in 0.6 pounds more milk (not statistically different).
Data collected from commercial farms with high producing cows will be valuable to determine which variables in DAFOSYM need to be adjusted for the model to predict > than 28,000 pounds of milk.
Data collected from the experiments on factors affecting allantoin in milk indicated that sampling method (strip vs composite) had little impact on allantoin concentration. Use of rBSt increased output of allantoin in milk ~ 10 %.
Data collected with bagged vs bunker stored corn silage can serve to help validate the advantage of the bagged system as simulated in DAFOSYM. In addition, it will help producers make more informed decisions about what storage system best meets their goals.
A. Continue to validate/calibrate the animal submodel of DAFOSYM with data collected form high producing herds.
B. Complete and summarize a bunker vs bag storage and feeding study with corn silage at a commercial dairy herd.
C. Complete experiments looking at the factors affecting concentration of allantoin in milk.
Harrison, J H, L Johnson, and B Sanchez, and C A Rotz. 2001. Potassium and phosphorus – Soil/crop/cow interface. Proceedings of Tri-State NW Dairy Shortcourse.
Harrison, J H, L Johnson, and B Sanchez, and C A Rotz. 2001. Nutrient management begins with the nutritionist. Southwest Animal Nutrition and Management Conference.
Schager, W M, J H
Harrison, J H, D Davidson, and D Linder. 2001. Evaluation of the nutritive value of low moisture corn silage stored in Ag Bag vs bunker silos. J Dairy Sci. 84:154 (Suppl 1).
Harrison, J H, D Davidson, and L Johnson. 2001. Evaluation of the nutritive value of processed corn silage harvested at three chop lengths. J Dairy Sci. 84:154 (Suppl 1).
Johnson, L M, J H
Johnson, L M, J H
Johnson, L, and J H
Harrison. 2001. Effects
of mechanical processing on the nutritive value of corn silage and performance
characteristics in lactating dairy cows: 1 Introduction.
Johnson, L, and J H
Harrison. 2001. Effects
of mechanical processing on particle size, pack density, and aerobic stability
of corn silage.
Johnson, L, and J H
Harrison. 2001.Kernal processing:Fermentation
changes in the silo due to maturity and mechanical processing of corn silage.
Johnson, L, and J H
Harrison. 2001. Kernal processing article # 4: Measuring rumen
digestibility of processed corn silage using the macro in situ technique.
Harrison, J H, and L
Johnson. 2001. Management
practices that enhance the nutritive value of ensiled forages. Proceedings of the 10th International Symposium on
Johnson, L, J H Harrison,
W Schager S Chen, C Stockle,
C A Rotz, and F Hoisington. 2001. Evaluation of whole farm economics
and nutrient management practices on
Harrison, J H , and L Johnson. 2001. Processed corn silage – what have we learned? Proc Cornell Nutrition Conference.
Rotz, C A, J H Harrison, and L M Johnson. 2001. Silage processing paybacks look good. Hoard’s Dairyman. P 496, August.
Harrison, J. 2001. Corn silage management in bag and bunker silos. Proc. Pacific Northwest Animal Nutrition Conference.
Johnson, L, and J H
Harrison. 2001. Effects
of mechanical processing on ruminal and total tract digestibility in lactating
Effects of starch degradability and forage particle size on ruminal environment (pH, NH4 and VFA) and production (intake, milk yield and milk composition) was measured in dairy cattle. Cows were fed either cracked dry shelled-corn (low rate of starch degradation) or ground high moisture shelled-corn (fast rate of starch degradation), and forage particle size was altered by feeding coarsely chopped alfalfa silage (mean particle length (MPL) = 13.6 ± 1.7 mm) or the same silage processed through a forage re-cutter prior to feeding (MPL = 3.7 ± 0.4 mm). Treatments were arranged as a 2 x 2 factorial design with starch degradability and forage particle size as main effects. The four diets were formulated to contain 60% concentrate and 40% forage, and contain equal concentrations of CP (20.5%), NSC (47%), total NDF (25% of DM) and NDF from forage (18% of diet DM). Forage particle size did not affect milk yield (44.1 ± 4.3 kg/d) but cows fed HMC tended (P < 0.06) to produce more milk than cows fed dry corn (44.8 vs. 43.1 kg/d, respectively). Neither forage particle length or corn source affected DMI (24.5± 2.1 kg), milk fat (3.6 ± 0.4%) or milk protein (3.1±0.2%). Total ruminal VFA increased as when HMC was fed (P < 0.05) and when forage particle size was reduced (P <0.01). Rumen acetate levels were lower (P <0.05) and propionate levels were elevated when HMC was fed. Forage particle size did not affect acetate but increased ruminal propionate levels. Ruminal pH was measured every minute for 3 days with indwelling electrodes. Feeding HMC decreased mean pH from 5.97 to 5.85 (P< 0.05) and ruminal pH decreased from 6.0 to 5.8 (P< 0.01) when coarse vs. finely chopped alfalfa was fed. There were no interactions between grain fermentability and forage particle size for any of the ruminal or production parameters measured.
Two experiments were conducted to evaluate the effects of corn supplementation, source of corn, and corn particle size on performance and nutrient utilization of lactating dairy cows. In Experiment 1, treatments were 1) direct-cut grass-legume forage without supplement, 2) direct-cut forage plus 10 kg DM of ground dry shelled corn-based concentrate, and 3) direct-cut forage plus 10 kg DM of coarsely ground high moisture ear corn-based concentrate. In Experiment 2, treatments were 1) direct-cut grass-legume forage plus 10 kg DM of ground dry shelled corn-based concentrate, 2) direct-cut forage plus 10 kg DM coarsely ground high moisture ear corn-based concentrate, and 3) direct-cut forage plus 10 kg DM finely ground high moisture ear corn-based concentrate. Both experiments were designed as 3 x 3 Latin squares replicated three times. In Experiment 1, yields of milk and milk protein increased with concentrate supplementation, but were not affected by source of corn. Solids-corrected milk yield tended to increase with grain supplementation. Dry matter intake increased with concentrate supplementation, but was not affected by source of corn or corn particle size. Corn supplements decreased ruminal pH and acetate to propionate ratio and increased ruminal propionate concentration. Grain supplements reduced ruminal ammonia concentration, increased concentration of urine allantoin, and increased the urinary allantoin to creatinine ratio. In the second study, fine grinding of high moisture corn reduced fecal starch plus free glucose levels and tended to increase its apparent digestibility. In experiments, starch plus free glucose intake was higher on the diets with dry corn, but its utilization was not affected by source of corn.
Six pastures (two each of kura clover in mixture with reed canarygrass, tall fescue, or Kentucky bluegrass) have been established at the Arlington Research station and were grazed by dairy cattle throughout the 2001 growing season. Experiment objectives were to measure intake and botanical composition of pastures that differ in sward density, and evaluate the reliability of alkanes as markers to estimate composition of diets consumed by grazing dairy cows. Rumen fistulated cows grazed the three different pasture mixtures. Botanical and chemical composition of forage in the paddocks were measured daily, and samples of rumen contents and feces were collected. Intake is estimated indirectly by measuring fecal output with rare earth markers and by using alkanes as a marker. Botanical composition of the forage consumed is estimated by hand separating rumen contents and by using alkanes as an indirect marker.
Results from the experiment described in (1b) indicate that forage particle size and ruminal starch degradability independently affect rumen pH and animal productivity. These data would indicate that models to predict rumen environment and productivity can focus on the main effects of ruminal starch degradability and effective fiber.
Data from (1d. iii) improves our ability to measure and understand how sward density affects nutrient intake by grazing dairy cattle. Such information provides insight into how to predict forage intake by grazing cattle if pasture availability is known.
1. Complete analysis of an experiment which measured the effects of increasing ruminal starch degradability on ruminal pH, milk yield and milk composition in dairy cows.
2. Continue to measure the effects of pasture availability on intake of dairy cattle. Assess how pasture availability affects botanical composition of forage consumed.
2001: 1 refereed publication, 3 refereed papers submitted (2 in review, one is accepted), 2 abstracts and 9 conference proceedings published.
Riesterer, J. L. , D. J. Undersander, M. D. Casler, D. K.
Combs. 2002. Quality of Forage Stockpiled in
Krause, K. M., D. K. Combs and K. A. Beauchemin. 2002. Effects of forage particle size and
grain fermentability in midlactation
cows. I. Milk production and diet digestibility. J. Dairy Sci.
Krause, K. M., D. K. Combs and K. A. Beauchemin. 2002. Effects of forage particle size and
grain fermentability in midlactation
cows. II. Ruminal pH and chewing behaviour. J. Dairy Sci. 85: (Submitted
Reis, R. B., F. San Emeterio, D. K. Combs, L. D. Satter and H. N. Costa. 2001. Effects of corn particle size and source on performance of lactating cows fed direct-cut grass-legume forage. J. Dairy Science 69:429-441.
Reis, R. B. and D. K. Combs. 2000. Effects of corn processing and supplemental hay on rumen environment and lactation performance of dairy cows grazing grass-legume pasture. J. Dairy Sci. 83: 2529-2538.
Reis, R. B. and D. K. Combs. 2000. Effects of increasing levels of grain supplementation on rumen environment and lactation performace of dairy cows grazing grass legume pasture. J. Dairy Sci. 83: 2888-2898.
Riesterer, J. L. , D. J. Undersander, M. D. Casler and D.
K. Combs. 2000. Forage yield of stockpiled perennial grasses in the upper midwest
Riesterer, J. L. , D. J. Undersander, M. D. Casler and D. K. Combs. 2000. Seasonal yield distribution of cool-season grasses following winter defoliation. Agron. J. 92: 974-980.
Krause, K. M and D. K. Combs. 2001. Effects of sampling frequency and schedule when determining dietary effects on ruminal pH. J. Dairy Sci. 84 (Suppl. 1):78(abstract).
Combs, D. K. and P. Berzaghi. 2001. Comparison of three methods to estimate digestible NDF of forages. J. Dairy Sci. (Suppl.1) : 348(abstract).
Krause, K. M., D. K. Combs and K. A. Beauchemin. 2000. Effect of increasing levels of pure corn starch in the diet of lactating dairy cows on ruminal pH. J. Dairy Sci. 83(Suppl 1):261(abstract).
Combs, D. K. and
P. C. Hoffman. 2001. Improving aerobic stability of silage and high moisture
corn with Lactobacillus buchneri inoculant.
In Proc. Arlington Dairy Day. Dec. 12. Dept. Dairy
Science, Univ. Wisc.
Combs, D. K., D.
J. Undersander, P. Berzaghi
and P. C. Hoffman. 2001. Using digestible NDF to evaluate forage
quality. In proc. Wisconsin Assoc. Professional Agric.
Consultants Ann. Conf. Dec. 4.
Combs, D. K. and
R. D. Shaver. 2001. Forage Utilization by Dairy Cattle: Improving forage
utilization through better testing methods and harvest procedures. In Proc. Babcock Institute Short Course on Dairy Production.
R. R. and D. K. Combs. 2001. Transition Cows: Energy nutrition of the dry
cow just before calving. In Proc. Babcock Institute Short
Course on Dairy Production. June 25-29.
Combs, D. K. 2001. Feeding high producing cows on pasture. In
Proc. Babcock Institute Short Course on Dairy Production. June 25-29.
Combs, D. K. 2001. Managing pastures
for high producing dairy cattle. . In Proc. Babcock Institute
Short Course on Dairy Production. June 25-29.
Combs, D. K. 2001. Supplements for grazing dairy cattle. pp.
66-82 In Proc. Symposium of the Nutrition and
Production of Dairy Cattle. R. B. Reis, S. G. Coelho, and F.
A. P. Vieira, Ed.
Combs, D. K. 2001. Challenges of dairy production under intensive grazing systems.
pp. 39-49 In Proc. Symposium of the Nutrition and Production of Dairy Cattle. R. B. Reis, S. G. Coelho, and F. A. P. Vieira, Ed.
Combs, D. K., and
D. J. Undersander. 2001. Digestible
NDF: What is it and how is it used? In. Proc. Midwest NIR
Consortium Annual Meeting. March 26-26.
Combs, D. K., P. C. Hoffman and D. J. Undersander. 2000. New
approaches to measuring energy and bypass protein in forages by Near Infrared
Spectroscopy (NIRS). pp 89-96. In proc. 4-State Professional
Dairy Management Seminar.
Combs, D. K. 2000. New tests to measure forage digestiblity and bypass protein in forages. In
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