Environmental and Economic Impacts of Nutrient Flows in Dairy Forage
Committee Meeting Minutes
The Netherlands, December 10-14, 2000
Sunday December 10
The group met at 6:30 p.m. at the lobby of WICC
in Wageningen and left for drinks and welcome dinner at restaurant Carré
Monday December 11
The group met at 9:00 a.m.at the Lobby of the WICC
and moved to a 9:30 a.m. meeting with Farm Management Group members. The
meeting theme was farm nutrient management and sustainability organized
by Paul Berentsen. The meeting outline follows:
Program Meeting Farm Management Group, Monday, December 11, 9:30–12:30
Title: Farm nutrient management and sustainability
The structure of agricultural research in the Netherlands and the role of
the Farm Management Group, Prof. Ruud Huirne (head of the Farm Management
A short history of Dutch environmental problems related to agriculture and
consequential policies, Paul Berentsen
||The Dutch Mineral Accounting System and the European Nitrate
Directive; implications for farm performance, Chirstien Onderstein
Economic-environmental modeling of dairy farms, Paul Berentsen
A framework for measuring sustainability in dairy farming, Klaas-Jan van
The group took lunch at de Leeuwenborch and by 1:30
left to visit 'De Marke' experimental farm for nutrient management. The
visit was organized by Frans Aarts. The visit includes an overall presentation
of the experimental farm objectives and history. A brief description of
the farm follows:
De Marke, Experimental Farm for Dairy Farming and the Environment
De Marke, the Dutch Experimental Farm for
Dairy Farming and the Environment, is located on sandy soil. Its goal is
to develop a farming system characterized by optimum efficiency that can
ensure clean soil, clean air and clean water. Since 1993, De Marke
has played a major role in the discussion on efficient dairy farming within
the constraints of stringent environmental targets.
Three institutions operate the farm collectively
in a common interest: efficient dairy farming in a clean environment. These
institutions are the Ministry of Agriculture, Nature Management and Fisheries,
the Ministry of Housing, Physical Planning and the Environment and the
farming industry, who are jointly responsible for the financing.
The main objective of De Marke is to develop
and demonstrate an optimally cost-effective farm setup for dairy farming
with sufficient land area which complies with future-oriented stringent
environmental targets. Further objectives of De Marke are reducing
energy use, reducing the application of crop-protection chemicals, lowering
water consumption, and conserving and developing the natural environment.
Stringent environmental targets have been adopted
which prescribe the maximum environmental loads on soil, air and water.
These stringent environmental limits have been taken from the National
Environmental Policy Plan (NMP), the Multi-Year Crop Protection Plan and
other government papers, which determine how clean the Netherlands is to
be by the beginning of next century.
The following issues require action to be taken:
The acidification of the environment due to ammonia shall be reduced considerably.
The nitrate pollution of groundwater and surface water shall be reduced.
The leaching and runoff of phosphate to groundwater and surface water shall
Denitrification by-products (dinitrogen oxides) contribute to the greenhouse
effect and consequently shall be reduced.
No clear environmental target has been set for potassium as yet, though
target values for potassium contents of groundwater and surface water have
De Marke this results in the following
70 % less ammonia emission than on the average dairy farm in 1980.
The nitrate content shall not exceed 5 mg per litre of groundwater (EU
40 % less emission of dinitrogen oxides than from the average farm in 1990.
Phosphate leaching and runoff shall not exceed 0.15 mg P per litre.
No phosphate accumulation in soils with sufficient or higher phosphate
The group returned to Wageningen by 5:00 pm.
Tuesday December 12
We met at 9:00 at the Plant Research International.
The theme for the meeting was Systems research in dairy farming. The meeting
was organized Herman van Keulen. The meeting included series of talks on
dairy farming impact on the environment and the associated economic problems.
Dr. Keullen discussed some of the group research methodology and system
prototyping. Frans Aarts presented on applications of prototyping to dairy
farming in the Netherlands. He discussed how De Marke links with
the plant research group and discussed the experimental plans and the monitoring
of water, chemical and energy flows. He also discussed the evaluation of
the project and the expert knowledge that is used for continuous adaptation
of the project. Considerable discussion was made on how the De Marke
experience would be beneficial to US conditions.
Al Rotz presented DAFOSYM: A model for farm management
evaluation followed by a presentation on applications of DAFOSYM to nutrient
balances in dairy farming by Joe Harrison.
A general discussion was held on systems research
in dairy farming: comparison of approaches and prospects for comparision.
The group had lunch at de Leeuwenborch and left at
1:00 to Amsterdam accompanied by Anne Houwers. The trip included a canal
boat trip and visit to the historic city. We returned to Wageningen by
Wednesday December 13
The group attended the 9:00 meeting of the Animal
Production Systems Group members. The theme of the meeting was Sustainable
development in practice: methodologies and applications organized by Henk
Udo and Mike Grossman.
WIAS – Animal Production Systems meeting on:
Presentation outlines follow:
Opening – Hank Udo
Assessment of Sustainable Development using
Fuzzy Set Theory, Ton Cornelissen
Are Animal-Friendly Production Systems Sustainable?
Environmental Decision Tools, Imke de Boer
Measuring and Improving Sustainability
in Aquatic Production Systems, Mark Verdegem
10:40-10:55 Greenness Attributes in the Green Piggery
Project, Egbert Kanis
The aim of this meeting was
to exchange information and to explore cooperation possibilities. ‘Wageningen’
participants in Systems Research in Dairy Farming:
Plant Research International – De Marke
Dairy Farming – De Marke
Plant Research International
Plant Research International
Institute Animal Husbandry and Animal Health
The group left at 1:00 from WICC to visit the Dairy
Farm of Wim Veldboom at Zeewolde (participant in praktijkcijfers-project).
The visit included an introduction by a representative from the praktijcijfers-project
and a tour of the farm.
The group returned to Wageningen by 5:00.
Thursday December 14
The group conducted their business meeting at the
Jim Ferguson called the meeting to order at 8:45
a.m. and proceeded with members introduction. There were three new members
at the meeting: Rhonda Miller (Utah State), Zhiguo Wu (Penn State), and
Jeffery Hyde (Penn State).
Minutes of the last year meeting were approved.
They were distributed via email by Jim Ferguson.
Paul Wangsness (NE132 administrative advisor) commented
on the new paper work requirements for reporting. Paul will forward this
information to Rabi Mohtar and Jim Ferguson.
Due to time constraints Ferguson commented that each
station should limit its report to 15 minutes.
Henry Tyrrell (CSREES representative to NE 132) discussed
the new reporting procedure. Details are available on the directors web
site (D. McKinzie). Beside format changes, the annual report is due 60
days after the annual meeting, which is February 11 for NE 132. According
to the new guidelines, the minutes of the meeting should be part of the
report. Additionally, scientist with extension appointments can participate
in regional projects. Henry indicated that NRI got a $13 million hit this
year, and $20 million of its funds were directed to food safety. Three
programs were eliminated including the Ecology Program. The good news is
the IFAFS is back with a $120 million and a new RFP will be out soon. Funds
will be available for multi state integrated applied projects where institutions
can get full overheads. In the new fund, only land grant institutions can
be a lead institution.
As far as other funds, formula funds are maintained
at their previous level, special research funds are increased ($60-$100
million). Section 406 funds also increased especially food safety and water
quality. Funding is also available to support regional water quality centers
in coordination with EPA and USAD.
Henry invited the group to participate in the N-2001
meeting in Washington DC in Oct 14-19, 2001. The meeting is sponsored by
the Ecological Society of America. The conference is funded by USEPA, USDA
is looking at matching the EPA funds.
After some discussion, the group decided to hold next
year's meeting at Purdue University
for two days between the second and third week of November (meeting
will be the chair for next year, Steve Herbert will be the secretary for
the group for next year.
The meeting was adjourned at 11:45.
The group left the WICC at 12:00 for 'de Hoge Veluwe'
accompanied by Marian Jonker, took lunch at pancake restaurant and visited
the Kröller-Müller museum. The group returned to Wageningen by
4:30. At 5:00 the farm managemt group hosted drinks at the Leeuwenborch
(PHLO-ruimte) and farewell dinner later at 7:00 at restaurant de Junushof.
Summary of station reports follow:
NE132 Committee Purdue University Research Report
The Netherlands, December 10, 2000
Rabi H. Mohtar, Agricultural and Biological Engineering, Purdue University
Al Rotz, Heather Karsten and Jim Cropper (Penn State), Jennifer MacAdam
(Utah State), Andrew Gillespie (forestry), Keith Johnson (Agronomy), Mike
Neary (Animal Science), Faraj El-Awar (American University of Beirut),
Raghavan Srinivasan and Jimmy William (Blackland Research Center, TX)
Xingwen Chen and Tong Zhai
GRASIM Extensions (Nitrogen and Hydrology)
The current Nitrogen Stress Factor (NSF) in GRASIM that was developed using
Penn State, University Park, data set is being modified. The previous empirical
NSF formula limits the use of the model to other conditions. With the new
modifications, NSF is only related to Nitrogen status in the soil and is
physically based. This has been tested and documented (Chen and Mohtar).
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 and Mohtar).
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).
Water routing and sediment component is developed based on the APEX (Agricultural
eXtender) model (Chen and Mohtar)
GRASIM Extensions continued (Agro-forestry and Multiple Species)
WWW-based multipaddock version has been developed and validated (Mohtar,
Chen, and Zhai).
Additional grazing schedules have been developed and tested (Zhai and Mohtar)
An ArcView interface for GRASIM was developed to address spatial and temporal
distribution of input and output data. Evaluation is under way (Zhai and
Field testing of GRASIM is being conducted at Martell (W. Lafayette) and
two additional sites, Penn State (H. Karsten) and American University of
Beirut research farm (F. El-Awar).
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
(J. Cropper, Grazing Lands Technology Institute, USDA).
Grazing field trial under agroforestry system is being conducted under
a FRA 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 WWW-based Grazing modeling system and supporting
materials were developed to improve user’s understanding of grazing systems.
Using this tool, users are able to simulate, analyze, and optimize the
impacts of the grazing activity on natural resources and water quality
systems. This results in extended users knowledge and ability to improve
natural resources and water quality protection, as well as improve the
competitiveness of food production in agriculture. The developed case studies
give users practical experience in real life systems modeling and expose
them to environmental issues and water quality protection measures. The
goal is to improve the user's understanding of the interactions between
the various components of the water quality system: soil, water, crop,
animal, chemical, farm management, and their interaction with climatic
uncertainty. On-line documentation is available to help answer questions.
Preliminary evaluation of the educational tool was conducted and the evaluation
results showed that the tool is an effective way to provide education concerning
complex environmental systems. The material is available for your use at
this address: http://pasture.ecn.purdue.edu/~water/teach/src/teach.htm
If you have a specific case study that is not among the list we will be
glad to add that to the list.
NE-132 Annual Report
West Virginia University
Contributors: E. C. Prigge, Div. Anim. &
W. B. Bryan, Div. Of Plant &
E. B. Rayburn, Cooperative Extension
1b. Herd Nutrient Utilization Strategies
Influence of time of supplement feeding and grazing
activity on fiber digestion of cattle.
Prigge and Bryan – Supplementing concentrates to
grazing cattle often results in a depression in fiber digestion which limits
the utilization of this management for increasing the efficiency of production
for lactating cattle. A study was initiated last spring and data collection
was completed this summer. A concentrate supplement was fed to represent
approximately 35% of total estimated DM intake and fed at either 700 or
1900 h. Grazing was allowed for a 12 h (700 to 1900 h) or 24 h period each
day. Sward height on the plots was maintained at either 4 – 8 cm of 10
–14 cm. It is hopeful that the negative associative effect of concentrate
supplementation on fiber digestion could be minimized by allowing time
between the consumption of these two diet components. Variables measured
were: grazing time, forage intake, and digestibility of DM, fiber, and
crude protein. Growth rate and dry matter production of the pastures is
also being monitored.
1d. Pasture and grazing
iii Methods of measuring and predicting pasture yield.
Generalized calibration for pasture plate meter
use in the Northeast.
Rayburn – Research using plate meters to estimate
pasture availability has shown variability of regression estimators due
to season and pasture type; leading to the belief that calibrations of
plate height to clipped sample yield are needed for each pasture and season.
This retrospective study of 33 site years of plate meter research across
four states, seasons of the year, and a range of pasture types found that
forage density (forage mass per cm of height) accounted for the seasonal
effect on plate meter calibrations. Much of the difference between pasture
types was accounted for by pasture sod condition. Pastures, which had open
soil at the base of the plants had lower forage density than stands having
complete site occupation at the ground level. Such pastures occur due to
being recently, being old hay fields, or containing non sod forming species.
Tall fescue sods managed under good fertility and rotational grazing had
higher densities than other mixed grass sods. By cooperatively using standard
calibration-description protocol across a region it may be possible to
provide producers calibrations that provide reliable estimates of pasture
Two referred journals and 2 proceeding articles
NE-132 Regional Research Project: 2000 Annual Report
Joseph H. Harrison - Department of Animal Sciences
Washington State University
I. Progress of Work and Principal Accomplishments
A. Objective1, Section1b. DAFOSYM development and validation.
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
B. Objective 2, Section 2c. Use of milk allantoin to estimate remen
microbial protein flow. An Experiment was conducted to evaluate how
quickly allantoin output in milk changed when a diet change occurred in
lactation dairy cows. Cows were switched from a 40:60 or 60:40 forage to
concentrate diet abruptly. Within 24-48 hours a change in milk allantoin
output could be detected.
C. Objective 1, Section 1a, subsection ii. Corn silage was harvested
at ~40% DM and stored in either a bunker silo or Ag Bag silo. When fed
to lactating cows the bagged silage resulted in 2.75 pounds more 3.5 %
Usefulness of findings
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 on diet changes
and milk allantoin output will help advance milk allantoin as a nutrition
management tool at the field level.
collected with bagged vs bunker stored corn silage can serve to help validate
the advantage of the bagged system as simulated in SAFOSYM. In addition,
it will help producers make more informed decisions about what storage
system best meets their goals.
Work Plan for 2001
Continue to validate/calibrate the animal submodel for DAFOSYM with data
collected from high producing herds.
Complete and summarize a bunker vs bag storage and feeding s tudy with
corn silage at a commercial dairy herd.
Determine the effect of BST administration on the output of allantoin in
referred journals or titles and three continual proceedings.
NE-132 Regional Research Project: 2000 Annual Report
Jennifer MacAdam, Rhonda Miller Utah State University
Progress of Work and Principal Accomplishments in 2000
Objective 1a. Crop Growth and Conservation Strategies
In a recently completed simulated grazing study
of 6 grasses and 24 grass-legume mixtures conducted under irrigation at
Logan, Utah, mixtures yielded approximately twice as much as grasses grown
alone. The presence of a legume increased dry matter and crude protein
through the contribution of the legume, as well as through increased yield
of the grass component. Averaged over three years, the highest-yielding
grasses in the study were tall fescue, meadow brome, and orchardgrass,
which produced 10.1, 7.4 and 6.0 Mg ha –1 y-1, respectively,
when no legume was included. The other grasses were Kentucky bluegrass
and early- and late-maturing varieties of perennial ryegrass, and their
yields when planted alone were 2.5, 3.8, and 3.4 Mg ha-1 y-1,
respectively. Legumes used in the study were alfalfa, birdsfoot trefoil,
white clover, and cicer milkvetch. Mixtures containing white clover were
consistently the highest-yielding, averaging 11.9 Mg ha-1 y-1.
Mixtures with alfalfa averaged 11.4, those with birdsfoot trefoil averaged
11.2, and mixtures with cicer milkvetch were consistently the lowest-yielding,
averaging 9.2 Mg ha-1 y-1.
Usefulness of Findings
Based on the results of the clipping study and the
comparability of specific grasses and legumes, a three-year long grazing
study consisting of eight binary grass legume mixtures was established
in 2000.Birdsfoot trefoil and white clover will be used as the legume component
of mixtures.Birdsfoot trefoil has significant potential in the Intermountain
West as an alternative to white clover for grazing, as it has never caused
bloat in grazing animals and appears to be longer-lived than in warmer,
more humid climates.The grass components of the mixtures will be tall fescue,
meadow brome, orchardgrass, and perennial ryegrass.
Work Planned for 2001
Objective 1a. Crop Growth and Conservation Strategies
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. Collaborative work on rooting dynamics and irrigation
schedule modeling will be conducted.
Objective 1c. Manure Application and Soil and Water Interactions
Soil nutrient levels will be determined and fertilization
recommendations made accordingly. Leaf tissue samples will be collected
and analyzed for nutrient composition throughout the growing season. Soil
water samples will be collected biweekly during the growing season and
analyzed for nitrogen and phosphorus. The fate of soil nutrients will be
examined via leaf tissue samples, soil water samples, and soil analysis.
One referred journal and one abstract published.
NE-132 Regional Project:2000 Annual Report
Progress of Work and Principal Accomplishments
Objective 1 a i. Nutrient uptake and nutritional value of crops.
Yields of corn cilage, alfalfa hay, and
orchardgrass hay have been obtained from the field leaching experiment
that includes various treatments (three crops each receiving Control, Fertilizer,
N-based, and P-based dairy manure applications). Nutrient contents and
removal by the crops are yet to be determined (we’ve just purchased a microwave
digester and will analyze the samples this winter).
Objective 1 c ii. Characterize manure P for potential runoff loss.
Fecal samples collected from three feeding trials were tested in our lab
for P characteristics. The feeding trials were conducted by Kohn at U.
Md, Knowlton at Virginia Tech, and Wu et al. at the Dairy Forage Res. Center,
respectively. We measured water soluble P for all the fecal samples. P
fraction distributions were determined for selected samples.
Dairy and swine manures were amended with four types of power plant by-products
to determine the impact on P solubility and fraction distribution changes
as well as N balance. Incubations with the amendments have been completed;
lab analyses are currently under way.
Objective 1 c iii. Nutrient efficiencies in different cropping systems.
With the field leaching experiment, we collected
samples of manure, crops, soil, and leachate. We have measured some of
the samples and have data on nutrient inputs (applications), P accumulation
in soils as a result of the treatments. Determination of nutrient outputs
in leachate and crops will be completed this winter. Upon the completion
of the laboratory analysis, we will be able to compare the nutrient efficiencies
of three crops (corn, alfalfa, and orchardgrass) with N- vs. P-based manure
Objective2. Develop research-based information…educational materials in
support of… agricultural consultants, and producers to strengthen the U.S.
Efforts are being made to integrate animal
agriculture nutrient management with veterinary education and outreach
Classroom lectures and field trips offered in two courses.
Summer fellowship program was offered to two vet students, working on manure
and bedding amendments for reduced nutrient losses and computer modeling
of nutrient cycling on animal farms.
A 2+ day workshop at the PVMA annual meeting specifically on the issures
of animal farm nutrient management.
Serial seminars at the Penn Conference (Veterinary Practitioners) on nutrient
management, the environment, regulations, management options, veterinarians’
roles and opportunities.
Usefulness of Findings
P accumulation in soils – The N-based manure treatment resulted in increased
soil test P accumulation after 2-yr’s applications compared to other treatments
(Control, Fertilizer, or P-based manure rate). Soil test P (Mehlich-3 method)
in 0 to 20 cm soil profile increased 18% in alfalfa, 34% in corn, and 8%
in orchardgrass between Fall 1998 and Spring 2000 for plots receiving N-based
manure. Surface soil P enhancement was not found in the other treatments.
Nutrients in leachate – nitrate-N concentrations averaged above EPA drinking
water standard (10 mg/L) in corn and alfalfa receiving fertilizer or manure,
but below the standard in orchardgrass regardless of nutrient treatments.
P concentrations in leachate continue to be a concern, ranging from .05
to .13 mg/L (EPA critical values associated with accelerated eutrophication
are 0.05 mg DP, 0.10 mg TP L-1).
Fecal P fractionation from the feeding trials – P analysis of fecal samples
from all three feeding trials indicated a similar pattern: Increasing dietary
P levels resulted in not only higher excretion of total P in feces but
more importantly an increased proportion of water soluble P fraction in
Work Plan for 2001
Continue the field leaching experiment. Sample collection with continue
with soils (nitrate and P), leachate, and crops. Crop rotation will be
implemented at the end of Yr 2001 growing season.
Complete nutrient analysis of crop samples. Perform annual and rotational
nutrient balance per treatment per crop.
Continue to explore fecal P characteristics as affected by dietary P levels
and feed ingredients (in collaboration with Kohn, Wu, Knowlton).
(If funding available) we attempt to:
Install runoff collection devices in the lysimeter field so that both leaching
and runoff losses of nutrients can be measured under the treatment scenarios,
Insert pan lysimeters for more accurate determination of P leaching loss,
Conduct lab trials to evaluate wick material for P retention potential.
Four referred journal articles, one abstract, and
1 proceeding published.
Title: An assessment of ammonia emissions from dairy facilities
Authors: James D. Ferguson, Zhengxia Dou,
Institution: University of Pennsylvania
School of Veterinary Medicine
Center for Animal Health and Productivity
382 West Street Road
Kennett Square, PA 19348
A survey of 747 dairy farms in Pennsylvania was used
to construct demographics for the average Holstein dairy farm. The average
Holstein dairy farm was composed of 69 lactating cows, 11 nonlactating,
pregnant cows, and 52 nonlactating, nonporous (heifers) animals. Milk production
averaged 27.4 kg (60.2 lb). Crop acres averaged 71.6 hectares. Milk production,
crop acres and type and average county yields, and herd animal groups were
used to construct a typical feeding program for these farms. Typical rations
were constructed for 6 feeding groups (3 milk production groups, 1 nonlactating
group, 2 heifer groups) to meet milk production, pregnancy and growth requirements.
Rations were constructed based on three forage qualities (excellent, average,
and poor) typically observed on PA dairy farms. Data for animal description
(milk production, body weight, growth, and pregnancy status) and ration
components and amounts consumed for each animal group were input into the
excretion model of the Dairy Nutrient Planner computer program (DNP). Excretion
of fecal N, urinary N, total P and K, and fecal dry matter were for each
animal group was output and used to assess potential volatile losses of
N. Work at the Marshak Dairy, New Bolton Center, indicates the majority
of urinary N is lost as ammonia rapidly from dairy facilities. Based on
this observation, the losses of N as ammonia were estimated to be 4.63,
4.62, and 4.28 metric tons per year for the farms with excellent, average,
and poor quality forages.
Volatile losses of N may most reduced by controlling
levels of urea in urine. Urinary N may be reduced through dietary manipulation
of protein and carbohydrate sources. Conversion of urea to ammonia may
be reduced by altering the pH of barn floors and gutters. Entrapment of
ammonia may be accomplished by acidification of manure slurry.
PROGRESS REPORT – REGIONA RESEARCH PROJECT NE-132
Pasture Systems and Watershed Management Research Unit
USDA/Agricultural Research Service
University Park, PA
TITLE: Environmental and economic impacts of nutrient management on
dairy forage systems
LEADERS: C. Alan Rotz and Matt A. Sanderson
OF WORK AND PRINCIPAL ACCOMPLISHMENTS:
Objective 1a. Crop Growth and Conservation Strategies.
The Dairy Forage System Model (DAFOSYM) was used
to evaluate the economic and environmental impacts of adding 50 acres of
corn, barley, soybeans, or pasture to a 150 acre, 100-cow dairy farm in
Wisconsin. The greatest benefit came from adding rotationally grazed pasture
where annual farm profit increased about $20,000. Volatile nitrogen (N)
loss from the farm increased 10%, but N leaching loss per land unit decreased
50%. Adding a bunker silo for more corn silage and 50 acres of corn, barley
for feed grain and straw bedding, or soybeans for roasting and feeding
all had similar impacts. Volatile N loss and N leaching loss per land unit
were reduced about 15% and 20%, respectively. Annual farm profit was increased
about $10,000 with more corn or soybeans and $14,000 with barley. All crop
options reduced soil phosphorus (P) accumulation by 9 lb/acre/year.
A whole farm analysis was conducted to determine the
potential long-term economic benefit and environmental impact of growing
and feeding soybeans as a protein feed supplement. Representative dairy
farms were simulated with alternative production strategies for 25 years
of Pennsylvania weather. Production of soybeans as a cash crop increased
annual farm net return by up to $55/cow when ample cropland was available
to produce most of the feed requirement of the herd. With a more restricted
land base, there was less economic benefit to shifting land from corn or
alfalfa production to soybeans. When the soybeans were fed in a raw or
roasted form, most of this economic benefit was offset giving an increase
in annual net return of less than $15/cow. There was also little environmental
benefit (reduced N loss or soil P accumulation) for growing soybeans as
a cash crop or feed on dairy farms. In general, the current trend toward
producing and feeding soybeans on dairy farms does not appear to provide
substantial long-term economic benefit to the producer nor reduce the potential
impact of the farm on it’s environment. However, under specific farming
practices such as inefficient feeding of protein supplements or the production
and feeding of high corn silage rations, economic benefit of up to $100/cow
were obtained through soybean production and feeding.
Objective 1b. Herd Nutrient Utilization Strategies.
A representative farm with 400 Holstein cows (producing
11,000 kg/cow/yr) and their replacements on 300 ha of silt loam soil was
simulated over 25 yr of Pennsylvania weather. Multiple simulations predicted
the effects of animal density, herd production, and feeding strategy on
N loss, P balance, and farm profit. Reducing the land area to 200 ha nearly
doubled N losses and increased soil P accumulation by 15 kg/ha/yr with
little change in farm profit. At 400 ha, the farm was near a long-term
P balance with an N fertilizer requirement of 50 kg/ha. A 10% increase
in herd production through the use of BST provided a small increase in
N loss and soil P level; whereas, a 25% drop in production reduced N losses
10% and P buildup by 3.6 kg/ha/yr. Changing the breed to Jerseys while
increasing animal numbers to maintain the same sale of fat corrected milk
increased N losses 45% with a small increase (1.8 kg/ha/yr) in excess P.
Compared to soybean meal as the sole protein feed, including a low RDP
feed in rations reduced N volatile loss 35%, reduced N leaching loss 20%,
and increased production and profit with little effect on soil P. Increasing
the feeding of P to 20% above the NRC recommended level (common practice)
increased the long-term buildup of soil P by 8 kg/ha/yr; whereas, a 20%
reduction provided concurrent farm balances of both N and P. Shifting from
low forage rations to maximum use of forage increased the purchase of alfalfa
hay and reduced grain imports, which increased N losses slightly with little
effect on P balance and farm profit. Changing from a corn and alfalfa rotation
to all corn reduced N volatilization loss 14% and increased leaching loss
22% with little effect on soil P.
Objective 1c. Manure Application and Soil and Water Interactions.
No Progress to report.
Objective 1d. Pasture and Grazing.
DAFOSYM was used to simulate the economic effects
of inaccuracies in estimating forage production on pasture. A representative
grazing dairy farm was developed and the costs and return from “optimum”
management were calculated. Different scenarios were then simulated including
under or over estimating forage yield on pastures by 10 or 20%, under estimating
yield by 10% in spring and overestimating by 10% in summer, and vice versa.
All of the scenarios simulated resulted in lower returns compared to the
optimum farm. Differences in net return compared to the optimum farm ranged
from -$3 to -$80/acre/year. Underestimating pasture production resulted
in less hay and silage being produced, more pasture being consumes, and
more forage purchased compared to the optimum scenario. The opposite occurred
for overestimation of pasture. Thus, achieving greater accuracy (to within
10% of actual pasture yield) in estimating pasture yields improves forage
budgeting and increases farm net return.
Objective 1 e. System Integration.
Three grazing options were compared to a traditional
corn and alfalfa based confinement feeding system for a Michigan dairy
farm. To maintain a long-term phosphorus balance, 85 high producing cows
and replacements were allowed on the 200-acre base farm. Converting 50
acres of alfalfa to permanent grass pasture increased the average annual
net return by $41 /acre. Converting the entire land base to grass with
more extensive use of grazing and a 10% reduction in milk production increased
the net return by $68/acre and reduced nitrogen leaching loss by 50%. A
low input system using all grass pasture, out wintering of animals, a spring
calving cycle, and relatively low milk production allowed a phosphorus
balance with about 50% more animals on the farm. This low input approach
reduced animal facility, feed production, and manure handling costs and
increased milk sales providing a $190/acre increase in the average annual
A representative 200-acre Pennsylvania dairy farm
using management-intensive grazing with spring calving was simulated over
25 years of weather to determine the effects of herd size and milk production
level on profitability and P loading. Increasing herd size resulted in
dramatic increases in P loading, while increases in per cow milk production
levels increased P loading only moderately. To maintain an annual P balance,
the more profitable management strategy was the smaller herd size (100
cows) with greater per cow milk production (17,000 lb). This was largely
due to the decreasing proportion of nutrient intake used for animal maintenance
as milk production increased. Therefore, there is economic and environmental
efficiency in feeding cows grain for extra production while fully utilizing
Whole-farm simulation was used to estimate changes
in economics and nutrient balances caused by management changes for farms
in Denmark and the USA. The Danish farm at the northwest coast of Jutland
has 73 ha of crop and pastureland, 54 milking cows producing 8571 L milk/year,
and 60 young stock. The US farm located in central Pennsylvania has 100
milking cows producing 8790 L milk/hear, 85 young stock, and 81 ha of crop
and pasture land. At the Danish farm, we simulated the effect of reducing
the protein degradability of the protein supplement. Reducing the protein
degradability did not affect net return but reduced N-volatilization by
19% and N-leaching by 8% compared to the base farm. Maintaining farm milk
productivity by milking more cows of lower productivity resulted in negative
economic returns and increased N-losses. The US scenario was changed from
a year-round confinement operation to a system where cows were grazed from
April to October. This change resulted in a 4% increase in net return and
an 18% decrease in N-leaching loss.
Objective 2 a. Needs Assessment.
No progress to report
Objective 2 b. Information.
The planning and selection of equipment for harvest
and handling of forage crops can greatly impact the performance and profitability
of a farm. The type and size of equipment used affects the harvested yield
and nutritive value of the forage crop as well as production costs. Through
interactions with other parts of the farm, these effects can impact market
value of the forage, animal intake and performance, delays in other farm
operations, other production costs, and ultimately farm profit. Models
were used to determine the range in harvest capacity, labor requirement
and production cost of the major sizes and types of forage harvest systems.
This information can improve the planning and selection of equipment to
help assure a profitable operation that meets current and future goals
of the farm.
Objective 2 c. Tools.
Distribution of the Dairy Forage System Model was
maintained on the Internet at http://pswmru.arsup.psu.edu
Development of a new integrated Farm System Model was begun which expands
DAFOSYM to include crop, dairy and beef farm options.
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:
An analysis of the whole-farm economic and environmental impacts of small
grain crops on northeast dairy farms will be completed in cooperation with
faculty of Penn State University (PA).
A comprehensive analysis of management effects on phosphorus levels will
be conducted for representative dairy farms.
Work will continue on the development and verification of a beef component
for DAFOSYM forming the new Integrated Farm System Model.
Cooperation will continue with Harrison (WA) on the analysis of grass production
systems and nutrient management on western Washington dairy farms.
Further development and application of DAFOSYM is planned for the evaluation
of various grazing systems used in the northeastern U.S.
Two journals articles and six continuing proceedings
PROGRESS REPORT – REGIOINAL RESEARCH PROJECT NE-132 (Rev.)
MICHIGAN STATE UNIVERSITY
December 11-15, 2000
TITLE: Environmental and economic impacts of nutrient management on
dairy forage systems.
LEADER: M. S. Allen
R. Longuski, D. Main, S. Mooney, M. Oba, J. Voelker, Y. Ying.
Objective 1b. Herd nutrient utilization strategies.
Effects of conservation method
of corn grain and dietary starch content on DMI and productivity of lactating
dairy cows were evaluated. Eight ruminally and duodenally cannulated Holstein
cows (55+15.9 DIM; mean+SD) were used in a duplicated 4 x
4 Latin square design with a 2 x 2 factorial arrangement of treatments.
Experimental diets contained either ground high moisture corn (HM) or dry
ground corn (DC) at two dietary starch contents (32 vs. 21%). Mean particle
size and DM content of corn grain were 1863 um and 63.2 %, and 885 um and
87.7% for HM and DG, respectively. All diets were formulated for 18% CP,
and sources of dietary protein were alfalfa silage (50% of forage at DM
basis), SBM, distillers grain, and blood meal.
Amount on OM truly fermented
in the rumen varied from 7.7 (DG at 21% dietary starch) to 11.3 kg/d (HM
at 32% dietary starch) among treatments. The HM treatment decreased DMI
compared to DG in high starch diets (20.8 vs. 22.5 kg/d), while there was
no difference in low starch diets (19.7 vs. 19.6 kg/d). This reduction
in DMI is attributed to smaller meal size for HM compared to DG in high
starch diets (1.9 vs. 2.3 kg of DM for high starch diets; 2.1 vs. 2.0 kg
of DM for low starch diets). Faster starch fermentation for HM in high
starch diets might result in satiety sooner. Milk yield was greater for
cows fed high starch diets compared to cows fed low starch diets (38.6
vs. 33.9 kg/d) regardless of corn grain treatment. HM decreased 3.5% FCM
compared to DG in high starch diets (35.7 vs. 38.7 kg/d), while there was
no difference in low starch diets (35.7 vs. 35.4 kg/d). This is because
of lower milk fat content for cows fed HM in high starch diets (3.05 vs.
3.59% for high starch diets; 3.95 vs. 3.73% for low starch diets). Milk
protein content was lower for HM in high starch diets (2.98 vs. 3.02%)
but higher for HM compared to DG in low starch diets (2.94 vs. 2.87%).
Reducing ruminal starch fermentation by substituting DG for HM can increase
productivity of lactating cows fed high starch diets.
True starch digestibility in
the rumen was higher for HM compared to DG, and the difference was greater
for high starch diets (71.1 vs. 46.9%) compared to low starch diets (58.5
vs. 45.9%). This interaction is attributed to a greater increase in digestion
rate of starch for HM compared to DG in high starch diets (28.2 vs. 14.6%/h)
compared to low starch diets (16.8 vs. 12.2 %/h). This suggests that ruminal
starch digestion is limited by enzyme activities as well as substrate availability;
ruminal contents of cows fed low starch diets may have insufficient amylolytic
activity for maximal starch digestion when readily fermentable starch is
available. Starch digestibility in the total t tract was not affected by
corn grain treatment because of compensatory digestion post-ruminally.
Efficiency of microbial nitrogen
production (MNE) was lower for HM treatment compared to DG (39.7 vs. 48.4
g/kg of truly ruminally fermented OM), but was not affected by dietary
starch content. Within the data set of cow-period means, MNE was not related
to daily mean ruminal pH or minimum ruminal pH (recorded every 5 sec. For
4 d per period). MNE was negatively correlated with rate of starch digestion
(r=-0.55), which implies that energy spilling partially explains lower
MNE for HM treatment. However, energy spilling does not appear to be from
lack of ammonia because there was no relationship between MNE and ruminal
ammonia concentration. Maximum rate for microbial protein synthesis independent
from substrate availability might limit microbial N production. In addition,
MNE was positively correlated with rate of passage for OM, starch, and
NDF (r=0.77, 0.75, and 0.63, respectively). Rapid passage rate may decrease
microbial turnover in the rumen, resulting in increased MNE.
Post-ruminal digestibility for
non-ammonia-nitrogen was greater for HM compared to DG, and the increase
was greater for high starch diets (74.3 vs. 68.7%) compared to low starch
diets (71.2 vs. 70.6%). This might be attributed to greater microbial N
excretion as feces due to enhanced starch digestion in the large intestine
for cows fed DG compared to cows fed HM or to more resistant protein for
DG compared to HM.
USEFULNESS OF THE RESULTS:
The results of this work will
provide useful information to allow nutritionists to prepare more optimal
diets for dairy cattle. It will also be used to refine the animal model
of DAFOSYM which provides dairy farmers and farm consultants with useful
information for strategic planning.
WORK PLANNED FOR NEXT YEAR:
Conduct study to evaluate
effects of substitution of beet pulp for high moisture corn in low forage
NDF diets on ruminal digestion kinetics, ruminal pH, microbial efficiency,
dry matter intake and productivity of lactating cows.
Conduct a series of experiments
to evaluate effects of propionate on feed intake.
Conduct a series of experiments
to evaluate effects of sodium, potassium, and systemic acid-base balance
on feeding and chewing behavior, ruminal pH, milk yield, and milk components
of lactating cows.
Nine journal articles were
NE-132 2000 Illinois Station Report – M. R. Murphy
Within-day feeding behavior of lactating cows was studied to complement
previous research on factors affecting peripartum changes in feed intake
and its day-to-day variation.
Six weeks of data fro 40 lactating cows were gathered as part of an experiment
by Zadok Shabi at the Volcani Center in Israel.
A real-time control system recorded the times that individual cows entered
and exited the feeder and the feed consumption for that visit.
Milk production and composition were also measured during the trial.
The binormal distribution of feeding activity explained an average of 91.5%
of the within-day variation.
Feeding activity peaked at 8:14 (sunrise 5:08) and 16:34 (sunset 18:18)
61% of the total intake was associated with the first peak and 39% with
The broader the second peak, the more total feed was consumed (r=0.38,
NE-132 Annual Report, 2000
USDA, ARS, U.S. Dairy Forage Research Center
R. E. Muck, J. M. Powell
Progress of the Work and Principal Accomplishments:
Objective 1a. Crop Growth and Conservation Strategies.
We continued to investigate various combinations
of modified atmosphere (MA) and normal anaerobic storage for improving
the preservation of true protein in alfalfa silage. Difficulties have been
encountered in developing an MA system that works consistently. Work was
initiated to study densities and losses in pressed bag silages.
We determined the variability of soil test P (STP)
levels on dairy farm fields and response of alfalfa and corn to STP by
sampling fields on dairy farms in MN and WI during 1999. STP levels varied
widely, especially within fields as the mean STP level increased. STP did
not affect corn yield and P uptake and 1st cut alfalfa yeid,
but 2nd and 3rd cut alfalfa yields improved as STP
increased from low to optimum. Tissue P concentration in 2nd
and 3rd alfalfa cuttings did not respond to STP but increased
with STP in 1st cut alfalfa. Alfalfa K increased with soil test
P and K; STP and STK were highly correlated.
Objective 1c. Manure Application and Soil and Water Interaction.
Dairy urine (UN), feces (FN) and the undigested
fiber component in feces (FUFN) were each enriched in 15N and
applied to 16 soils.Inorganic N accumulated during the 24-week incubation
period with UN, but FN and especially FUFN appeared to immobilize soil
15N and difference methods gave different estimates of
FN and FUFN mineralization. Estimates of UN mineralization were similar
using both methods.
In a separate trial, we found that the land application
of manure derived from dairy cows fed a high P diet results in runoff dramatically
higher in soluble P than from plots amended with manure from cows fed a
P adequate diet.
Usefulness of the Results
Forages showed little yield response to high soil test phosphorus and potassium,
but high P-testing soils on dairy farms may produce forage that contains
too much K to be safely fed. Fields with high STP are much more variable
in STP level and need more sampling to adequately estimate mean STP.
Most dairy producers feed excessive P, dramatically increasing the cropland
needed for recycling manure and affecting the number of cows a farm can
keep or the duration a farm can operate before excessive levels of soil
test P occur. According to new USDA-NRCS guidelines, manure should not
be applied to cropland having excessive levels of soil test P. Our work
also suggests greater potential environmental impact from P in runoff on
farms where excessive P is fed.
Work Planned for Next Year
Work will continue to develop practical modified atmospheric techniques
for preserving protein in alfalfa during ensiling. The study of density
and losses in bag silos will be completed.
Distributed effort. We recently received
funding for an IFAFS project entitled “Enhanced Integrated Nutrient Management
on Dairy Farms”. This project seeks to (1) develop dairy diets that support
high levels of milk production but produce manure N and P that is less
susceptible to environmental losses, (2) identify how herd management and
manure handling, storage and application practices affect nutrient cycles,
(3) evaluate the effectiveness of conventional and alternative cropping
systems for providing quality feed to the dairy herd and recycling manure
nutrients, (4) develop tools for individual farmers, their extension educators
and private consultants that assess where the greatest nutrient losses
occur based on current farm management practices, and (5) develop curriculum
for use in university education on nutrient cycling and nutrient management
planning using dairy systems as the model. This project will contribute
to Objectives 1a, 1b, 1c, 2b and 2c of the NE-132 project.
Three journal articles, three abstracts, and two
proceedings were published.
NE-132 Regional Project Report: December 11, 2000
Richard A. Kohn
Department of Animal and Avian Sciences
University of Maryland
College Park, MD 20741
Progress of Work and Principal Accomplishments
Evaluation of Protein Recommendations for Lactating Dairy Cows:
The objective of this study was to evaluate the
National Research Council’s recommendations for feeding levels of rumen
undegraded protein (RUP) for cows fed a one-group total mixed ration. Sixty
Holstein cows were paired by parity (1 to 6) and days in milk (23 to 315)
and were randomly assigned to one of two treatment sequences. Diets contained
alfalfa silage (30% diet DM) and corn silage (26% diet DM), and were isonitrogenous
(16% CP) and isocaloric (1.71 mcal/kg). Soybean meal, protected soybean
meal (Soy Best®), and urea were used to make ration protein
fractions that were predicted to be 35% or 29% RUP. The 35% RUP diet was
formulated to provide 98% and 105% of the average requirement for RUP and
rumen degraded protein (RDP) respectively. The ration containing 29% RUP
provided 79% and 117% of average required RUP and RDP respectively. All
cows were group fed and high RUP diet during a 2-week pre-treatment period,
and then were fed one ration for 4 weeks followed by the other for 4 weeks
according to their assigned treatment sequence. Data were collected in
the last week of each period. Mean milk production, milk fat, and milk
protein were 32.6 kg/d, 4.35%, and 3.36% respectively with no treatment
differences. Treatment response was not affected by degree of predicted
RUP deficiency. The degree of expected deficiency was diminished for higher
producing cows and increased for lower producing cows because the cows
are the feed to meet their energy requirements. Thus lower producing cows
ate less than predicted by NRC and higher producing cows ate more. National
Research Council requirements for RUP may be too high for cows fed diets
similar in energy to a one-group total mixed ration. Alternatively, estimates
of RUP content of feedstuffs may be low.
Worksheets for Calculating Whole-Farm Nutrient Balances were Released
Excel worksheets were developed to rapidly calculate
nutrient balances on livestock farms. This software has been demonstrated
and made available for professionals to use on a farm-by-farm basis. It
has also served as a workshop activity to demonstrate typical nutrient
flows and control points on farms. This software is now being used to quantify
typical nutrient flows on farms and to identify critical control points
to reduce nutrient losses from agriculture. Recently the worksheets were
made available on the internet at the web address: www.iinform.umd.edu/ManureNet/software/
The worksheets have been distributed to 25 locations in 11 states and 4
Usefulness of Findings
Current recommendations for protein feeding requirements
are based on experiments conducted on individual cows. However, most farmers
feed their cows in groups. Previous theoretical research suggested that
using current recommendations for lead factors, protein may be overfed
for grouped cows. The current study confirms that requirements may be lower
for grouped cattle do to the interaction of energy and protein.
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
Work Plans for 2000-2001
A field study is currently being conducted to introduce
the use of milk urea nitrogen (MUN) to fine tune diets on dairy farms in
Maryland. A comparison of laboratories for analyzing MUN is currently being
A total-collection feeding trial is underway to
determine apparent digestibililty 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.
Farm balance worksheets will be used to collect more
data on farms in Maryland and these results will be summarized.
Six referred publications, six proceedings, seven
popular/extension articles, and five abstracts were published.
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