NE-132 Meeting Minutes

November 5 and 6, 2001

Purdue University

West Lafayette, IN

Monday Morning

In attendance:

Name	Address	Phone	E-mail
Stephen Herbert	U.Mass Amherst	(413) 545-2250	sherbert@pssci.umass.edu
Rick Kohn	Univ. MD, College Park	(301) 405-4583	rkohn@wam.umd.edu
David Combs	Univ. Wisconsin	(608) 263-4844	dkcombs@facstaff.wisc.edu
Rick Muck *	USDA, ARS, Madison, WI	(608) 264-5245	remuck@facstaff.wisc.edu
Ed Prigge *	West Virginia Univ.	(304) 293-2631 ex. 4415	eprigge@wvu.edu
Mike Murphy *	Univ. of Illinois	(217) 333-0093	mrmurphy@uiuc.edu
Zhengxia Dou	Univ. of Pennsylvania	(610) 444-5800	dou@cahp2.nbc.upenn.edu
Henry Tyrrell	USDA/CSREES	(202) 401-5611	ktyrrell@veeusda.gov
Gary W. Fick	Cornell Univ.	(607) 255-1704	gwf2@cornell.edu
Rhonda Miller	Utah State Univ.	(435) 797-3772	rlmiller@cc.usu.edu
Paul Wangsness	Penn State Univ.	(814) 865-2541	pjw2@psu.edu
Don Horneck *	Oregon State Univ.	(541) 567-8321	Don.Horneck@orst.edu
Joe Harrison	Washington State Univ.	(253) 445-4638	harrison@puyallup.wsu.edu
Al Rotz	USDA/ARS, Univ. Park	(814) 865-2049	alrotz@psu.edu
Dennis Buckmaster	Penn State Univ.	(814) 865-3392	drb3@psu.edu
Rabi Mohtar	Purdue University	(765) 494-1791	mohtar@purdue.edu

* no station report received

Guests

Chris Palliser	Dexel, Hamilton, New Zeland	66 7 858 3787	chris.palliser@dexcel.co.nz
Brad Joern	Purdue University (AGRY)	(765) 494-9767	bjoern@purdue.edu
Al Heber	Purdue (ABE)	(765) 494-1214	heber@purdue.edu

The Regional Project meeting convened at 8 a.m. at Purdue University with a welcome from the Associate Dean of Research, Randy Woodson, and our host committee member Rabi Mothar.

H. Tyrell (CSREES Rep.) gave a report and led a discussion on perspectives from Washington relating to budgets, the Farm Bill, and water air quality. This was followed by a brief report from Project Administrator P. Wangsness (PA).

State reports were given.

Monday Afternoon

A brief presentation was given by Brad Joern on the Nutrient Management Planner program developed at Purdue University.

State reports were given.

Tuesday Morning

State reports were given.

Al Heber, gave a brief presentation on research currently being conducted in air quality at Purdue University.

The business meeting was called to order at 10:45 a.m. Stephen Herbert will be the chair next year. A motion was made, seconded, and passed that Zhengxia Dou be the secretary for next year.

It 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 Madison, WI in 2002. Meeting dates for the 2002 meeting were discussed. It was decided that the next meeting should be held on November 8th and 9th. This is the Friday and Saturday prior to the American Society of Agronomy Meeting that will be held in Indianapolis, IN. A field trip will be planned for Saturday afternoon.

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:

1. IFAFS grant possibilities regarding ammonia emissions;
2. beef cattle components
3. environmental models.

Each group met for 45 minutes.

The group reconvened at 12:00 p.m. 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 12:15 p.m.

NE-132 Regional Project Annual Report

November, 2001

Z. Dou & J. Ferguson

University of Pennsylvania

Objective 1 c ii. Characterize manure P for potential runoff loss.

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 University of Pennsylvania; the data were examined and interpreted together with cow performance parameters by all investigators.

Usefulness of findings

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.

Objective 1 c iii. Nutrient efficiencies in different cropping systems.

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.

Usefulness of findings

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.

Work plan for 2002

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.

Publications

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.

Dou, Z., D. T. Galligan, C.F. Ramberg, Jr., C. Meadows, and J.D. Ferguson. 2001. A survey of dairy farming in Pennsylvania: nutrient management practices and implications. J. Dairy Sci. 84:966-973.

Ferguson, J.D., Z. Dou, and C.F. Ramberg. 2001. An assessment of ammonia emissions from dairies in Pennsylvania. Proc. 2^nd Int’l Nitrogen Conference. Oct. 14-18, Potomac, MD.

Toth, J.D., Z. Dou, J.D. Ferguson, and D.T. Galligan. 2001. Nitrate leaching losses affected by nutrient inputs and crops. Proc. 2^nd Int’l Nitrogen Conference. Oct. 14-18, Potomac, MD.

Dou, Z., J.D. Toth, D. Galligan, C. Ramberg, and J.D. Ferguson. 2001. Nutrient losses to groundwater affected by fertilization and crops. 12^th World Fertilizer Congress. Aug. 3-9, Beijing, China.

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. Oct. 3-5, Raleigh, NC.

NE132 Committee Purdue University Research Report

Purdue University, West Lafayette Indiana

November 5 & 6, 2001

Station representative: Rabi H. Mohtar, Agricultural and Biological Engineering, Purdue University

Collaborators: Al Rotz, Heather Karsten and Jim Cropper (Penn State)

Jennifer MacAdam (Utah State)

Andrew Gillespie, Forestry; Keith Johnson, Agronomy; Mike Neary Animal Science; Jeff Volenec, Agronomy (Purdue University)

Faraj El-Awar (United Nations (formerly American University of Beirut))

Raghavan Srinivasan and Jimmy Williams (Blackland Research Center, TX)

Xingwen Chen (Tetra Tech, Inc.)

Graduate Students: Tong Zhai (Purdue University)

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.

Current 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 from Lebanon, gave quite satisfactory results as shown in Figure 1. Algorithm tests addressed interspecies competition in mixed pasture systems for light, water, and nutrients. The new version of the model can simulate growth and grazing of a pasture with multiple species using independently derived parameter sets for each individual species. This study also indented to model the tree effects in a typical silvopastoral system. The main factors considered include the filtering effect of forest canopy for light and rainfall, soil water depletion through evapotranspiration by tree crown, and nutrient uptake by the trees. The new algorithms for these tree effects, incorporated into the multispecies GRASIM, will result in an agroforestry model that can be easily applied to real world situation. A GIS interface will be implemented to take advantage of its capability to address spatial variability and graphical user interface. A sample simulation is shown in Figure 2. Further development involves a more complete integration of the GIS interface with the existing database.

Recent Publications:

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- . July 18-21, 1999. Toronto, Ontario, Canada.

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.

Zhai, Tong, 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, St. Joseph, MI 49085.

PROGRESS REPORT - REGIONAL RESEARCH PROJECT NE-132

Pasture Systems and Watershed Management Research Unit

USDA/Agricultural Research Service

University Park, PA

November 2001

PROJECT TITLE: Environmental and economic impacts of nutrient management on dairy forage systems

PRINCIPAL LEADERS: C. Alan Rotz and Matt A. Sanderson

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 Pennsylvania dairy farms should be encouraged, particularly when double cropped with corn, to reduce N leaching loss, reduce soil P accumulation, and improve farm profit.

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 southern Pennsylvania was simulated to evaluate the long-term impacts of these double-cropping strategies. Averaged over 25 years of weather, double cropping corn after rye silage reduced N leaching loss from the whole farm by 25% (8 lb N/ac/yr), increased total feed production by 6%, and increased annual farm profit by $50/ac of rye compared to a corn and alfalfa rotation. Using the rye as mulch provided a similar reduction in N leaching loss, increased feed production up to 3%, but reduced farm profit by $32/ac of rye. Thus, double cropping corn with winter rye is a good strategy for reducing N leaching from dairy farms, and farm profit can be improved when the rye is harvested as silage.

Weather has had a major influence on crop production in the Great Lakes states during the past century, but isolation of weather effects is difficult due to confounding effects of technological improvements in agriculture. A simulation study was used to identify climate impacts on the production of alfalfa, corn, and soybean during the period 1895-1996. DAFOSYM, CERES-Maize, and SOYGRO models were used to simulate crop growth, development and yield of the respective crops while holding all input variables except weather constant. Simulated corn and soybean yield series were found to increase with time since the late 1930's at most of the study sites due to increased precipitation and decreased potential evapotranspiration. Simulated yields supported previous research identifying a period of ‘benign climate’ that favored crop production in the region from 1954-1973, which was preceded and followed by periods of relatively greater yield variability. The study suggests that at least part of the observed yield increases in the region during recent decades have occurred as the result of wetter, less stressful growing season weather conditions.

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 Northern Germany. Animal numbers supported by the farm-produced forage decreased with greater use of grazing and increased with the use of higher yielding corn silage. The import of purchased feed was directly related to animal numbers, and the surplus N per unit of milk produced decreased with increased use of corn silage. Nitrogen was utilized most efficiently on the dairy farm when 50 to 80% of the forage produced and fed came from corn silage. Greater use of grazing decreased N volatilization loss but increased leaching loss because urinary N deposits on pasture were more quickly absorbed into the soil. Use of corn on the farm reduced N volatilization considerably because manure could be injected into the soil before spring planting. Higher levels of manure N in the soil caused small increases in denitrification. Total N losses per unit of milk produced increased with the use of grazing and decreased with greater use of corn.

Objective 1e. System Integration.

The Catskill and Delaware watersheds, which are primarily covered with forests and dairy farms, supply 90% of the water required for New York City. Phosphorus loading of these watersheds is a concern, and nutrient management plans are being implemented on dairy farms to reduce P loss to surface water. Management changes in crop production and feeding may be used to reduce the long-term accumulation of excess P, but farm profitability must be maintained or improved. Whole-farm simulation was used to evaluate the long-term effects of changes in production strategies on phosphorus loading and profitability of two farms in this region. Simulated farms maintained a long-term P balance if: 1) animals were fed to meet new NRC recommendations on P requirements, 2) the cropping strategy and land base used supplied all of the forage needed, 3) all animals were fed a high forage diet, and 4) replacement heifers were produced on the farm. The most economical strategy for reducing P loading was to reduce the supplemental mineral P fed to all animals to that needed to meet the new recommendations on P requirements. Intensifying the use of grassland and improving grazing practices also increased profit along with a small reduction in P loading. Thus, management changes can be made to prevent the long-term accumulation of soil P on these dairy farms while improving farm profitability.

Automatic (robotic) milking systems are just becoming available in the United States. A whole-farm analysis was used to determine the impacts of implementing this technology on a Jersey farm in southern Pennsylvania. Impacts included an increase in feed consumption, increased milk production, reduced labor use and costs, a large increase in the annualized cost of milking equipment, and a decrease in farm net return of $30,000 per year. When the Jersey animals were substituted with a higher producing Holstein herd, fewer animals were needed to produce the same level of income from milk sales. With fewer animals, one less robotic milking unit was required, reducing the initial investment by $175,000. With this scenario, the use of the automatic milking system provided a small ($5,000 per year) decrease in the long-term net return to the farm. When the animal numbers for either the Jersey or Holstein herds were increased to better match the full capacity of an automatic milking system, the long-term economic benefit improved to an $18,000 loss with the Jersey herd and an $8,000 increase in annual profit for the Holstein herd. As this technology is adopted in the United States, the greatest economic benefit can be expected on farms with smaller, high producing herds where the number of animals is well matched to the capacity of the milking system.

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.

4. Continue cooperation with Harrison (WA) on the analysis of grass production systems and nutrient management on western Washington dairy farms.

5. Continue development and application of DAFOSYM for the evaluation of various grazing systems used in the northeastern U.S. and elsewhere.

PUBLICATIONS:

1. Rotz, C.A. 2001. Mechanization: planning and selection of equipment. p. 763-768. In S.C. da Silva (ed). Proc. XIX International Grassland Congress, February 11-21, Sao Pedro, Sao Paulo, Brazil.

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 Pennsylvania dairy farms. Agron. J. 93:418-428.

3. Rotz, C.A., K.J. Soder and G.W. Roth. 2001. Environmental and economic impacts of a corn and rye double crop system on a Pennsylvania dairy farm. p. 166-170. Proc. American Forage and Grassl. Conf. Springdale, Arkansas. AFGC, Georgetown, TX.

4. Soder, K.J. and C.A. Rotz. 2001. Economic and environmental implications of four levels of concentrate supplementation in grazing dairy herds. p. 171-175. Proc. American Forage and Grassl. Conf. Springdale, Arkansas. AFGC, Georgetown, TX.

5. Rotz, C.A., C.U. Coiner and K.J. Soder. 2001. Economics of robotic milking on a dairy farm in the United States. pp. 115-122. In: T. Juliszewski (ed), Farm Work Science Facing the Challenges of the XXI Century. Proc. XXIX CIOSTA-CIGR V Congress. June 25-27, Krakow, Poland. Wageningen Pers, Wageningen, The Netherlands.

6. Rotz, C.A., A.N. Sharpley, W.J. Gburek, M.A. Sanderson and L.D. Satter. 2001. Production and feeding strategies for phosphorus management on dairy farms in New York. Paper No. 01-2013, ASAE, St. Joseph, MI.

7. Soder, K.J. and C.A. Rotz. 2001. Economic and environmental impact of four levels of concentrate supplementation in grazing dairy herds. J. Dairy Sci. (in press).

8. Andresen, J.A., G. Alagarswamy, J.T. Ritchie, C.A. Rotz and A.W. LeBaron. 2001. Weather impacts on maize, soybean, and alfalfa production in the Great Lakes Region, 1895-1996. Agron. J. 93:1059-1070.

9. Rotz, C.A. and C.U. Coiner. 2001. Dairy Forage System Model, Reference Manual. Available from: http://pswmru.arsup.psu.edu

10. Sanderson, M.A., C.A. Rotz, S.W. Fultz and E.B. Rayburn. 2001. Estimating forage mass with a commercial capacitance meter, rising plate meter and pasture ruler. Agron. J.: (in press).

NE-132 Regional Project Report:

November 5-6, 2001

Richard A. Kohn

Department of Animal and Avian Sciences

University of Maryland

College Park, MD 20742

E-mail: rkohn@wam.umd.edu URL: http://www.inform.umd.edu/ManureNet

Progress of Work and Principal Accomplishments

Objective 1b. Herd Nutrient Utilization Strategies

Dairy Herd Management Practices That Impact Nitrogen Utilization Efficiency

Improving the efficiency of feed N utilization by dairy cattle is the most effective means to reduce nutrient losses from dairy farms. The objectives of this study were to quantify the impact of different management strategies on the efficiency of feed N utilization for dairy farms in the Chesapeake Bay Drainage Basin. A confidential mail survey was completed in December 1998 by 454 dairy farmers in PA, MD, VA, WV and DE. Nitrogen intake, urinary and fecal N, and efficiency of feed N utilization were estimated from survey data and milk analysis for each herd. Average efficiency of feed N utilization for milk production by lactating dairy cows (N in milk / N in feed x 100) was 28.4% (SD=3.9). On average, farmers fed 6.6% more N than recommended by the National Research Council resulting in a 16% increase in urinary N and a 2.7% increase in fecal N. Use of monthly milk yield and component testing, administration of bovine somatotropin (BST), and extending photoperiod with artificial light each increased efficiency of feed N utilization by 4.2 to 6.9% while use of a complete feed decreased efficiency by 5.6%. Increased frequency of ration balancing and more frequent forage nutrient testing were associated with higher milk production, but not increased N utilization efficiency. Feeding protein closer to recommendations and increasing production per cow both contributed to improving efficiency of feed N utilization.Objective 2c. Tools

Objective 2c. Tools

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 U.S. for MUN analysis. For the Foss 6000, Bently Chemspec, Skalar and CL 10 methods, greater than 98% of the variation in measured MUN was attributed to farm to farm differences. For the Foss 4000 system, less than 60% of the variation in MUN was attributed to farm to farm differences. The Foss 4000 system also underestimated the higher values, and was not consistent across labs. If using MUN to estimate urinary nitrogen excretion or evaluate protein nutrition, the Foss 6000, and chemical methods would provide similar results to each other, but the Foss 4000 would provide variable results depending on the lab.

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

Excel 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 U.S. protectorates and 27 countries.

Usefulness of Findings

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.

Work Plans for 2000-2001

An additional field study is currently being conducted to introduce the use of milk urea nitrogen (MUN) to fine tune diets on dairy farms in Maryland. In this study, predictions of N intake using MUN will be compared to N intake measurements based on diet composition and feeding practices.

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.

Farm balance worksheets will be used to collect more data on farms in Maryland and these results will be summarized.

Publications

In Press

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.

Proceedings

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. Oct. 3-5, 2001, Raleigh, NC.

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. Oct. 3-5, 2001, Raleigh, NC.

2001 NE-132 REPORT

UNIVERSITY OF MASSACHUSETTS

DEPARTMENT OF PLANT AND SOIL SCIENCES

Stephen J. Herbert

1. Project report

Nutrient Management Planning Aid

Our 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 University of Massachusetts Extension and Massachusetts USDA Agencies with concerns and obligations regarding nonpoint source pollution control from animal feeding operations. FarmSoft is a computer worksheet program used to generate whole-farm nutrient management plans for crop and livestock farms. Inputs required include soil and manure test analyses, crop yield goal and crop history, type and number of animal groups, previous and current rate of manure application, and method of incorporation. The program calculates manure and/or fertilizer rates to meet nutrient need and indicates fields with excess nutrients.

The first version of FarmSoft was developed by Univ. of Massachusetts Extension in 2000. The updated second version of the program is also capable of calculating a site vulnerability index, and highlights any major environmental concerns associated with individual fields. The planner may then choose from a list of major conservation practices to reduce the risk of non-point source pollution. The program can search on-line for soil properties based on soil type name. FarmSoft generates a report of the nutrient management plan minimizing the time commitment of the planner. Simplicity, ease of use, and transferability have been guiding principles in the design of FarmSoft.

Nitrogen Sufficiency or Excess in Corn Production

In 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 Connecticut has shown 0.5 to 2.0 g/kg to be the optimum range for mature field corn and in Massachusetts we have shown this to be much higher for immature field corn and sweet corn. The optimum for milk stage was found to be 3.4 to 5.0 g/kg. For field corn the recommended sampling calls for taking a stalk sample from the 15 to 34 cm section of the plant. This necessitates farmers who harvest corn for silage raising the forage chopper cutting height which is problematic for farmers. Part of this research has involved long-term (11 years) corn-cover crop rotations with variable nitrogen rates.

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.

4. Publications.

Liu, X., and S.J. Herbert. 2001. Ecological impacts of cover crops. Journal of Applied Ecology 12(1): 24-29

Ding, 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 of Chemistry, Cambridge, UK, p53-61.

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, UK. p261-271.

NE-132 Regional Research Project: 2001 Annual Report

Rhonda Miller

Utah State University

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. Charlotte, NC.

NE-132 PROGRESS REPORT FOR 2001

CORNELL UNIVERSITY

DEPARTMENT OF CROP AND SOIL SCIENCES

Gary W. Fick and H.G. Gauch

Progress of Work and Principle Accomplishments

Objective 1a iii. Improvement of crop models.

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.

Objective 1d iii. Methods of measuring and predicting pasture yield.

We 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 OM for each Mg/ha of unvacuumed herbage dry weight. This indicates that without vacuuming, clipping small plots underestimated herbage mass by about 5% with the methods used in our study. The costs of stubble vacuuming exceed the value of improved accuracy that could be gained.

Usefulness of the Findings

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.

Work Planned for Next Year

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).

Publications.

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, Madison, WI.

NE-132 Regional Research Project: 2001 Annual Report

Joseph H Harrison

Department of Animal Sciences

Washington State University

I. Progress of Work and Principal Accomplishments

A. Objective 1, Section 1b. 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 milked/day

B. Objective 2, Section 2c. Use of milk allantoin to estimate rumen microbial protein flow.

Two experiments were conducted to look at sampling method and effect of rBST on milk allantoin concentration and output in milk.

C. Objective 1, Section 1a, subsection ii.

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).

II. Usefulness of findings

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.

III. Work Plan for 2001

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.

IV. Publications

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, and D Davidson. 2001. Effect of diet and sampling on milk allantoin output. J Dairy Sci 84:163 (Suppl 1).

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 Harrison, W Schager, D Davidson, S Chen, C Stockle, F Hoisington, and C A Rotz. 2001. Nutrient intake and body characteristics of dairy cows in Washington state dairy herds producing in excess of 12,730 kg of milk annually. J Dairy Sci 84:122 (Suppl 1).

Johnson, L M, J H Harrison, W Schager, D Davidson, S Chen, C Stockle, F Hoisington, and C A Rotz. 2001. Characteristics of forages and TMR fed to dairy cows in Washington state dairy herds producing in excess of 12,730 kg milk annually. J Dairy Sci. 84:122 (Suppl 1).

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. Washington State Dairy News. Vol.10 No. 2, March.

Johnson, L, and J H Harrison. 2001. Effects of mechanical processing on particle size, pack density, and aerobic stability of corn silage. Washington State Dairy News. Vol.11 No. 3, April.

Johnson, L, and J H Harrison. 2001.Kernal processing:Fermentation changes in the silo due to maturity and mechanical processing of corn silage. Washington State Dairy News. Vol.12 No. 4, May.

Johnson, L, and J H Harrison. 2001. Kernal processing article # 4: Measuring rumen digestibility of processed corn silage using the macro in situ technique. Washington State Dairy News. Vol.13 No. 5, August

Harrison, J H, and L Johnson. 2001. Management practices that enhance the nutritive value of ensiled forages. Proceedings of the 10^th International Symposium on Forage Conservation, Brno, Czech Republic.

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 Washington state dairy farms using a computer simulation model (DAFOSYM). Proc. Int. Production and Environmental Issues Conference.

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 dairy cows. Washington State Dairy News. Vol.10 No. 6, September.

NE-132 Regional Project: 2001 Annual Report

University of Wisconsin

Contributer: D. K. Combs

Objective:

1b. Herd Nutrient Utilization Strategies

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.

1 d. Pasture and grazing: iii. Methods of measuring and predicting pasture yield

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.

II. Usefulness of findings

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.

Work plan for 2002

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.

Publications

2001: 1 refereed publication, 3 refereed papers submitted (2 in review, one is accepted), 2 abstracts and 9 conference proceedings published.

Refereed Publications:

Riesterer, J. L. , D. J. Undersander, M. D. Casler, D. K. Combs. 2002. Quality of Forage Stockpiled in Wisconsin. J. Range Management . Accepted

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. 85: (Submitted 9-12-01)

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 9-12-01)

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 USA. Agron. J. 92:740-747.

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.

Abstracts:

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).

Conference Proceedings:

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. Madison.

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. Madison. WI.

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. June 25-29. Quito, Ecuador. Babcock Institute, Univ. Wisc-Madison.

Grummer, 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. Quito, Ecuador. Babcock Institute, Univ. Wisc-Madison.

Combs, D. K. 2001. Feeding high producing cows on pasture. In Proc. Babcock Institute Short Course on Dairy Production. June 25-29. Quito, Ecuador. Babcock Institute, Univ. Wisc-Madison.

Combs, D. K. 2001. Managing pastures for high producing dairy cattle. . In Proc. Babcock Institute Short Course on Dairy Production. June 25-29. Quito, Ecuador. Babcock Institute, Univ. Wisc-Madison.

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. April 4-7, 2001 Belo Horizonte MG. Brazil.

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. April 4-7, 2001 Belo Horizonte MG. Brazil.

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. Madison, WI.

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. July 11-12, 2000. Debuque IA.

Combs, D. K. 2000. New tests to measure forage digestiblity and bypass protein in forages. In Proc. Wisconsin College of Veterinary Medicine Post Graduate Conference, June 17, 2000. Univ. Wisc.. Madison.

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