masseyr – Livestock and Poultry Environmental Learning Community

March 5, 2019July 8, 2020

Integrating Manure into Feed Ration Optimization

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* Presentation slides are available at the bottom of the page.

Abstract

Ration optimization models currently minimize the purchase price of feeds used to meet nutrient requirements. Not included in optimization models is the value of manure nutrients resulting from ration alternatives. This project extends the linear program that is used to minimize ration cost to include the value of manure excreted and stored. Microsoft EXCEL’s Solver GRG Nonlinear Add-in is used to optimize the integrated decision because of the non-linear aspects of manure excretion as a function of feed fed.

Several economic and production changes over the last 10 years warrant an investigation of the impact of optimizing both feed and manure decisions simultaneously. Distillers Dried Grains with Solubles (DDGS) have become a common feed high in phosphorus, lessening the need for inorganic phosphorus sources. Including DDGS in the diet also increases the manure concentration of phosphorus. If phosphorus is needed on nearby crop fields, there is potential to increase manure value while simultaneously reducing feed cost. In contrast, feeding phytase may reduce feed cost, while reducing manure value if phosphorus in manure is valued. Feeding synthetic amino acids can also reduce feed cost while reducing the amount of nitrogen excreted and available as a fertilizer in the manure. Adding to the importance of considering manure value is the increased costs of fertilizers. Manure is increasingly seen as a viable alternative to commercial fertilizers and might affect the whole farm profitability if included in the ration cost decision.

This project considers swine rations and examines how they might have changed during the past 10 years if manure value had been incorporated into the ration optimization decision. We will attempt to determine when manure fertilizer value relative to feed costs justifies integrating feed and manure optimization. Results indicate that incorporating manure value into the optimization routine would change some diet formulations.

Why Consider Manure Nutrients When Balancing Rations?

The value of manure supplied nutrients (N, P and K) has increased significantly over the past decade. Feedstuffs, such as DDGS, have been incorporated into the diets in ways that reduce the need for P supplementation. These developments have moved manure from a waste product to a co-product in livestock production. By integrating feed and manure management decisions it was hypothesized that profit could be improved.

What Did We Do?

The 2012 version of the National Swine Nutrition Guide (NSNG) ration software contains an optimization model for least cost ration formulation that calculates the potential manure value associated with different optimized diets. This recognition of the value of manure is an important contribution.

We incorporated the value of manure (as estimated by the NSNG) into the least cost ration optimization routine so that the objective function changed from minimizing the cost of feed to minimizing the net cost of feed. Net diet cost was defined as the cost of feed less the value of manure. Optimization of this equation required the use of the GRG non-linear optimization routine of Microsoft EXCEL.

This project evaluated least cost swine rations and how they might have changed during the past 10 years if manure value had been incorporated into the ration optimization decision. We specifically examined rations for 50-100 lb. and 200-250 lb. pigs. Rations were optimized with the following limitations: 1) manure was/was not included in the objective function; 2) DDGS were/were not allowed as a feedstuff in the rations.

What Have We Learned?

Assuming that the full value of the manure could be obtained, incorporating manure into the least cost ration optimization reduced net diet cost seven of the last 10 years for 50-100 lb. and 200-250 lb. pigs when DDGS were allowed in the diets. The ten-year mean improvement in net diet cost was $0.61/ton with a range from $0 to $8.41/ton of feed. More typically differences were small, exceeding $1.00/ton only in 2005 and 2006. Increasing manure value required increasing feed cost by an a 10-year average of $1.14/ton. The uncertainty in extracting manure value may make farmers hesitant to increase feed cost in hopes of capturing additional manure value. Two years may provide insight into the opportunity to incorporate manure value into the least cost feed decision. In 2006, a savings of $8.41/ton of feed fed was obtained by including 40% DDGS in the 50-100 lb. pig diet; this savings required increasing the feed cost by $1.76/ton resulting in a $10.18/ton increase in manure value in associated excreted nutrients. In 2009, a net ration savings of $.61/ton was obtained by eliminating phytase which was in the original least cost ration formulation. Phytase reduced the need for expensive phosphorus feedstuffs but not sufficiently when the value of manure was considered.

Future Plans

Non-linear optimization routines may find local optima rather than a global optimum. A procedure needs to be developed that insures that the global optimum is found before incorporating manure into the least cost ration decision will become widespread.

Authors

Dr. Ray Massey, Extension Professor, Agricultural and Applied Economics, University of Missouri, masseyr@missouri.edu

John Lory, Extension Associate Professor of Extension, Division of Plant Science, University of Missouri

Marcia Shannon, Associate Professor, Swine Nutrition, University of Missouri

Additional Information

The 2012 version of the National Swine Nutrition Guide can be found at the U.S. Pork Center of Excellence (https://www.usporkcenter.org/product/national-swine-nutrition-guide/)

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

Integrating Manure Into Feed Ration Optimization from LPE Learning Center

March 5, 2019March 26, 2019

Integrating Probable Fieldwork Days into Nutrient Management Plans

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Abstract

Weather conditions impact land application of manure. Wet soils hinder equipment from accessing fields. Regulations prohibit application on frozen or snow cover soils. Uncertain soil and atmospheric conditions can cause the best plans to fail. Nutrient management plans that are expected to succeed might fail given any particular year’s weather. Incorporating fieldwork days information into nutrient management plans can make them more robust to uncertain weather conditions.

The USDA publishes the number of fieldwork days for different crop reporting districts within states. These data are from field reporters who provide their opinion on the number of days that were available for farmers to conduct fieldwork such as disking, planting and harvesting. USDA Fieldwork Days data cover the growing season (approximately April to December). Estimates of fieldwork days do not exist for the non-growing season (approximately December to April). However, certain states have agricultural weather station networks that collect soil temperature and other critical information that can be used to estimate the number of fieldwork days that exist for manure application within regulatory limits.

This project integrates fieldwork days from the USDA Fieldwork Days data with the Missouri Agricultural Weather Station Network winter soil temperature and precipitation data for the corresponding crop reporting district. This compiled database gives a complete year of fieldwork day estimates. The data are used in a model that allows nutrient management planners to incorporate climatological impacts into their land application plans. Users specify their equipment complement and size, quantity of manure, and desired beginning and ending dates. The model reports output in a cumulative distribution function that estimates the probability of completing fieldwork within the specified parameters and a sensitivity table of ending dates.

Why Consider Fieldwork Days for Nutrient Planning?

We currently have no mechanism to evaluate the feasibility of implementing nutrient management plans. A plan that successfully finds sufficient fields for using nutrients in manure may fail because there is insufficient time to apply manure with the designated equipment. Incorporating fieldwork day information into the nutrient management planning process could make plans more robust, informing the planner and farmer how likely the plan will succeed.

What Did We Do?

This project developed two spreadsheets that help nutrient management planners incorporate USDA and climatic data into their plans to estimate the likelihood of successfully completing the plan objectives.

The first spreadsheet incorporates fieldwork day data from the USDA with machinery management decisions to estimate the probability of completing manure application within a planned window. This spreadsheet and data report the number of days in a week when fieldwork can be done in various regions of the state during the period April through November. The second spreadsheet integrates soil temperature and precipitation data from the Missouri Agricultural Weather Station Network to estimate the probability of completing manure application within a planned window during the months of December through March period.

Users specify their equipment complement and size, quantity of acres receiving manure, desired beginning and ending dates for manure application, and hours per day and days per week they can apply manure. The model reports output in a cumulative distribution function that estimates the probability of completing fieldwork within the specified parameters and a sensitivity table of ending dates.

Sample output of the probability of completing necessary fieldwork.

What Have We Learned?

Plans do not normally consider the feasibility of accomplishing manure application within an appropriate time frame. Missouri fieldwork day data indicate that time available for field work varies significantly over the year and within the state at any given time. For example, a nutrient management plan that requires 100 hours of application time in northwest MO during the month of April would be successful 78% of the time. The same nutrient management plan needing 100 hours of fieldwork during February would be successful 40% of the time. In April the median number of fieldwork days 11.5 days compared to 8.3 days in February.

Sample imput screen for describing the manure application parameters.

Future Plans

We will expand the tool beyond Missouri. We are looking for funding opportunities to integrate it into our nutrient management plan document generators.

Authors

John Lory, Associate Professor of Extension, Plant Science Divsion, University of Missouri loryj@missouri.edu

Dr. Ray Massey, Professor of Extension, Agricultural Economics, University of Missouri

Pat Guinan, Assistant Professor of Extension, Soil and Environmental Systems, University of Missouri

Additional Information

The spreadsheets that incorporates fieldwork days into manure management decisions can be obtained at swine.missouri.edu/manure/ under the link names of Probable Fieldwork Days and Probable Winter Fieldwork Days.

Acknowledgements

Scott Gerlt and Brent Carpenter of the Food and Agriculture Policy Institute created the initial spreadsheet tool.

Integrating Probable Fieldwork Days into Nutrient Management Plans from LPE Learning Center

March 5, 2019March 6, 2019

Costs of Manure Application and Transport

When talking about the value of manure, costs are reported in terms of dollars. While reporting in terms of dollars is usually helpful, it is not the only metric for discussing costs. Any resource that is required to accomplish a task can be considered a cost. With this in mind, this page will discuss the cost of manure distribution in terms of dollars and time. The limiting resource, dollar cost or hours required, determines how manure is distributed. Hours could be converted to dollars but that would possibly obscure the management of these costs.

Factors Influencing Cost of Manure Management

The three major activities that influence the cost of manure management are loading, transporting and land applying. Each activity can require its own specialized equipment and can constrain the use of the manure. For example, except for an external manure storage structure, loading is best done when animals are not present and thus limited to those time periods. Transportation can be time consuming depending on the distance traveled and the amount of water hauled in the manure. Land applying requires proper soil and plant conditions and specialized equipment.

Livestock manure is either liquid, slurry or solid. Different types of manure will have different impacts on the cost of distribution. For example, solid manure can usually be hauled farther for less money because less water is being transported. Liquid manure, because of its high water content, can’t be transported as far but low cost irrigation systems can be used to distribute it relatively inexpensively. This page will address each manure type separately. Because the dollar cost of managing manure is so dependent on location, type of livestock, form of manure, availability of land, etc. No dollar estimate will be given in this page. The quickest way to get a cost estimate would be to contact a custom manure hauler and ask the price charged for different services.

The table below summarizes the relative costs of manure application and distribution. When reading it, compare the costs within a column, rather than within a row. In other words, use it to compare the cost of loading, transportation, or land application for each type of manure. The more dollar signs ($) a manure type has, the more expensive it is relative to the other types of manure. Click on a type of manure in this table to be taken to a description of why different manures will have different costs.

**Summary of Manure Application and Distribution Costs**
Manure Type	Loading	Transportation	Land Application
Solid Manure
Fresh	$$	$$	$$$
Stockpiled	$$$	$$	$$$
Slurry Manure
Tanker	$	$$$$	$$$
Dragline hose	$	$$$	$$
Liquid Manure
Dragline hose	$	$$$	$$
Irrigation system	$	$	$

Custom application

Because much of the equipment used in manure application is unique to manure application, many livestock producers choose to not own the equipment but rather hire custom operators to handle their manure. Custom operators can lower the cost of manure management, relative to owner operated equipment, by spreading the cost of expensive equipment over more units. Many custom operators can also apply the manure more quickly due to experience and because they have larger equipment or multiple pieces of equipment. Because they work for many livestock producers, they may not be able to apply an individual’s manure at opportune times. This uncertainty of when the manure will be applied is a cost that needs to be taken into account. Contracting Certified Manure Haulers contains instructions for comparing custom hauling with producer hauling of manure.

Livestock manures are an excellent source of organic nutrients. However, they are generally more expensive to transport and land apply than more concentrated commercial fertilizers. The cost of manure transport and distribution are critical to understand and manage in order to derive maximum value from manure. A research project completed in the late 1990’s includes this information. The actual costs presented may no longer be relevant but the conclusions are still valid.

A spreadsheet to estimate the cost of hauling various types of manure can be obtained at University of Missouri.