Final Report for LNC94-071
[Note to online version: The report for this project includes a table and appendices that could not be included here. The regional SARE office will mail a hard copy of the entire report at your request. Just contact North Central SARE at (402) 472-7081 or firstname.lastname@example.org.]
The objective of this work was to develop a videotape series demonstrating improved grazing practices particularly applicable to forage species and environmental conditions found in the upper Midwest. The first tape “Introduction to Managed Grazing” initiates the series by discussing the importance of ruminant livestock to the Iowa economy, the benefits of incorporating grazing into farming enterprises and the advantages and limitations of utilized managed grazing practices. The second tape “Pasture Plants” describes methods of improving pasture productivity by considering the effects of grazing intensity on photosynthetic capacity through leaf area and nutrient absorption through root growth and the habit and management of growth in the forage species found in Midwest pastures. The third tape “Animal Management” describes the technical aspects of managing a controlled grazing system including the determination of stocking rates and the size, number, shape and placement of paddocks needed to optimize profitability of different livestock enterprises and also placement of water systems, gates and milking facilities, management of reproduction and internal parasite control. The fourth tape “Fencing and Watering Systems” describes the options in fencing and watering equipment currently available and the considerations in the proper use of this equipment for a managed grazing system. The final tape “Year Around Resource Management” describes the productivity and nutritive value of forage resources available for grazing in the different seasons of the year and methods of matching the numbers, genetics and management of beef cows, beef stocker steers, dairy cows or ewes with the forages available for grazing in each season to optimize enterprise profitability. These tapes were distributed to the county extension offices in Iowa and have been sold at a nominal charge to 410 individuals since their release.
As a supplement to the videotape series, a book entitled Pasture Management Guide for Livestock Producers has been prepared. The book consists of 5 sections: (1) Managing Pasture Plants discusses the characteristics of forage species common in the Midwest, the mechanism and control of plant growth in grazing systems, and different pasture weed control, fertilization, management and renovation strategies; (2) Livestock Management discusses the nutrient requirements of different species and classes of grazing animals as affected by physiological state, health problems associated with grazing systems, management of reproduction or milking in grazing systems, fencing and watering options and the need and use of other feed resources to supplement grazing animals; (3) Planning for Improvements in Grazing Systems discusses the integration of plant and animal resources to optimize grazing both during the summer and winter, calculation of present carrying capacity using forage mass and intake and seasonal carrying capacity using the soil types within the pasture; and paddock layout; (4) Monitoring and Evaluating the Grazing System discusses the type of records needed to register production and management decisions and to plan future management of feed and animal resources; and (5) Managing Risk in Grazing Systems describing the integration of pasture management systems within the level of risk acceptable to the producer. Examples of worksheets to calculate the number and/or size of paddocks or the carrying capacity of pastures are included. This book will be offered through Iowa State University extension at a nominal charge.
Although incorporation of forages in farming systems results in less soil erosion and water pollution and greater wildlife habitat than row crop production, profitability of forage use must be equal or greater to row crop production to increase their use in farming. Considerable research has demonstrated that the profitability of forage-based livestock production systems would be significantly improved by improving management during summer and winter. Best management practices for an individual farm are site-specific so training producers improved grazing management can not be done with a single set of steps as readily as row crop production. Producers need a general set of guidelines which they can manage differently depending on the annual variations in environmental and economic factors on their own farm.
Videotapes provide a valuable means of demonstrating improved farming practices. Few videotape series on grazing management are available in the upper Midwest. Those available have emphasized economic and environmental benefits, but have not demonstrated technical considerations. The objective of this project was to develop a videotape series demonstrating improved grazing practices in the Upper Midwest. The 5-tape series of videotapes included: (1) Introduction to Managed Grazing; (2) Pasture Plants; (3) Animal Management; (4) Fencing and Watering Systems; and (5) Year Around Resource Management. The videotapes were prepared and copied by October, 1995. They have been distributed to each Iowa county extension office and 410 copies have been sold.
As a supplement to the videotape series, a book entitled Pasture Management Guide for Livestock Producers has been prepared. This full color publication discusses and demonstrates the subjects discussed in the videotape series in more detail and also presents information on topics not provided in the videotapes. The book consists of 5 sections: (1) Managing Pasture Plants discusses the characteristics of forage species common in the Midwest, the mechanism and control of plant growth in grazing systems, and different pasture weed control, fertilization, management and renovation strategies; (2) Livestock Management discusses the nutrient requirements of different species and classes of grazing animals as affected by physiological state, health problems associated with grazing systems, management of reproduction or milking in grazing systems, fencing and watering options and the need and use of other feed resources to supplement grazing animals; (3) Planning for Improvements in Grazing Systems discusses the integration of plant and animal resources to optimize grazing both during the summer and winter, calculation of present carrying capacity using forage mass and intake and seasonal carrying capacity using the soil types within the pasture; and paddock layout; (4) Monitoring and Evaluating the Grazing System discusses the type of records needed to register production and management decisions and to plan future management of feed and animal resources; and (5) Managing Risk in Grazing Systems describing the integration of pasture management systems within the level of risk acceptable to the producer. To emphasize topics of particular interest, sidebars on such subjects such as incorporation of grazing in dairy or horse operations and bloat control are included. Furthermore, examples of worksheets to calculate the number and/or size of paddocks or the carrying capacity of pastures are included.
To develop a videotape series demonstrating improved grazing practices particularly applicable to forage species and environmental conditions found in the upper Midwest.
To prepare a full color publication discussing and demonstrating the subjects discussed in the videotape series in more detail and also present information on topics related to grazing that were not included in the videotapes.
A series of five videotapes ranging from 12½ to 21 minutes were prepared. As soon as investigators were notified in March, 1994 that we would receive funding, we contacted Roger Brown in the Iowa State University (ISU) Extension Communications Department to arrange for a producer. Mr. Brown assigned Brian Menz as our producer. At a meeting with Mr. Menz in May of 1994, a schedule was arranged for the production of the series. Top priority items were script preparation and recording in pastures so that scenes pertaining to early spring grazing were available when editing. The script for the videotape “Managed Grazing: Fencing and Watering” was written by Ann Cowen and prepared by June 15, 1994. The scripts for the videotapes entitled “Managed Grazing: Introduction to Managed Grazing” and “Managed Grazing: Animal Management” were written by Dan Morrical and was prepared by July 1, 1994. The outline for the script for the videotape entitled “Managed Grazing: Year Round Resource Management” was prepared by Jim Russell by August 1, 1994 and the script was written by a professional writer, Kathy Eastman, by August 15. The script for the videotape entitled “Managed Grazing: Pasture Plants” was written by Steve Barnhart, Ken Moore and Bob Dayton and was prepared by October 1, 1994. All scripts were reviewed by the members of the Animal Management Issue Team of the Leopold Center for Sustainable Agriculture prior to their use.
Although scripts were not prepared yet, videotaping began in May, 1994 and continued throughout the project (Table 1). The videotapes entitled “Managed Grazing: Introduction to Managed Grazing,” “Managed Grazing: Animal Management” and “Managed Grazing: Fencing and Watering” were assembled by Brian Menz during November, 1994 with the assistance of Claes Jonasson in the preparation of graphics. These tapes were initially edited by the information specialists who wrote each script with Brian Menz in early January and these tapes were placed on a continuous videotape to be shown at the Iowa State University “Management Intensive Grazing” Conference, held on January 24 and 24, 1995.
Because of the need for winter footage, preparation and editing of the videotape entitled “Managed Grazing: Year Round Resource Management” did not begin until April, 1995. Because of the need for additional spring footage, preparation and editing of the videotape entitled “Managed Grazing: Pasture Plants” did not begin until June, 1995. In July and August, 1995, tapes were finally reviewed by all investigators and final footage of more desirable scenes to emphasize a point were taped in August, 1995.
Videotapes were sent to Minnesota to be copied in August, 1995. In September, 1995, one copy of each set of videotapes was sent to every county extension office in Iowa. In addition, the availability of the series for sale was announced both in the print media (See appendix A) and on various computer bulletin boards.
In summer, 1996, a questionnaire evaluating the series was sent to each county extension office and to each of the purchasers (See appendix B).
In November, 1995, a meeting was held between Steve Barnhart, Dan Morrical, James Russell, Ken Moore and Charles Brummer to discuss the preparation of the written manual which would support the videotape series. At that meeting an outline was prepared (See appendix C) and writing assignments were made. Included in the authors was Dr. Peggy Miller because of her expertise in horse nutrition. In December, 1995, a freelance writer was identified, but she declined the position early in 1996. Therefore, in the spring of 1996, another freelance writer/editor, Merlin Pfannkuch, was hired. Original drafts for the publication were sent to Mr. Pfannkuch in August, 1996, and the first draft of the entire publication was prepared by September, 1996. Editing continued through the fall and winter of 1996 into 1997. In March, 1997, Ames Laboratory and Extension Communications Services was contacted to assist in graphic design and production. Photographs for the publication were identified in June 1997. Editing and layout continued through 1997 and into 1998. The publication went to press in June, 1998 was completed on June 23, 1998. It will be distributed to each extension area livestock specialist and cropping specialist in Iowa and will be sold at a nominal charge by order from other individuals.
Managed Grazing Videotape Series
The first videotape in the series entitled “Managed Grazing: Introduction to Managed Grazing” was written by Daniel G. Morrical of the Animal Science Department at Iowa State University. This videotape begins with a discussion of the importance of beef cattle, dairy cattle and sheep to Iowa’s economy, emphasizing that production of these species contributes $3 billion in person income to farmers and workers in related industries with Iowa. Because feed costs represent the single largest expense for production of livestock, maximum use of grazing will maintain a viable livestock industry by improving competitiveness. Furthermore, the use of pastures will reduce soil erosion, reduce pollution, improve wildlife habitat, improve water quality, and improve sustainability. Unfortunately, producers have not made good use of their pasture resources. With planning, however, farmers can develop a controlled grazing system which improves the profitability of forage-based livestock production. The limitations of controlled grazing are: the initial investment, the time commitment for labor, and the mental commitment to management. Controlled grazing systems, however, will: increase pasture production, increase forage quality, prevent excessive grazing selectivity and, thereby, maintain high quality forage species, improve manure distribution and nutrient recycling and improve animal handling and management. In order to properly manage a controlled grazing system, the seasonal variation in the production rates of various forage species must be considered. The net economic returns from a controlled grazing system are affected by the fencing costs as related to the number and size of paddocks, the watering system, renovation and fertilization costs of the pasture and production of animals and hay. The significance of utilizing controlled grazing is emphasized by quotes from Mike Hunter, Steve Hopkins and Don Faidley who are farmers with different enterprises.
The second videotape is entitled “Managed Grazing: Pasture Plants” was written by Stephen K. Barnhart and Kenneth Moore from the Department of Agronomy at Iowa State University with assistance from Robert Dayton with the USDA Natural Resource Conservation Service. This videotape emphasizes that grazing management considers the growth requirements and characteristics of pasture plants, nutrient needs of animals, the economics of utilizing the system and the daily decisions that are part of the system. Plant growth needs photosynthesis, respiration, and uptake of water and nutrients and regrowth. Photosynthesis requires adequate leaf area which might be limited by excessive grazing. Energy produced during photosynthesis will be used sequentially for respiration and maintenance, growth of leaves, roots and seeds and regrowth. An abundant root system is required by plants to optimize nutrient uptake. Root growth, however, will also be limited in plants in which leaf area is limited by excessive grazing. Not only will a stunted root system inhibit nutrient uptake, but it will also contain less of the storage carbohydrates needed for regrowth. The regrowth of a plant is dependent on its leaf shape, leaf arrangement, growth habit and response to environmental conditions at its location. Pasture grasses send up a tiller from its base which may produce new leaves or, if allowed to mature, a fibrous stem with a seed head. Each leaf has a bud at its based from which a new basal tiller may grow if the vegetative tiller is clipped by mechanical harvest or grazing. The growing points of legume forage species are located where leaves attach to stems and from dormant buds at the stem base of each plant. When plants are grazed, rapid regrowth from these crown buds will occur. Because leaves are digestible, palatable, and high in protein, it is particularly valuable to have leafy growth of forage plants. To optimize management of pastures, the growth habit of different pasture plants must be considered. Cool season grass species have 40 to 60% of their growth before summer and little growth during summer. Legume forage species grow nearly as well during summer as during spring and, therefore, will maintain forage production throughout the season. Warm season grass species have 60% of their growth in June and July and, therefore, can compliment the cool season grasses. The final component involved in plant growth management is the daily decisions regarding when and where to move animals as it relates to the season of grazing. The fewer the number of paddocks in a rotational grazing system, the longer that animals must remain on a given paddock particularly in midsummer. During this period, the amount and quality of consumed forage will be reduced. Since it takes 5 to 6 days for regrowth to begin after grazing, however, it is essential to allow 35 to 45 days of rest before grazing a given paddock again during midsummer. Because of the rapid growth during spring, paddocks may be grazed more frequently. This videotape ends with a quote from Steve Hopkins discussing his considerations on when and where to move his dairy herd in a rotational grazing system.
The third tape in the series is entitled “Managed Grazing: Animal Management” and was written by Daniel G. Morrical from the Animal Science Department at Iowa State University. This videotape primarily gives guidelines on designing the paddock system for a rotational grazing system. Factors which need to be considered in developing a rotational grazing system include the size and production stage of the animal as it affects feed intake and bite size as related to the quantity of available forage, forage nutritive value as affected by plant maturity, pasture productivity as affected by soil quality and forage species of the pasture and the planned length of the grazing season. Paddock size and number are related to stocking rate and the length of the grazing interval and, therefore, stocking rate may be calculated from estimates of the forage which is available for grazing, the feed intake of the animal and the length of the grazing interval. In a 6 paddock grazing system with 6 days of grazing and 30 days of rest in a pasture with a sward height of 10 inches and 1200 lb cows, the stocking rate may be calculated by the following method:
Pounds of available forage = 10 inches sward height x 200 lb forage/inch x 50% removal for grazing = 1000 pounds
Pounds of forage consumed = 1200 lb x 3% of body weight feed consumption per cow = 36 pounds
Cow-days/acre = 1000 pounds available forage/36 pounds = 27 cow-days/acre
Stocking rate of pasture = 27 cow-days/acre/6 days of grazing = 4.5 cows/acre
The size of the paddocks are affected by the size of the grazing herd, the frequency of rotations and the season of the year. Larger herds need larger paddocks. Larger paddocks relative to a given herd size require less frequent movement of animals, but will result in lower quality and greater waste of the forage. Because of the rapid growth of cool season grass species in Midwestern pastures, paddocks may be smaller in the spring or animals may be moved more rapidly. Extra forage may be mechanically removed. In the development of a controlled grazing system, the size of paddocks, stocking rate, animal behavior, watering system, milking system, reproductive management, and parasite controls need to be considered. To determine the size of paddocks, the length of the grazing and rest periods need to be considered. In a system with 5 and 30 day grazing and rest periods, the number of paddocks is calculated as:
Number of paddocks = (5 days of grazing+30 days of rest)/5 days of grazing = 7 paddocks
In a 70 acre pasture, the size of paddocks would be calculated as:
Paddock size = 70 acres per pasture/7 paddocks per pasture = 10 acres/paddock
If this pasture has a sward height of 10 inches and a 50% removal, the amount of available forage per paddock is calculated as:
Pounds of available forage/paddock = 10 inches x 200 lb forage per acre x 50% removal x 10 acres/paddock =10,000 pounds of available forage/paddock
If 1200 pound beef cows will graze this pasture, the stocking rate for this 10 acre paddock would be calculated as:
Number of cows/paddock = 10,000 pounds available forage per paddock/(5 days grazing x 1200 pounds x 3% body weight feed consumption) = 55 cows per pasture.
Because animals will graze in a circular motion, paddocks should be constructed to be as square as possible. Gates should be constructed to be highly visible. Water should be available in every paddock. In dairy operations, milking facilities should be centrally located. Either artificial or natural insemination may be used to breed animals in rotational grazing systems and may be more effective than in continuous grazing systems. Finally, parasite control is very important in an intensive grazing system because of the shorter forage. This videotape concluded with quotes from Ralph Neill and Rick Sprague on the improvements in harvest efficiency and profitability from rotational grazing systems.
The fourth videotape in the series is entitled “Managed Grazing: Fencing and Watering Systems” and was written by Ann M. Cowen, then an extension associate with the Southern Iowa CHIPS program in Ottumwa, Iowa and now a livestock technician at the Iowa State University McNay Outlying Research Farm. This videotape emphasizes the importance of advances in fencing technologies in the development of rotational grazing systems. The most significant improvement in fencing has been the low impedence electric fence energizer. These energizers are more effective because they provide greater current and, therefore, shocking power. The source of power for these energizers may be batteries, solar or from a main line power. In general, the main line powered energizers are preferred because of lower operation, maintenance, and purchase costs than other types of energizers. The size of energizer needed to fence a given pasture may be calculated by knowing that 1 joule of electric power will adequately serve 1 mile of fence. Furthermore, to ensure an adequate shock, 3 feet of grounding rod per joule of output from the energizer should be driven into the ground in a damp location at least 10 feet apart and solidly attached to the wire. To protect the system from lightning, lightning chokes and diverters should be placed in the system. In the fence, one wire should be used to manage mature cattle. Two wires are needed in a system holding calves. Three wires are needed to hold sheep. To prevent predators from entering paddocks holding sheep, 8 wires are required. High tensile wire is needed for perimeter fences. This wire should be 12.5 gauge and of good quality. Splices with high tensile wire requires twist links or crimping sleeves. Furthermore, tightening high tensile wire requires in-line strainers or a wire stretcher. Maxishock, polywire, polytape or electronet may be used for temporary or semipermanent fences. Polywire and polytapes are easily seen, but may break if overtightened. Maxishock is stronger, but is not as readily seen as polywire. Because of the danger of attachment to animals or humans, barbed wire should not be used with a low impedance energizer. Steel T-posts may be used with electric fence provided that good insulators are used. Fiberglass posts or sucker rods have the benefit of being nonconductive and, therefore, can be used with wire clips or cotter keys. Spring gates can be used in an electric fence, but may lose elasticity if subjected to excessive animal traffic. Polytape gates are less expensive and more visible than spring gates. Gates should be designed to be energized only when closed and should not be used to transfer power across the gate. In order to avoid soil erosion and uneven grazing associated with lanes and triangular paddocks, the watering system in a rotational grazing system should be designed with water in each paddock. Water may be delivered to the paddocks by pressurized, gravity flow or mechanical pump systems. The key to the water system is to have the waterer refill before the next animal drinks. Gravity flow systems need more capacity than pressurized systems because of slower refilling. Nose pumps may only be used in a frost-free environment. Water may be transported to the pasture by either above- or below-ground systems. Above-ground systems should be placed in the fence to provide protection and shade and must be drained in freezing weather. The water tanks should also be placed in the fenceline to prevent damage to the floats. This videotape is concluded with quotes from Mike Hunter and Rick Sprague discussing their experiences with watering systems.
The final videotape is entitled “Managed Grazing: Year Around Resource Management” and was written by James R. Russell from the Department of Animal Science at Iowa State University. This videotape emphasizes that because Midwestern farms have a variety of acres planted in row crops, small grains and hay as well as permanent pasture, the key to success in grazing-based animal production systems is to match: animal numbers, genetics and management with the types and amounts of forages available for grazing at different seasons of the year. Because feed costs comprise about half of the costs of producing livestock, optimal forage use during each season can increase economic returns. “Optimal forage use” means sustaining animal performance and minimizing the use of stored feeds while maintaining forage, soil and water resources. Because of slow growth and muddy conditions in early spring, producers may use sacrifice paddocks, stockpiled perennial forages or fall-seeded small grains to prevent premature grazing of summer pastures. In mid-to-late spring, forage growth will be rapid. Therefore, during this period, animals should be rapidly rotated and excess forage growth removed with extra animals or mechanical harvest. The slower growth rate occurring during midsummer requires slower rotation at 50% forage removal and removal of extra animals from the pasture. The adverse effects of midsummer conditions on forage growth may be minimized by the use of legume or warm season grass species. To manage the risk associated with drought, pastures should be stocked at a level that is 20% below the maximum of that pasture when rotationally grazed in a normal year. If production is further limited by drought, calves should be weaned and/or supplemental feeds should be offered. The rate of growth of cool season species in late summer will be directly related to the intensity with which these forages are grazed during midsummer. In the fall and winter, forages which are available for grazing include corn crop residues and stockpiled hay crop forages. Grazing of these forages may reduce feeding of stored hay by 1 to 1.5 ton per cow. Because grazing animals will select the most digestible portions of the plants, strip-grazing may extend the quality of the available forage. Weather losses of these forages can considerably reduce the nutritive value of these forages as well as large bales of hay. Therefore, supplementation of these forages with protein, phosphorus, trace mineral salt and Vitamin A may be required late in the grazing season, particularly for animals grazing corn crop residues. In late winter, animals may be moved to drylots or sacrificial pastures to limit damage to forage plants and soil tilth. After discussing the forages that are available for grazing at different seasons of the year in the Midwest, integration of the animals’ nutrient needs with forage availability was addressed. The energy requirements of beef cows are affected by mature size, milk production potential, body condition, pregnancy and physical environment. It is essential to maintain a body condition score of 5 on a 9 point scale at the beginning of the breeding season to promote rebreeding. This means that cows with a moderate size and milk production potential might be the most profitable types to use in a year-round grazing system. Furthermore, because maximum energy needs for milk production occur 6 to 8 weeks after calving, energy requirements of beef cows match forage availability best if calving occurs in April. It is difficult, however, to finish cattle at a season high. In contrast, calving in May shifts energy requirements so that they are lowest when forage availability is lowest. Therefore, May calving provides the opportunity to winter cows entirely on grazed forages. In contrast, maximum energy requirements of cows occur after peak forage availability, the breeding season occurs when forage availability may be limited and fed cattle are sold at lower summer prices. Similar to beef cows, nutrient requirements of dairy cows are affected by cow size, production level, growth, and pregnancy. Cow size and milk production potential should match forage resources. On farms with highly erodible soils, seasonal dairying with a small cow with moderate milking ability is likely most profitable. Whereas, on farms with land which can be tilled, managing for high milk production with maximum grazing from April to December is likely to be more profitable. Also like beef cows, animal nutrient requirements will match forage availability by calving in April. In spite of good management, greater variability in quantity and quality of the forage supply is more likely to occur in a grazing system than in a confinement system. As a result, supplementation of grazed forage may be necessary. Supplementation rules include: feeding grain at 1 lb for every 3.5 to 4 lbs of milk production; feeding a protein source with a low ruminal degradability; feeding small amounts of hay; and not feeding supplemental fat. Grazing of forages may reduce the amount of grain needed to finish steers by 15 to 45%. In this system, winter feed costs should be minimized by grazing corn crop residues or stockpiled hay crop forages during winter. In the spring and summer, grazing should be managed to maximize weight gains. If weight gains drop below 2 lb/day, the animal should be moved to a feedlot for finishing. Although supplementation of pastures with grain is not recommended, supplementation with small amounts of a protein source with a low ruminal degradability may increase weight gains in stocker steers. Like cattle, the nutrient requirements of ewes is affected by size, pregnancy, and milk production. Peak energy requirements occur 4 weeks after lambing and at the initiation of the breeding season. While traditional February lambing is not synchronous with forage availability, late April or early May lambing results in the peak energy requirements occurring when forage availability is highest. Although predators and parasites might be problems with pasture lambing, these problems may be minimized through management. This videotape ends with the statement that “It is essential for each producer to look at his or her operation when planning and adapting an intensively controlled grazing system. The key to optimum profits is to match the numbers, genetics and management of animals with the forages available for grazing in every season of the year.”
Pasture Management Guide for Livestock Producers
In the introduction to the Pasture Management Guide for Livestock Producers, Stephen Barnhart stated that “Despite Iowa’s soil wealth, about one-third of Iowa’s land is highly erosive and unsuited for continuous row-crop production. Pastures can be a way to diversify production enterprises, improve returns, and spread risk – and usually with a relatively low capital investment. This publication provides an overview of pasture management: practices to increase production and returns by improving management on our grassland acres.” The introduction continues that “Good pasture management is not simple. It involves managing the interrelationships among animals, plants, and soil. The manager’s role, then, takes on great importance in pasture management. The manager in fact is the key to good pasture management. Pasture management is largely individualized. The manager must determine the best way to balance changing components related to specific pastures and animals with the manager’s chosen level of management. As you consider making pasture management changes, don’t set unrealistic production goals.” The remainder of the book is divided into 5 chapters enlarging on different topics on grazing and livestock management.
Chapter 1, “Managing pasture plants,” prepared by Stephen Barnhart, Kenneth Moore, and E. Charles Brummer, first discusses pasture plants from the point of view on managing pasture plants in old, long-term pastures or new pasture such as carryover hay fields. The advantages and limitations of different species for incorporation into pastures is shown in tables as well as text on new and improved plants for pasture use. To provide a basis for grazing management, the growth and development of forage plants and the relationship between forage quality and grazing animal performance are discussed. To provide a technical background for improvement of existing pastures, different approaches to weed and brush control, guidelines for pasture fertilization and other pasture maintenance practices are covered. Finally, approaches to renovating existing pastures or establishing new pastures are discussed.
Chapter 2, “Livestock Management,” was written by James Russell, Daniel Morrical, Stephen Barnhart, and Peggy Miller. This chapter begins with a discussion of the nutrient requirements of breeding and lactating beef cattle and sheep, dairy cattle, stocker and growing cattle, and horses. The text continues into health problems associated with grazing including: grass tetany, prussic acid poisoning, nitrate poisoning, poisonous plants, bloat, parasites, pink eye, and fescue toxicosis. The next section of this chapter defines pasture and grazing systems including continuous grazing, rotational grazing, management intensive grazing, and strip-grazing, describing the advantages and limitations of each approach. Subsequently, topics related to understanding the behavior of grazing animals and using this in their management was discussed. Topics covered included: daily grazing behavior, herd effects, managing horses, animal grazing efficiency, over- and pattern-grazing, grouping animals by nutrient needs, reproduction, training to electric fences, medication and routine handling, shade, and watering systems. Considerations in pasture management during periods of drought or excessive precipitation are described. Finally to provide the basis for integrating grazing animal nutrition with the availability of forages throughout the year, discussions of forages availability for grazing at different seasons of the year, the adjustment of animal nutrient requirements through varying production cycles and the appropriate use of supplement feed resources are discussed.
Chapter 3, entitled “Planning for Improvements in Grazing Systems,” written by Daniel Morrical, James Russell, and Stephen Barnhart, discusses the steps of laying out a rotational grazing system. This chapter begins with discussing the goals of your grazing system including the relative animal response that one could expect from different levels of management and the recommended number of paddocks. This section is followed by a discussion of how to calculate and utilize animal unit months as a pasture management planning tool. The following section describes how pasture productivity can be utilized to estimate the productivity and carrying capacity of individual pastures. Similar to the videotape series, there is a description and example of how paddock size and number may be calculated and the proper approach to laying out a rotational grazing system. Included here is a list of the does and don’ts of a electric fence system. Finally, there is an example of how a rotational grazing system of increasing complexity could be implemented on a given farm over a number of years.
Chapter 4, “Monitoring and Evaluating the Grazing System,” written Daniel Morrical and Stephen Barnhart, discusses the importance of records and the methods by which they may be measured and recorded. In the first section of this chapter, it is emphasize that records are needed to record “as it really was” information to evaluate and revise the grazing program. But the records do not have to be complicated. Animal performance records that can be recorded include birth dates, breeding dates, calving and lambing dates, reproductive efficiency and performance of individual animals. Pasture productivity may be estimated by the grazing days per acre, measuring forage heights or estimating forage quantity. Because pasture costs determine net profitability there is a discussion on how this may be determined and utilized to make management decisions.
The last chapter, “Managing Risk in Grazing Systems,” written by Stephen Barnhart, discusses the use of a continuous grazing system, a 4-paddock rotational grazing system or a 12-paddock management intensive grazing system by individual who are risk adverse or who are willing to accept risks.
The appendices of the book have a summary of pasture and grazing terms, pasture worksheets and selected references and resources on grazing.
Because of the greater forage production associated with rotational grazing systems, stocking rates may be increased by 40% over continuous grazing without adversely affecting individual animal performance. By extending the grazing season by the use of grazing corn crop residues or stockpiled hay crop forages will reduce stored feed used while leaving excess hay available for sale. Using a spreadsheet to compare systems in research funded by the Leopold Center for Sustainable Agriculture at Iowa State University, it was found that the net returns would be $89.90 per beef cow from a system combining summer rotational grazing and winter stockpiled forage grazing to net returns of $29.74 per beef cow from a system utilizing continuous grazing during summer and feeding of hay in a drylot during winter. Because the size of the average cow herd in Iowa is 36 cows, utilizing an intensively managed grazing system would increase net income of farms by $2,165 at equal stocking rates compared to operations with less intensive grazing management and $3,032 if the producers used the greater efficiency to increase stocking rates. Furthermore, since there are approximately 33,000 cow-calf farms in Iowa, incorporation of improved grazing practices would increase farm income in Iowa alone by $50 million per year if 50% of the producers incorporated improved grazing practices on their farm. Because livestock production has a multiplier effect on the entire economy of Iowa of nearly $6 for each $1 of net income if 50% of the producers in Iowa would incorporate improved grazing practices, the increase in Iowa’s economy alone would be $300 million. This increase could be repeated in other midwestern states, since the incorporation of improved grazing practices in the Midwest with its more productive soils and timely precipitation should improve the competitive advantage of midwestern farms.
Furthermore, because the Iowa State University Beef Cow Business Records have shown a difference of $231.40 in net profit per cow between high profit and low profit operations in Iowa and since most of this difference relates to differences in feed costs, the improvements in returns resulting from improved grazing practices may even be greater than estimated from our research results.
Similarly, incorporation of grazing into dairy operations should significantly improve net returns from these enterprises. USDA research has shown that grazing of dairy cattle will increase net returns by $101 per acre compared to confinement management. Because 625,000 acres of land in Iowa are used for dairy production, an increase in net returns of $6.6 million from dairy production in Iowa may be expected if even 10% of the dairy farms utilized management intensive grazing to a significant extent.
The improved returns resulting from intensive grazing management should provide the incentive for producers to maintain forages on highly erodible lands. Because the difference in soil erosion between the production of row crops and forages on highly erodible lands is 10.3 tons/acre/year, maintaining them in forages should significantly reduce this source of pollution.
In a survey of county extension offices in Iowa in 1996, it was found that the 1 or more of the videotapes in the series had been signed out by 0 to 14 individuals. This means that at least 700 individuals had seen the videotapes. However, since it is likely that some of the individuals who took out the tapes used them for educational purposes, the number of people who actually saw the tape may have been 5 to 10 times greater. Furthermore, the tape series has been sold to 410 individuals across the country and, many of these individuals are educators and extension personnel, it has been seen by many other individuals in the country. An evaluation of the videotape series sent to purchasers in 1996 is included in Appendix B.
Involvement of Other Audiences
In such a complex project as preparing a videotape and a book on improved grazing practices, considerable cooperation is needed between institutions and cooperators. Research personnel from Iowa State University included Jim Russell, Ken Moore and E. Charles Brummer. Extension personnel with considerable involvement in the project included Dan Morrical, Steve Barnhart, Peggy Miller, Ann Cowen and the personnel from the Extension Communications Department. Also technical assistance in the preparation of the book was provided by the Ames Laboratory Communications Department. Bob Dayton and Rick Sprague from the USDA-Natural Resources Conservation Service made substantial contributions in the preparation of the videotape. Finally, the project would have been impossible without the assistance of the cooperating farmers including Ralph Neill, Steve Hopkins, Jed Becker, Mike Hunter, and Don Faidley. These farmers not only provided their facilities for videotaping, but also gave quotes that assisted in providing legitimacy to the series. In addition, Ralph Neill also flew his plane so that we could obtain aerial shots of his farm and the Corning CRP Grazing Demonstration Farm.
Educational & Outreach Activities
The major outcome of this project was the development of the 5-tape videotape series entitled “Managed Grazing” (See Appendix A). This series was completed in October, 1995 and distributed to each county extension office in the state of Iowa. To promote sales of this series, a press release was prepared and distributed in newspapers throughout Iowa, magazines and on electronic bulletion boards like forage-mg, beef-L and dairy-L. As a result of this publicity, 410 copies of the videotapes have been sold.
To supplement the videotape series, a book entitled “Pasture Management Guide for Livestock Producers” was prepared and completed in June, 1998. This book will be distributed to each area livestock extension specialist and cropping extension specialist in Iowa. Furthermore, a announcement will be prepared for distribution to videotape purchasers, state extension beef, dairy and forage specialists, popular press and computer bulletin boards.
Areas needing additional study
Although this wasn’t a research project, attempting to develop recommendations for year round grazing systems revealed areas in which information is lacking. First, these is relatively little known about the best forage species and management practices for grazing in late winter to minimize production costs associated with stored feeds. Not only does animal production need to be studied, but also the effects of winter grazing on subsequent plant growth and soil compaction need to be considered. Furthermore, because it is apparent that grazing management in early spring affects seasonal productivity of summer pastures, the optimum conditions at which to initiate grazing of summer pastures need to be identified. Much, if not all of past grazing research has began after growth was adequate in late April or early May. Such an approach does not address the situation on a farm when under wet, muddy conditions the farmer must ask, “Can I begin grazing without adversely affecting seasonal forage production?”
In regards to animal production systems, there is the need for economic analysis of changing the calving date to better match feed resources. While we can readily say that moving the calving date to April and May will better match nutrient requirements and result in lower feed costs than the traditional February calving, this system could result in calves being lighter at a comparable weaning date and reaching finishing weights later in the year. Thus, the forage-based beef cow-calf system must be integrated with different systems of managing and finishing calves. Furthermore, supplementation regimes to optimize the productivity of different animals species from grazing systems need to be studied and identified.
In regards to future educational needs, consideration in the future should be given to supporting more videotape productions. Although animals have grazed for centuries and grazing research has been conducted in southern and western states as well as in other countries, it has only been in the last decade that detailed research on intensive grazing management has been conducted in the upper Midwest with its particular soil and environmental conditions.
Furthermore, much of the grazing research reported in the literature has been conducted over discrete time intervals with little consideration of how it related to animal production over the entire year or the entire farm operation. Only in recent years have forage-based livestock production systems been considered from a year-round whole farm basis. As information is developed from these studies, opportunities for developing further videotapes on the economic and technical considerations of integrated livestock/crop production systems will evolve and should be funded.