382 - XXX

NATURAL RESOURCES CONSERVATION SERVICE

CONSERVATION PRACTICE STANDARD

FENCE

(Ft.)

Code 382

NRCS, NHCP

April 2007

382 - 3

DEFINITION

A constructed barrier to animals or people.

PURPOSE

This practice facilitates the accomplishment of conservation objectives by providing a means to control movement of animals and people, including vehicles.

CONDITIONS WHERE PRACTICE APPLIES

This practice may be applied on any area where management of animal or human movement is needed.

CRITERIA

General Criteria Applicable to All Purposes

Fencing materials, type and design of fence installed shall be of a high quality and durability. The type and design of fence installed will meet the management objectives and site challenges. Based on need, fences may be permanent, portable, or temporary.

Fences shall be positioned to facilitate management requirements. Ingress/egress features such as gates and cattle guards shall be planned. The fence design and installation should have the life expectancy appropriate for management objectives and shall follow all federal, state and local laws and regulations.

Height, size, spacing and type of materials used will provide the desired control, life expectancy, and management of animals and people of concern.

Table 1 shows criteria for selecting fence types based on intended use, number of wires and height. Appendix 1 includes material and installation specifications for materials and installation.

CONSIDERATIONS

The fence design and location should consider: topography, soil properties, livestock management and safety, livestock trailing, wildlife class and movement, location and adequacy of water facilities, development of potential grazing systems, human access and safety, landscape aesthetics, erosion problems, moisture conditions, flooding potential, stream crossings, and durability of materials. When appropriate, natural barriers should be utilized instead of fencing.

Locate fences (division fences) to help facilitate management of different landuses and special management areas within landuses such as ecological sites, pasture types, riparian areas, critical eroding areas, etc.

For domestic livestock, install fences in areas that will best facilitate the handling, feeding, watering and movement of the type of livestock managed. Consider fencing along the contour to minimize livestock trailing and subsequent erosion.

When installing interior fences to facilitate livestock movement (cross fencing), temporary fences should be considered in order to minimize costs and allow for flexibility in the system. Locations should allow for the shortest and straightest distances.

For horses, consider avoiding the use of barbed wire when possible in order to minimize potential injury, especially when areas of confinement are small.

When installing fences in areas of heavy wildlife movement / traffic (such as riparian areas) consideration should be given to wire types and spacing. Spacing of top and bottom wires should be adequate for the movement of the types of wildlife managed for. Where barbed wire is used, the cooperator should consider smooth wire for the top and bottom wires to reduce potential for harm to deer jumping over fence.

When planning and installing fences in areas of known prairie chicken habitat, consider using approved marking methods to help prevent bird collisions and minimize mortality. Guidance for fence marking can be found at www.suttoncenter.org.

Where applicable, cleared rights-of-way may be established which would facilitate fence construction and maintenance. Avoid clearing of vegetation during the nesting season for migratory birds.

Fences across gullies, canyons or streams may require special bracing, designs or approaches.

Fence design and location should consider ease of access for construction, repair and maintenance. Where practical, in order to minimize maintenance and installation costs, avoid areas such as rough and irregular terrain, excess trees and brush, areas with long-standing water and water crossings

Fence construction requiring the removal of existing unusable fence should provide for the proper disposal of scrap materials to prevent harm to animals, people and equipment.

FENCE TYPES

The overall effectiveness of each type of fence and the costs for installation and maintenance, depends on type of animal controlled, the number and size of wires used, posts type and spacing.

Standard Post and Wire Fences are the most common fence type used for controlling all types of livestock. They are suitable as permanent fences in areas that receive moderate to heavy pressure from livestock. They are typically barbed wire or double strand smooth wire.

Permanent Energized (Electric) Fences provide a low cost alternative and more flexibility to the other types of fences. They are mostly used for interior cross fencing but can also be used for boundary fences. They can be powered by a variety of types of energizers. Livestock must be trained to respect electric fences if they are to be effective.

Suspension Fences are a low cost variation of the standard post and wire fence and can be used as either boundary or interior cross fencing. They are typically used on large pastures with level terrain. They can be either barbed wire or smooth wire. The fence design allows it to sway (move) in the wind and when contacted by animals.

Woven, Net and Mesh Wire Fences are best suited in areas where tight control is necessary such as with sheep, goats, horses, hogs, people or predator control. These fences consist of multiple rows of horizontal smooth wires held apart by vertical wires, usually of different sizes and configurations. Space between wires varies depending on designated use.

Temporary Electric Fences are only used for interior cross fencing, areas needing temporary protection / exclusion (i.e. during vegetation establishement) and areas where pressure from livestock is not heavy. They can be easily attached to permanent fences and can be of either high tensile smooth wire, net fencing (for use with sheep and goats), polyethylene twine and/or tape.

High Tensile, non-energized fences are suitable as permanent fence in areas that receive moderate to heavy pressure from livestock but require more strands of wire than barbed wire to maintain the same level of control. These fences are safer for domestic animals, especially horses, and wildlife than are the barbed wire fences

Other Fence Types include chain link, pipe, vinyl, galvanized panel, board and cable fences. These fences are generally more expensive to install and maintain. They are generally used around corrals and homesteads. They may be used to restrict access to unsafe areas such as lagoons, abandoned mines and other unsafe or sensitive areas. When used for livestock control, they will be designed based on type of animal controlled.

PLANS AND SPECIFICATIONS

Plans and specifications are to be prepared for all fence types, installations and specific sites. Requirements for applying the practice to achieve all of its intended purposes shall be described.

OPERATION AND MAINTENANCE

Regular inspection of fences should be part of an ongoing maintenance program. Inspection of fences after storms and other disturbance events is necessary to insure the continued proper function of the fence. Maintenance and repairs will be performed in a timely manner as needed, including tree/limb removal and water gap replacement.

Remove and properly discard all broken fencing material and hardware. All necessary precautions should be taken to ensure the safety of construction and maintenance crews.

References

Bell, H.M. 1973. Rangeland management for livestock production. University of Oklahoma Press.

Heady, H.F. and R.D. Child. 1994. Rangeland ecology and management. Western Press.

Holechek, J.L., R.D. Pieper, and C.H. Herbel. 2001. Range management: principles and practices. Prentice Hall.

Stoddard, L.A., A.D. Smith, and T.W. Box. 1975. Range management. McGraw-Hill Book Company.

United States Department of Interior, Bureau of Land Management and United States Department of Agriculture, Forest Service. 1988. Fences. Missoula Technology and Development Center.

United States Department of Agriculture, Natural Resources Conservation Service. 2005. Electric fencing for serious graziers. Columbia, Mo.

United States Department of Agriculture, Natural Resources Conservation Service. 2003. National range and pasture handbook, revision 1. Washington, DC.

Vallentine, J.F. 1971. Range development and improvement. Brigham Young University Press.

Planning Fences, American Association for Vocational Instructional Materials, Third printing, 1997

Building Fences, American Association for Vocational Instructional Materials, 1974

Fence Brace Assemblies, Circular 792, Institute of Food and Agricultural Sciences, Rev. 1992

ASTM STANDARDS 116,121

Fences, USDA Forestry Service Handbook, Feb. 1999

NRCS, OK

March 2009

382 - 3

Intended Use / Fence Type / Minimum Number of Wires / Average Height
Top Wire1 / Max Line Post Spacing
W/O Stays1 / Max Line Post Spacing W/ 2 or more Stays
Cattle
/ Standard Barbed Wire / 3 / 38-42 / 20 / 30
4 / 44-48
5 / 48-52
Suspension / 4 / 44-48 / N/A / 1003
Smooth, high tensile, non-energized;
Double strand, non-barbed / 5 / 48-52 / 20 / 30
Smooth, high tensile, Energized / 3 / 38-42 / 75 / 150
4 / 44-48
Woven Wire (Addition of 1-2 barbed wires may be added to achieve total height) / NA / 42-48 / N/A / N/A
Goats / Sheep
/ Woven Wire (Caution with horned goats) / NA / 32-42 / N/A / N/A
Standard Barbed Wire / 7 / 38-42 / 15 / 20
Smooth, high tensile, non-energized;
Double strand, non-barbed / 7 / 38-42 / 15 / 20
Smooth, high tensile, Energized / 5 / 34-38 / 75 / 150
Horses
/ Board / NA / 48 / N/A / N/A
Woven, Mesh / NA / 42-48 / N/A / N/A
Standard Barbed Wire / 4 / 48-52 / 20 / 30
Smooth, high tensile, Energized / 4 / 48-52 / 75 / 150
Smooth, high tensile, non-energized ;
Double strand, non-barbed / 5 / 52-56 / 20 / 30
Large Wildlife / Woven / NA / 96 / N/A / N/A
All
Livestock / Temporary (portable), Energized2 / 1-3 / 2/3 shoulder height of animal / N/A / N/A

Table 1: Minimum criteria for selection and installation of fences. Fence design and construction must meet or exceed these criteria.

1.  Exception is for all property boundary fences, which shall be a minimum of 54 inches for all fence types. Spacing may need to be narrower depending on terrain and pressure from livestock. Lanes, holding pens, areas around watering and feeding facilities as well as property boundaries will have a maximum spacing of 16 ½ feet.

2.  Temporary / Portable fences are only used for interior crossfencing or for temporary protection of areas (i.e. critical area during vegetation establishment). Should not be used for areas that will receive heavy livestock pressure. May be smooth high tensile steel, aluminum, galvanized, polywire or polytape (See Table 2 for wire requirements)

3.  Stays will be installed at no more than 15 foot intervals between posts. They should swing free of the ground to permit the fence to sway. Stays will be constructed of durable materials designed for this purpose.

NRCS, OK

March 2009

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APPENDIX 1: MATERIALS and CONSTRUCTION SPECIFICATIONS

Variations from materials and construction may be approved if sufficient documentation is provided to the State Resource Conservationist that proves the variations will result in an installation that will meet or exceed this standard and specification

I  WIRE

All wire will be of new galvanized material and in accordance with criteria outlined in Table 2 which follows American Society of Testing Materials (ASTM) standards.

Table 2 Minimum Criteria and Specifications for Wire

Wire Type / Minimum Wire Size / 1/ Other Requirements (Protective coatings, Tensile Strength / Breaking Load) etc.
Standard Double Strand Barbed wire
Standard Smooth double strand wire / 12 1/2 gauge
(Barbed will have 14 gauge or heavier two-point barbs spaced 4-6 inches apart.) / Class I galvanized. Meets ASTM-121
70,000 psi / 950 lbs. breaking load
Standard Smooth single strand / 9 gauge / Class I galvanized. Meets ASTM-121
70,000 psi / 950 lbs. breaking load
High-Tensile Double Strand Barbed Wire / 13 ½ - 15 ½ gauge / Class III galvanized. Meets ASTM-A854. Heat treated High Tensile. 170,000 psi
High Tensile Smooth single strand / 12-1/2 gauge
Standard Woven Wire / Top & Bottom wires: min. 11 gauge
Intermediate & Stay Wires: min. 14-1/2 gauge / Class I zinc coating or equivalent. Meets ASTM 116. 32 -48 inches minimum height; Maximum 12 inch spacing between stay wires.
High Tensile Woven Wire / 14 1/2 gauge / Class III zinc coating or equivalent. Meets ASTM 116. 32 inches minimum height ; Maximum 12 inch spacing between stay wires.
Mesh Wire; such as Horse-No-Climb / Top & Bottom wires: 10 gauge
Intermediate & Stay Wires: 12-1/2 gauge / Class I zinc coating or equivalent. At least 48 inch high, less than or equal to 2 inch x 4-inch mesh spacing.
Polywire or “ Twine-Type “ / Minimum of 8 strands of aluminum or stainless steel filaments / Wires interwoven with polyethylene or polypropylene fiber. Only used for temporary fences and where pressure from livestock is not heavy.
The polywire (twine-type) is more durable especially when it is being rolled up and moved often and should be used when multiple wires are planned.
Polytape (tape-type) is best used in situations where high visibility is a concern such as with horses.
Polytape or “Tape-Type” / Minimum ½ inch wide and 5 strands of aluminum or stainless steel filaments
Galvanized Steel / 14 gage / Use for 1 to 2 wire temporary fences.
150,000 psi / 690 lbs. breaking load
Aluminum / Use for 1 to 2 wire temporary fences.
38,000 psi / 215 lbs. breaking load

1/ Wires designated as regular, commercial and utility grade wires are available but do not offer the level of treatment as the Class I and III. Cooperators should be informed of this fact when considering wire. These types are not included in this standard. Most wire manufacturers include wire specifications on fence tags. If information is not provided or known, lab testing may be needed to determine strength of wire.

NRCS, OK

March 2009

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WIRE SPACING

Height of the top wire will be as specified in Table 1. Fences for large animals like cattle will have the bottom wire a minimum of 12 inches from ground and no more than 16 inches. The top wire will be based on intended use (Table 1.). All other wires should be equally spaced. For smaller animals like sheep and/or goats, the bottom wire shall be no more than 5-6 inches up from the ground and maximum spacing between lower wires (lower 18-20 inches of fence) will be 8 inches. When there is a combination of livestock, such as cattle and sheep, the lower wires shall be designed for the smaller animal and overall height will be for the larger animal.