Farm Fencing for Australian Properties

Fencing is the infrastructure decision with the longest time horizon on any small farm. A post and wire fence correctly built with quality materials will last thirty to fifty years with normal maintenance. One built to a lower standard — undersize posts, inadequately galvanised wire, cut-price droppers, under-strained wires — will begin failing within five to fifteen years, requiring expensive repairs at inconvenient times, and will never perform as well in the meantime. The cost difference between a good fence and a poor one is typically 20 to 35% at installation; the difference in total cost of ownership over thirty years strongly favours the quality fence.

This is not an argument for the most expensive fence in every situation. It is an argument for matching the fence to the task and building that fence properly. A permanent boundary fence carrying high stock pressure — containing cattle on a boundary with a neighbour, or providing the outer perimeter of a rotational grazing system — deserves quality materials and careful construction. A temporary internal subdivision fence used for rotational grazing management that will be relocated in three to five years as the system evolves is appropriately a lower-specification electric fence. Getting this matching right — permanent where permanence is justified, flexible where flexibility is needed — is the key to cost-effective fencing across a whole property.

The most expensive fencing mistake on Australian small farms is not poor materials — it is inadequate strainer assemblies. The strainer post is the anchor from which all fence tension derives. An under-strained fence sags in the centre of each bay, animals push through it, and within a few months it has failed to contain stock, become a source of ongoing repair work, and depreciated its materials value rapidly. Strainer posts that are correctly sized, correctly set in the ground, and correctly stayed or box-braced are the foundation that makes everything else in the fence work. Skimping on strainers and putting money into the wire instead is building on sand.

The boundary fence is the most important fence on the property — it is the last line of defence against stock escaping onto roads or neighbouring properties, and it must reliably contain every class of livestock you run. The appropriate specification depends on your main livestock species, your terrain, and the nature of the boundary (road, watercourse, neighbour with compatible or incompatible fencing).

Ringlock (hinge joint) mesh fencing is the most widely used and most versatile boundary fence type in Australia. The hinge-joint wire pattern — individual horizontal wires connected to vertical stays by a double wrap — creates a flexible mesh that deforms rather than breaks under impact, making it more durable than fixed-knot alternatives in situations where large animals (cattle, horses, kangaroos) apply shock loads. Standard specifications for mixed livestock boundary fencing: 1.05 to 1.2 metre height mesh (typically 11 or 13 line wire configurations), 2.5mm minimum galvanised wire, with one to two plain or barbed wire strands above the mesh on steel posts at 2.5 to 3.5 metre spacings, with a bottom wire clipped or tied to the mesh to prevent animals lifting it.

Plain and barbed wire fencing with steel or timber posts is appropriate where the livestock being contained respond adequately to wire (cattle in particular) and where the terrain makes mesh fencing impractical or uneconomic. Five-wire plain wire or six-wire barbed configurations on steel star pickets at 3 to 4 metre spacings are common for cattle country fencing across inland Australia. Wire gauge matters significantly for longevity — 2.5mm (200 class) high-tensile wire is substantially more durable than the 2.0mm wire used in cheaper fencing products. High-tensile wire can be run at higher tension than soft wire, reducing sag between posts and allowing wider post spacings, but it requires tensioning equipment and care in handling.

Post specifications are where many producers make cost-saving decisions that prove expensive over time. Corner and strainer posts must be sized for the job: minimum 200mm diameter timber (cypress pine, treated hardwood, or steel equivalent) for standard agricultural fencing, increasing to 250mm for high-tension or long-run applications. Set timber strainer posts at a minimum of 900mm depth in firm ground, 1.1 to 1.2 metres in soft or sandy soils. Steel strainer posts should comply with manufacturer specification for the application. Line posts (intermediate posts between strainers) can be lighter — star pickets are adequate for most agricultural applications and represent the lowest-cost compliant option for internal spacing. The rule is: strainers heavy, line posts practical.

Galvanisation is the primary determinant of wire fence longevity in Australian conditions. Galvanising is the zinc coating applied to steel wire to prevent corrosion — the thicker the coating (measured in grams of zinc per square metre of wire surface, expressed as Class 1, 2, or 3 on Australian products), the longer the wire lasts before rusting. Class 3 galvanised wire has approximately three times the zinc coating of Class 1 and will last significantly longer in most conditions. In coastal, high-humidity, or salt-air environments, the difference in longevity between Class 1 and Class 3 wire is even more pronounced. Always buy Class 3 (sometimes labelled C3 or Z275 or equivalent) for any permanent fence investment — the price premium is modest and the longevity gain is substantial.

Road frontage fencing carries specific obligations in most Australian jurisdictions — stock that escape onto public roads create a liability for the property owner in the event of an accident. Road frontage fences should meet the highest specification you apply to any boundary fence, should be inspected more frequently, and should be repaired immediately when a fault is identified. In some states, road frontage fencing specifications are prescribed in legislation — check your state's Dividing Fences Act and relevant roads authority guidelines for your specific obligations.

Electric fencing is the most cost-effective and flexible fencing system available for internal subdivision and for many small farm boundary applications. A well-designed, well-charged electric fence containing trained animals is as reliable as permanent wire fencing at a fraction of the capital cost. The critical phrase is "well-charged containing trained animals" — the failures of electric fencing almost always result from one or both of these conditions not being met.

The energiser (commonly called a "fencer" or "electric fence unit") is the heart of the system. Energiser selection should be based on two factors: fence length and the primary livestock to be contained. Energiser output is measured in joules of stored energy — a higher joule rating drives voltage further down a longer fence line and maintains adequate shock through contact resistance from vegetation and wet soil. As a rough guide: 1 joule per 10 kilometres of single-strand fence for sheep and goats (which require a minimum 3,000 volts on the fence to respond reliably); scale up for multiple strands, longer runs, or cattle (which can tolerate higher voltage but respond to lower). Always buy a larger energiser than your minimum calculation suggests — a fence operating at comfortable margins above the minimum voltage is far more reliable than one working at its limit, and energiser capacity is inexpensive relative to the fence infrastructure it protects.

The earth system is the most commonly underdone component of Australian electric fence installations and the most common cause of poor performance. The energiser completes its circuit through the soil — the animal touches the live wire and completes the circuit back through the ground to the earth stakes. If the earth stakes are inadequate (too few, too short, in dry soil), the return circuit is poor and the shock is dramatically reduced regardless of what the energiser is producing. Minimum earth system: three earth stakes at 1.2 to 1.5 metres length, galvanised or stainless steel, driven fully into soil, spaced 3 metres apart, all connected in series with the energiser earth terminal. In dry conditions or sandy soils, water the earth stake area regularly, add more stakes, or consider a return-wire (pig and goat) earth system where alternating fence wires are live and earthed, which does not depend on soil conductivity for the return circuit.

Voltage on the fence, under load, should be checked regularly with a digital voltmeter rather than estimated from the energiser rating. A fence that reads 5,000 volts on an unloaded test may read only 1,500 volts when vegetation is touching it and the earth is dry — well below the effective threshold. Check voltage at the far end of the fence from the energiser, not at the source, as voltage drop along the fence line can be substantial. When voltage is inadequate, the diagnostic sequence is: check energiser output (disconnect all fence wires and check voltage at the terminal — this tells you whether the problem is the energiser or the fence); walk the fence checking for shorts (vegetation contact, broken insulators, wire touching the post); check earth system. In most cases, vegetation shorts on the fence wire are the primary cause of voltage problems and can be managed by slashing the fence line after installation.

Training animals to respect electric fencing is essential — an untrained animal that has never encountered hot wire will simply run through it, often at high speed, which may injure the animal and will certainly damage the fence. The standard approach: construct a training paddock or lane with a single hot wire at appropriate height for the species (nose height — sheep approximately 500mm, cattle approximately 700mm, goats approximately 400 to 600mm); bait the wire with molasses or similar to encourage animals to touch it on purpose; allow them to self-educate against a well-charged fence. Most animals learn in a single session. Once trained, they will respect hot wire reliably, and a trained animal will not test a temporarily un-energised fence for extended periods because its learned avoidance behaviour is ingrained.

Temporary electric fencing — reels of polywire or polytape, fibre glass or aluminium step-in posts, and a portable energiser — is the most flexible tool for rotational grazing management on small farms. A single person can establish a temporary subdivision fence across a 5-hectare paddock in thirty minutes, move stock, and relocate the fence again in a week as the rotation advances. The capital cost is minimal; the flexibility is enormous. Polywire (multifilament wire with interwoven conductive strands) is more durable than polytape in UV-exposed situations and handles tension changes better. Replace polywire when the conductive strands break down and resistance increases — this typically occurs after three to five years of continuous outdoor use.

The strainer assembly — corner post, end post, and their associated stays or box-bracing — is the component on which all fence tension depends and the one that most commonly fails in poorly built fences. Every wire in the fence between two strainers is in tension, and that tension is entirely borne by the strainer assemblies at each end. If those assemblies are inadequate, the fence sags, animals push through, and repeated re-tensioning is required until the strainer fails completely.

A correctly built corner assembly for standard agricultural fencing consists of: a strainer post of at least 200mm diameter (125mm for steel H-brace assemblies), set at a minimum 900mm depth and ideally 1.1 metres; a horizontal brace rail running from the strainer post to an adjacent brace post (typically 1.8 to 2.1 metres away) at approximately two-thirds the finished fence height; and a diagonal stay wire running from the base of the strainer post to the top of the brace post, tensioned with a twitch or turnbuckle. This configuration — the box strainer assembly — transfers the horizontal tension of the fence wires downward into the ground through the diagonal wire, rather than pulling the strainer post forward and out of the ground.

For long fence runs (over 400 to 500 metres between strainers), inline strainer assemblies should be placed at intervals to prevent cumulative tension from sagging the fence between anchor points. An inline strainer (or "ringing post") uses the same principle as a corner assembly but is positioned in line with the fence rather than at a change of direction. On undulating terrain, strainer assemblies are also required at significant changes in grade — uphill or downhill runs exert different tension forces than level ground, and changes in grade without intermediate strainers allow the fence to develop a characteristic uphill or downhill droop.

Setting strainer posts correctly requires: a hole of adequate depth and diameter (wider at the base than the top for improved pull-out resistance in sandy soils); adequate backfill compaction (tamped in 100mm layers, not just shovelled in); and time for the post to settle before tensioning. Strainer posts should ideally be set at least a week before the fence wires are tensioned — a newly set post in soft ground that is immediately tensioned will often move as the soil settles around it. Where soil conditions are very soft (recent fill, alluvial silt, poorly drained clay), concrete encasing the base of strainer posts significantly improves performance and should be considered the standard rather than the exception.

The containment requirements differ significantly between livestock species, and a fence adequate for one species may be completely inadequate for another. Understanding these differences before installing new fencing prevents the frustrating and expensive experience of building a fence that works for cattle but fails completely when goats are introduced, or vice versa.

Cattle fencing is the most forgiving of the common livestock fencing situations. Cattle respect plain wire at adequate height and tension, and a five-wire plain wire fence (or three to four wires above a lower ringlock mesh) will contain cattle reliably with minimal maintenance. Electric fencing works extremely well for cattle — a single strand of hot wire at 800 to 900mm height is sufficient to hold trained cattle in most situations. The main failure modes for cattle fencing are: wire broken or post knocked by bull or large animal in rut or agitation; creek crossing points where stock repeatedly access water (these points experience concentrated traffic and need heavier construction and more frequent inspection); and tree fall across the fence line.

Sheep fencing requires closer wire spacing than cattle fencing to prevent lambs and small sheep from pushing through. Standard ringlock mesh with a 150mm bottom wire spacing is appropriate. Sheep respond well to electric fencing once trained, and a three-wire electric system (300, 600, and 900mm heights) is reliable for trained sheep. The primary failure mode is the bottom wire — sheep test the ground clearance under any fence and will duck under a wire at 200mm or more above the ground. Clip or tie the bottom wire of mesh fences to pegs or staples at the base to prevent lifting.

Goat fencing is the most demanding of any common Australian livestock species for the reasons detailed in the goat housing and management guide — they jump, they climb, they test every weakness, and once they discover a weakness they return to it reliably. The minimum for goat-proof permanent fencing is 1.05 to 1.2 metre high ringlock or goat-specific mesh, with no gaps at the base (goats will squeeze under a lifted bottom wire with remarkable ease), and no horizontal rails that could serve as a climbing ramp. Electric fencing for goats requires a four to five wire system with the bottom wire at 150mm and adequate voltage (minimum 4,000 to 5,000 volts on the fence under load). Once trained, goats respect electric fencing reliably — the initial training event is what they remember and act on for years.

Horses require high, visible fencing — horses run at fences rather than test them, and a wire fence that is not clearly visible can result in a horse running into it at speed with severe injury consequences. Post and rail fencing is the traditional and safest option for horse paddocks, though its cost per metre is substantial. V-mesh (no-climb) horse mesh is a widely used and safer alternative to standard cattle ringlock for horses. Avoid barbed wire entirely for horse paddocks — lacerations from barbed wire are a major source of veterinary emergency on Australian horse properties. Highly visible electric tape (polytape rather than polywire) works for internal subdivision of horse areas, as horses respect it readily once trained and can see it clearly at distance.