Farm roadways are a vital piece of infrastructure on any farm and the Teagasc Dairy Infrastructure Handbook which was launched at the Moorepark open day last year outlines what to consider when designing a roadway and the associated costs involved.

The cow flow on your farm should be carefully examined to identify where there are any bottlenecks on roadways. Is this due to a poor surface, tight right-angled turns or roadways that are too narrow? Any turns on the roadways should be sweeping bends and not 90-degree angle turns as they will only form a bottleneck that will cause bunching of cows.

Benefits

There is a large variation in the quality of farm roadways present on Irish farms, with major upgrades needed in many cases. A good roadway can have many benefits ranging from a greatly improved cow flow to a reduction in lameness. When it comes to lameness, the surface of the roadway needs to be smooth, fine and strong enough to support animals but with a little give in it also in order to reduce lameness issues.

Farm roadways also allow for much more efficient grazing, especially in the shoulders of the year when ground conditions may be more difficult. A roadway was recently installed on the Teagasc Curtins research farm located in Fermoy, Co Cork. Along with the main roadway, another spur road off one of the main tracks was also installed to allow for paddocks to be split which has allowed for more efficient grazing.

Even though the farm was visited on a very wet day there was no damage done to the roadways by cows and there was very little, if any, water sitting on the roadway. All signs of a good design. Getting water off roadways as quickly as possible will help to reduce the amount of potholes that will develop over time.

Another good feature of this roadway is that there are cows’ tracks running right across the surface of the road, showing that the entire surface is suitable. Often where roadways are in poor condition all cows will try and stick to the one track which will greatly reduce cow flow.

As seen on Curtins Farm, space between every post can act as a gateway into a paddock. This can help reduce damage and wear and tear to the roadway at any one certain point with both tractor and cow traffic spread out between multiple access points.

The main roadway through the farm is approximately 4.3m wide. The height of the roadway has to be balanced between being high enough to ensure water can run off the road and not being too high as to lead to difficulties when entering or exiting the field with machinery.

A geotextile membrane between the stone and the soil underneath is another option for a farm roadway. This can help prevent soil becoming mixed with the stone and is strongly recommended where soils are heavy or there is wet land. It is also recommended for roadways that will be used for heavy machinery as it also provides physical support by keeping the material dry.

The foundation layer should be 200-300mm deep and made with 75-100mm down material.

The foundation layer should be 200-300mm deep and made with 75-100mm down material.

Construction

When constructing a farm roadway, you want the surface of the roadway to be above field level and this must be taken into account when removing a thin layer of topsoil for the roadway. Removing too much soil will result in the need for excessive levels of fill to rise up the surface of the road again.

Teagasc recommends that this foundation layer should be 200-300mm deep. The foundation layer should also be sloped to allow for water to run off the road with the top layer spread evenly over this.

Generally 75-100mm down material is used which is a graded mixture of different sized stones from 70-100mm down to dust. Crushed rubble is also an option which may be available on the farm from recent construction work, for example. This can greatly reduce the cost of the roadway.

This layer should be compacted with a vibrating roller before the surface layer is spread. This compaction also helps to prevent loose stones from mixing with the surface layer which can become an issue as the road wears over time.

The top layer of the road should consist of fine material and be between 50mm to 75mm deep.

The top layer of the road should consist of fine material with no large stones present. It should be between 50 to 75mm deep and again it needs to be spread evenly and well compacted.

The road should be sloped to one, or both sides to allow for water to run off as quickly as possible. You want water to move off to the side and not run down along the road as any steep slope on the road will leave the fine material at a bigger risk of being washed off.

A slope of 1:20 is recommended for a one-sided slope and 1:15 for a two-sided slope, in this example the road is sloped to both sides. The fencing along the side of the roadway should be 0.5m back from the edge of the roadway to allow cows to utilise the full width of the road without walking on the grass verge.

Walking on the grass verge can lead to banks forming which can keep water on the roadways.

When it comes to the actual width of the roadway, Teagasc recommends that typical widths of 3.7m to 5m are required for herds up to 150 cows and 0.5m wider for every 100 cows extra. With dairy farms experiencing rapid expansion over the past number of years it may be worth looking at the width of your roadways and if they are still up to scratch.

A new spur roadway has also recently been construicted to provide better grazing access to paddocks.

A new spur roadway has also recently been construicted to provide better grazing access to paddocks.

Costs

It is worth doing the sums before you break ground for a new farm roadway as they can be a significant investment with approximate costs of €18 to €30/m. This could see the cost of a 500m section of roadway vary from €9,000 to €15,000, which represents a significant variation. The top layer of the roadway is expensive material but it is vital to good cow flow and to reduce lameness.

The price of the road-making material including both crushed stone and dust for the surface is typically €7-10 per tonne not including VAT which is at 23%. It is important to note that the VAT cannot be claimed back for repairing roadways but it can be claimed back for new roadways. One 25t load of the larger material for a foundation layer on a roadway that is 4.3m wide will cover between 9-10m. A 25 tonne load of finer material that is 63mm deep will cover approximately 45m.