Refurbishing dairy buildings
At the end of a difficult winter many dairy farmers’ thoughts will turn to how they can refurbish or improve farm buildings whilst the cows are out this summer. Here we offer some top tips to consider…
Refurbishing an existing building provides a great opportunity to improve the environment for the cows whilst also extending the useful life of the building. Yet there are a number of factors to consider before embarking on a major refurbishment.
An opportunity to upgrade
Perhaps your buildings have suffered some storm damage over the winter? Maybe roof sheets or cladding have become loose or damaged? Or perhaps some of the materials in the building are simply worn out and in need of replacement. Perhaps you are looking to repair or replace internal fittings such as water troughs, gates, feed barriers or cubicles. Before rushing in and replacing on a like for like basis, consider whether you can improve the environment within the building. Is ventilation as good as it could be (see below) and does the building provide the right layout and space for the animals within it? Are there sufficient water troughs and enough feed space? Consider getting advice from a husbandry expert or your veterinary surgeon to establish the best layout and specification for your requirements.
Repairing the roof
Metal roof sheets eventually rust out and fibre cement can become brittle as it ages and more prone to damage if disturbed. Often it is the fixings that deteriorate before the sheets themselves, whilst roof lights can become discoloured and ineffective. If you are replacing the roof as a result of damage or wear, consider your options and think about whole life cost rather than simply going for the cheapest option at the outset. Fibre cement profiled roof sheets have a design life of in excess of 50 years compared to 10-30 for coated-metal sheets, and don’t rust or rot. They are also resistant to chemical attack from slurries and effluent. Perhaps more importantly, however, they create a better environment for livestock. The vapour permeable nature of fibre cement profiled roofing means it absorbs moisture and minimises condensation dripping from the roof and on to livestock or bedding underneath. Compared to metal, fibre cement roofing is also more thermally stable, reducing heat build up in the summer and cold in winter. It also deadens sound - avoiding drumming from rain that can upset livestock.
One thing to be aware of, however, is that the fixing requirements of fibre cement roofing are different from those of metal sheets, so, unless you are swapping like for like, make sure you check with the manufacturer to avoid problems later on.
Good ventilation is critical to the health and welfare of the herd; yet older buildings often fall short of recommended best practice. This is not a situation where one size fits all, as ventilation requirements depend on the number and size of stock, the dimensions of the building, the roof pitch and the prevailing weather conditions. The ventilation requirements should ideally be designed to suit the stock levels within the particular building.
The general principle, however, is that heat rising from the cattle will drive stale air out of the highest point of the building, to be replaced with fresh air coming in from the sides of the shed. Yet if the ridge doesn’t allow sufficient airflow the warm air can’t escape and will increase humidity in the shed. Ideally the ridge should be left open, or a protected open ridge should be fitted. The upstand flashings of the open protected ridge and open unprotected ridge are particularly efficient at removing stale air from within the building. Air passing over the roof is diverted upwards by the upstand flashing, creating a venturi effect to draw the air out of the building. Cranked ridges are still routinely used but don’t normally provide sufficient area for adequate ventilation and are not generally recommended for this type of application. Spaced roof sheets can be effective and sheets should be placed 15-25mm apart to provide sufficient airflow without snow bridging or rain ingress.
But even if the ridge provides sufficient ventilation, if the sides of the building don’t allow fresh air in, then air movement will be compromised. DairyCo recommend that the inlet area should be at least twice the outlet area, and ideally four times, and should be located at the sides of the building for optimal air flow, but above the level of the stock to minimise cold draughts. Spaced boarding or windbreak materials offer a cost effective solution.
There have been a number of studies that demonstrate that improving light levels in buildings can increase milk output as well as making the environment more pleasant to work in.
Ideally you should aim for 200 lux at cow level for 16 hours a day, with 8 hours of darkness. Old and discoloured roof sheets can seriously compromise light levels and replacing with new roof lights can make a massive difference to the shed. Aim for between 10 and 15% of the roof area as roof lights, with more on a north-facing slope than on a south facing side to prevent excessive solar gain during the warmer months.
Internal fittings and fixtures
The summer provides a good opportunity to review existing fittings and fixtures and identify any problems. Are there sharp edges that could injure livestock? Is concrete in good condition and does it provide sufficient grip? Concrete grooving or the use of rubber matting can have a big impact on cow comfort, locomotion and, ultimately, can lead to reduced lameness levels.
Are water troughs in good condition and are there sufficient troughs for the number of stock? DairyCo recommend 10cm of trough space per cow and that trough edges are 850mm from the ground. Think about placement of troughs in the building to ensure adequate access.
And, if you are considering replacing cubicle divisions or changing the dimensions of your cubicles then consult your vet or adviser to make sure that you select the best approach for your own herd.
Health & Safety
Health and safety considerations are critical if you are planning any kind of work at height or work to the roof area of a building. Stripping off old roof sheets requires great care as metal sheets can be badly corroded and old fibre cement sheets can become extremely brittle. HSE provide various leaflets on safe working practices on roofs, including work on fragile roofs.
If the sheets are old they may well contain asbestos and will require removal by trained and competent personnel, and disposal at a licensed asbestos waste tip. Again, HSE provide guides on the removal of asbestos cement sheets and your local authority will advise on the disposal of the asbestos waste.
And remember, even if the work is being carried out by contractors then you share some of the health and safety responsibility as building owner, so make sure that work is being undertaken in a safe way.
If you are looking for more information then there are a number of useful resources available. DairyCo publish a free best practice guide to dairy housing (www.dairyco.org.uk) and the Rural and Industrial Design and Building Association (www.ridba.org.uk) publish a farm buildings handbook that contains a great deal of useful information. The Health and Safety Executive (www.hse.gov.uk) provides various leaflets and brochures regarding working on roofs and working with asbestos.