| Buildings
Improve animal health through improved building environment
Ventilation guide outlines best practices to improve animal health and increase profits.
M aximising livestock performance is dependent on the synergistic relationship between animal welfare and animal health,” explains agricultural specialist Stuart Daniell for fibre cement manufacturer Marley Eternit.“ Ventilation plays a huge role in making sure these components work together.”
To give beef, dairy, pig and youngstock producers the knowledge resource to provide optimum housing conditions for livestock buildings, Marley Eternit developed the“ Livestock building design and material guide for natural ventilation.”
Below, Stuart outlines a few best practices from the ventilation guide Stack effect“ For natural ventilation to occur, buildings must be designed for the stack effect to proficiently manage the air inlet and air outlet cycle,” says Stuart. How the stack effect works
Air inlets draw in cool air which exits the building through air outlets as it begins to warm. If designed properly, this cycle keeps the internal building environment dry and fresh without becoming draughty. How to get air outlet
There is no‘ one-size-fits-all’ standard for air outlets, which can be obtained in multiple products and designs. Installing ridge sections is a good way to prevent rain ingress while enhancing the draw of air through the top of the building, explains Stuart. Unprotected open ridge section:
Unprotected open ridge sections deflect rain as air moves up the slope of the roof. This negative pressure also enhances the draw of air through the open vent.
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Protected open ridge section:
“ A protected open ridge has a covering to prevent rain ingress and can be built with a traditional fibre cement soffit strip or polycarbonate soffit strip,” explains Stuart.“ Polycarbonate soffit strips allow more natural light into the building while avoiding hot spots caused by low level glass reinforced plastic.” Breathing and spaced roofs:
“ Air outlet can also be achieved by installing semi-compressed fibre cement profiled sheets as breathing or spaced roofs,” says Stuart. When being used with the addition of open ridge sections, breathing roofs are a good solution for increasing air outlet capacity in buildings with high stocking rates. Spaced roofs also aid in air outlet while increasing natural light but make buildings unsuitable for anything other than housing adult cattle.
Air outlet calculations and in-depth information about different air outlet options can be found on page six of the guide. How to get air inlet
Managing airspeed is essential to maintain adequate air inlet without making livestock uncomfortable. While configuring air inlet for adult cattle can roughly be achieved with two evenly split sidewalls that are four times the size of the outlet area, greater consideration for airspeed is needed for youngstock and pigs.“ One of the biggest mistakes livestock producers can make when trying to prevent air draughts is to completely seal off a wall. This will put an end to the stack effect cycle and create a stale, stagnant environment,” explains Stuart.
Find air inlet calculations and airspeed considerations on page seven of the guide. Roofing materials
“ Roofing materials are going to have a
significant impact on the long-term profitability and efficiency of a farm, so it is important to choose materials that have a positive impact on the entire production picture for decades to come,” explains Stuart.“ Properties like humidity levels, sound reverberation, light control and temperature stability are key things to focus on.” Metal sheeting:
While metal sheeting may seem like the cheapest option up front, it can be very costly over time due to a short-lived life expectancy of 10 to 25 years in the damp UK climate.
“ Metal sheeting also has high thermal conductivity that can cause rapid temperature swings, and its inability to absorb moisture can also result in elevated humidity levels,” says Stuart.“ This creates conditions that can compromise animal health.” Fibre cement profiled sheeting:
While being rot, rust and corrosion resistant, semi-compressed fibre cement has a life expectancy of at least 50 years. It is also capable of absorbing up to 25 percent of its own weight in moisture, greatly reducing humidity levels in buildings.
“ The low thermal conductivity properties of semi-compressed fibre cement help create a mild internal building environment year-round. It also absorbs sound, reducing rain reverberation,” says Stuart.“ All of these properties lead to happy, healthy and more productive animals.”
To download the“ Livestock building design and material guide for natural ventilation” e- book or to request a free hard copy, go to www. marleyeternit. co. uk / ventilation-guide
August 2018 | Farming Monthly | 35