A21 Livestock housing floor design to reduce nitrogen emissions
Last Update:
| Measure | Sector | Net Effect | Impact | Reliability | Tech. rqmt. | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| NH3 | N2O | NOx | Nr to water | N2 | ||||||
A21 Livestock housing floor design to reduce nitrogen emissions  | Sector Livestock farming | Net Effect 1 | NH3 1 | N2O  | NO2 | Nr to water | N2 | Reliability Robust | Tech. rqmts. Medium |
Overview
Ammonia is generated through the breakdown of excreted urea in both the urine and faeces of animals. This process leads to the formation of ammonium ions in the liquid layer, such as slurry or urine pool, which can be subsequently lost to the atmosphere at the air-liquid layer boundary during the volatilisation phase. This can be a significant concern in livestock housing, especially when poor ventilation conditions permit the accumulation of higher concentrations of ammonia. Elevated ammonia levels can potentially have adverse effects on the health of both animals and workers in the facility.
The flooring in animal housing can play a vital role in this process by promoting effective drainage and preventing the accumulation of urine on the surface. By reducing the exposed surface area of slurries in contact with the air, flooring design can contribute to minimising ammonia emissions (Swierstra et al., 2001; Bittman et al., 2014). This aspect is particularly critical in enclosed animal housing facilities, where ammonia buildup can be more pronounced.
Various flooring designs are available for all types of livestock and animal housing facilities, including cattle, poultry, swine, dairy, multi-species, and animal research facilities. Common options include:
Grooved Flooring: With small channels or grooves, this design improves drainage and decreases the surface area exposed to waste and air, reducing ammonia volatilisation (Figure 1).
Slatted Flooring: Featuring solid sections alternated with open slots, slatted flooring facilitates waste drainage and helps reduce ammonia formation (Figure 2).
Perforated Flooring: Similar to slatted flooring, perforated flooring incorporates small holes or perforations to optimise waste removal and minimise ammonia emissions.
Composite Flooring: Combining solid surfaces with grooved or slatted sections, composite flooring offers a balance between comfort and effective waste management.
Flooring design, along with regular cleaning, removal, and appropriate storage of animal manures, is a reliable and effective measure for reducing ammonia emissions from animal slurries. Technological requirements for implementing these flooring systems are considered to be basic to intermediate, depending on the chosen flooring type. By integrating smart flooring designs and management practices, livestock farmers can significantly improve ammonia control and create a healthier environment for both animals and workers.
Figure 1. Showing a “grooved floor” system, which is appropriate for dairy and beef cattle housing and can help to reduce the surface area of wastes. Image source: pixabay.com
Measure Efficiency
In a study conducted by Pereira et al., (2011), scale models were constructed to replicate two types of flooring observed in dairy cattle housing: a level solid floor without urine drainage and a slatted concrete floor. To simulate real-life conditions, a mixture of urine and faeces was applied to each floor-type model. Both models were subjected to a constant airflow rate (12.5 exchanges per hour), and gaseous emissions were measured over 72 hours. The results of the study showed that cumulative ammonia emissions accounted for 27-66% of the total nitrogen applied and were higher from the solid floor compared to the slatted floor, with a difference of 36%. On the other hand, cumulative nitrous oxide emissions were relatively low, accounting for less than 0.1% of the total nitrogen applied.
In summary, the study demonstrated that the slatted concrete floor exhibited lower emissions of ammonia and carbon dioxide compared to the level solid floor without urine drainage. While nitrogen dioxide and methane emissions were relatively low for both flooring types, they did not differ significantly between the treatments.
Bittman et al., (2014) reported that a grooved floor system in cattle housing, employing “toothed” scrapers running over a grooved floor, can reduce ammonia emissions by 25% to 46%, relative to a slotted floor (i.e. wastes collect in slots and are not free to drain).
How to implement
Implementing better flooring design in animal housing involves careful planning, consideration of animal welfare, waste management, and environmental factors. Here are steps to help achieve a more effective flooring design:
- Assess Animal Needs: Understand the specific needs and behaviours of the animals being housed. Different species and age groups have different requirements for comfort, traction, and waste management. All surfaces on which animals walk should be easily cleaned and provide adequate traction to prevent slipping and falling. The provision of slip-resistant flooring in collecting yards and parlours will also be beneficial.
- Research Flooring Options: Investigate various flooring materials and designs available on the market. Consider factors like durability, ease of cleaning, waste removal, and slip resistance.
- Choose Suitable Materials: Select flooring materials that promote animal comfort and are easy to maintain. For example, rubberized flooring can provide better cushioning for hooves or paws, while concrete or slatted flooring can aid in waste removal. The floor should provide sufficient slip resistance when covered in slurry, at all times of the year.
- Plan for Proper Drainage: Ensure that the flooring design promotes efficient drainage of urine and waste. Properly sloped and graded flooring helps prevent the pooling of liquids, reducing ammonia formation. Floors must be properly drained and treated in such a way to prevent slipping with a gentle gradient to provide good footing. The slope of the floor should not be more than between 1.5-3%.
- Integrate Ventilation: Combine smart flooring with effective ventilation systems to disperse ammonia and improve air quality. Proper airflow prevents the buildup of harmful gases and promotes a healthier environment.
- Consider Waste Management: Incorporate waste management systems, such as automated scrapers or flushing mechanisms, to keep the flooring clean and reduce ammonia emissions. It is important to ensure wastes do not collect within the grooves of such flooring systems. Waste can be cleaned from a grooved flooring system using a handheld tool. Automatic scrapers can also be installed. These scrapers run frequently to remove waste material from the passages within the building. The scrapers either deposit the slurry outside the building on a hard standing for collection by a tractor scraper or scrape directly into a slurry lagoon or slurry channel.
- Regular Maintenance: Establish a regular maintenance routine to keep the flooring in optimal condition. Regular cleaning, repair, and replacement, when necessary, will extend the life of the flooring and ensure its effectiveness.
- Monitor and Adapt: Continuously monitor the performance of the flooring design and be open to making adjustments based on animal behaviour, health indicators, and facility requirements.
- Educate Staff: Ensure that staff members are trained in the proper care and maintenance of the flooring and understand its importance in promoting animal welfare and reducing environmental impact.
By following these steps and customising the flooring design to suit the specific animal housing needs, the operation can implement a better flooring system that enhances animal well-being, optimises waste management, and minimises ammonia emissions, contributing to a healthier and more sustainable environment for both the animals and the caretakers.
Figure 2: Showing concrete slatted flooring appropriate for use for housing pigs or sheep (Image source: https://www.spanwright.co.uk/product/pig-slats/.).
Benefits
It's important to note that each flooring type has specific considerations and maintenance requirements. For instance, slatted flooring may need more regular cleaning, while grooved flooring should be designed to avoid discomfort for the animals. Considering factors such as animal size, behaviour, and overall management goals will aid in selecting the most suitable flooring system to optimise animal welfare and productivity while minimising ammonia emissions and environmental impact.
Costs
Captial Costs
The capital costs of flooring systems in livestock housing can vary depending on various factors, including the type of flooring, the size of the facility, the quality of materials used, and the specific requirements of the livestock. A general overview of the capital costs associated with slatted flooring, grooved flooring, and composite flooring:
Operational Costs
Risks
While slatted flooring, grooved flooring, composite flooring, and perforated flooring offer various benefits in livestock housing, they also come with certain risks and considerations. It's essential to be aware of these potential drawbacks to make informed decisions about which flooring type is best suited for the specific livestock facility. Here are some risks associated with each flooring type:
It's essential to work closely with flooring experts, animal behaviourists, and veterinarians when selecting and designing flooring systems for a livestock facility. Each flooring type has specific requirements for proper installation, maintenance, and waste management. Regular monitoring and timely adjustments can help mitigate some of the risks associated with these flooring types.
Ultimately, the goal is to choose a flooring system that optimises animal welfare, waste management, and ammonia reduction while addressing potential risks and challenges specific to the livestock housing facility.
References
Bittman, S., M. Dedina, C.M. Howard, O. Oenema, and M.A. Sutton, editors. 2014. Options for Ammonia Mitigation: Guidance from the UNECE Task Force on Reactive Nitrogen. Centre for Ecology and Hydrology, Edinburgh, UK.
Pereira, J., D. Fangueiro, T.H. Misselbrook, D.R. Chadwick, J. Coutinho, et al. 2011. Ammonia and greenhouse gas emissions from slatted and solid floors in dairy cattle houses: A scale model study. Biosyst. Eng. 109(2): 148–157. doi: 10.1016/j.biosystemseng.2011.02.011.
Swierstra, D., C.R. Braam, and M.C. Smits. 2001. Grooved Floor System for Cattle Housing: Ammonia Emission Reduction and Good Slip Resistance. Appl. Eng. Agric. 17(1): 85–90. doi: 10.13031/2013.1929.
Authors
Will Brownlie
UK Centre for Ecology and Hydrology, Scotland