Artificial bedding surfaces

Cows housed on hard surfaces, such as concrete, solid or slatted floors, and river stones, experience increased lameness, stiffness, and agitated behaviour. They can have reduced dry matter intakes, and lower body condition scores. To create a comfortable lying surface, additional bedding material must be added to these hard floors.

Common artificial surfaces include rubber mats, recycled materials, sawdust, straw, and wood chips. These materials provide a soft, compressible surface that is more comfortable for cows to lie on compared to hard surfaces like concrete.

Assessing artificial surfaces

Artificial surfaces such as rubber matting are widely used in cubicle housing designs, on concrete yards and feed pads to improve cow comfort. Rubber overlays can be used to improve comfort for standing and lying cows. However, it is important to think about how you will maintain the rubber, as it can become slippery when wet and unhygienic as it deteriorates. Not all rubber will increase cow comfort, so select wisely.

Comfort: The combination of the top surface and sub-base should provide sufficient compressibility to enable natural resting behaviour, reduce fatigue when standing, and cause minimal abrasions.

Traction: The surface must offer sufficient slip resistance to support normal movements and behaviours, including walking, transitioning between standing and lying, grooming, and social interaction, with minimal slipping.

Durability: Surfaces should withstand animal and vehicle loads, maintaining their integrity over their life cycle with practical maintenance and replacement intervals.

Cleanability: Cleaning should be practical and low labour, such as through flood washing or scraping, to maintain hygiene and animal cleanliness. It is also important to prevent the pooling of liquid on surfaces, as standing water can create hygiene issues and increase the risk of hoof health problems.

Sustainability: Preference should be given to materials with a low environmental impact, e.g. renewable, waste, or low-impact components, and have an acceptable disposal plan at the end of their life cycle.

Economics: The life cycle cost must be affordable, with designs typically supporting more than one purpose to add value.

International organisations provide suppliers with practice-oriented independent laboratory testing of materials according to DIN Standard 3763, including animal flooring surfaces. Tests can include compressibility (deformability and elasticity), abrasion resistance, slip resistance, and chemical resistance and can provide a materials comparison.

Field testing of surfaces

Understanding the performance of artificial surfaces in off-paddock facilities can be challenging due to subjective assessments. To address this, DairyNZ completed objective field-testing to evaluate the performance of various loafing surfaces and sub-base combinations under typical farming conditions. Comfort levels were correlated with cow lying duration and bouts.

Average daily cow lying times for tested surfaces:

• Post peelings (woodchip): 11.5 hours per day.
• Shredded rubber playground surface (50mm) with geotextile overlay (6 mm )NUMAT: 11 hours per day.
• Rubber and plastic chip sports turf underlay (25 mm) with geotextile overlay (6 mm) Tiger Turf: 10.5 hours per day.
• Interlocking rubber matting (25 mm × 1 m²) NUMAT: 8 hours per day.

The comfort (compressibility) performance of rubber matting is influenced by material density, thickness, and the structured pattern under the mat, which allows deformation rather than just compression. The surface pattern and compressibility also affect slip resistance; a higher profile surface pattern provides more grip but may be uncomfortable for cows and cause abrasions.

To measure the 'comfort' of loafing surface materials, a 2.25 kg Clegg hammer, an accelerometer-based device used internationally for sports fields, was used. The results, shown as Gmax values, quantify the hardness of a surface, with higher Gmax values indicating firmer surfaces and shorter lying times. The Turf Clegg hammer results demonstrated a clear range, least firm - post peelings, firmest - rubber matting.