IMPACT TESTING TO ASSESS THE SOFTNESS OF FREESTALL RESTING SURFACES

Sand is a common bedding material used as a resting surface for dairy freestalls because it does not support bacterial growth, and it provides a high degree of comfort to cows. Existing techniques of assessing the comfort of freestall resting surface materials in the field are subjective, so the objective of this study was to evaluate the use of a Clegg Impact Tester as a method to assess the comfort of sand and various other freestall resting surface materials. The Clegg tester was developed to characterize the stiffness of soils and soil-like materials. The Clegg tester displays a Clegg Impact Value (CIV) based on peak deceleration of the hammer's impact with a surface from a height of 30 cm, which can be related to the design elastic modulus of a given material. A Clegg Impact Soil Tester with a 1-kg hammer was used in this study. Values were recorded for a rubber mat, a soft foam mat, a hard foam mat, and a waterbed and then were compared with values from sand with varying moisture content. The softest resting surface material was the soft foam (1.07 CIV/L) followed by dry sand (moisture content <0.75%) (1.57 CIV/L). The hardest material was the rubber mat (64.23 CIV/L). The softness of the waterbeds varied with the change in water pressure and volume in both the small and large chambers of the waterbeds.