THE AGREEMENT AND REPEATABILITY OF ATLAS AND STAPLEBREAKER FOR ESTIMATING THE STAPLE STRENGTH OF MIDSIDE WOOL SAMPLES TAKEN FROM MERINO SHEEP

Atlas and Staplebreaker are two machines that may be used to estimate the staple strength of wool. This study provides an assessment of the agreement between Atlas and Staplebreaker for measurements of staple s trength of mid-side samples of Merino wool and an estimate of the repe atability of the two methods. Mid-side samples were taken from 71 Meri no ewes in full wool. From each sample, 10 staples were removed for te sting using the Staplebreaker and 10 staples were removed for testing using the Atlas machine. The remainder of the sample was used to estim ate yield and vegetable matter. Staplebreaker and Atlas were used acco rding to normal commercial operating instructions. There was good agre ement between Atlas and Staplebreaker estimates of staple strength. At all staple strengths, there was very little bias in Staplebreaker est imates (0.096 N/ktex) when compared to Atlas measurements. Ninety five percent of the measurements were expected to be within 7 N/ktex of ea ch other. The estimated repeatability of the Atlas was 4.13 N/ktex and the estimated repeatability of the Staplebreaker was 3.79 N/ktex.