Precision in the measurement of dairy feed fractions based on particle size.

<p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">The aim of this research note is to evaluate the variability of the physical measurements obtained by a separator of feeds<span style="font: 12.0px Helvetica;">&nbsp;</span></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">for dairy cows based on particle size. Fresh samples of total mixed ration (TMR) and corn silage were collected from four<span style="font: 12.0px Helvetica;">&nbsp;</span></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">dairy units and were immediately fractionated using a particle separator (NASCO&reg;, Pennsylvania State University) com-<span style="font: 12.0px Helvetica;">&nbsp;</span></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">posed of two sieves (diameters of 19 and 8 mm) and a collector on the bottom. Repeatability expressed as standard devi-<span style="font: 12.0px Helvetica;">&nbsp;</span></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">ation was similar between fractions (>19, 8-19 and <8 mm fractions: +1.9, +1.4 and +2.2% for TMR samples; +2.0,<span style="font: 12.0px Helvetica;">&nbsp;</span></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">+1.7 and +1.5% for corn silages), but when expressed as coefficient of variation there were, for both samples, large dif-<span style="font: 12.0px Helvetica;">&nbsp;</span></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">ferences between the values for fraction exceeding 19 mm (44.7 and 35.1 %, respectively for TMR and corn silages) and<span style="font: 12.0px Helvetica;">&nbsp;</span></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">the middle (3.9 and 2.5 %, respectively for TMR and corn silages) and bottom fractions (3.7 and 5.6 %, respectively for<span style="font: 12.0px Helvetica;">&nbsp;</span></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">TMR and corn silages). The between operator reproducibility was very close to repeatability and this indicates that the<span style="font: 12.0px Helvetica;">&nbsp;</span></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">operator&rsquo;s contribution to the overall variability is marginal in comparison with residual variability. In conclusion, differ-<span style="font: 12.0px Helvetica;">&nbsp;</span></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">ent operators properly trained in the use of the NASCO&reg; separator can produce satisfactory repeatable and reproducible<span style="font: 12.0px Helvetica;">&nbsp;</span></p> <p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 8.0px Verdana;">values for the middle and the bottom fractions.<span style="font: 12.0px Helvetica;">&nbsp;</span></p><div><span style="font-family: Helvetica, Arial, Helvetica, sans-serif; font-size: small;"><span style="font-size: 12px;"><br /></span></span></div>

Abstract licence: CC BY-NC

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