FREEZING AND THAWING DO NOT ALTER PARTICLE DISTRIBUTION IN TOTAL MIXED RATION (TMR) EVALUATED WITH THE PENN STATE SEPARATOR
DOI:
https://doi.org/10.56238/revgeov17n4-142Keywords:
Coefficient of Variation, Diet Freezing, Precision Nutrition, Physical VariabilityAbstract
The objective of this study was to evaluate whether freezing and thawing total mixed ration (TMR) samples alter particle size distribution and compromise the assessment of diet homogeneity using the Penn State Particle Separator. A total of 144 TMR samples offered to lactating cows were collected and sieved immediately after sampling (fresh) or after freezing for 72 hours (−25 to −18 °C) and thawing for 12 hours. The proportions of particles retained on the 19-mm and 8-mm sieves and in the bottom pan, as well as the coefficients of variation (CV), were compared using paired t-tests (p < 0.05). The results showed no significant differences (p > 0.05) between treatments, with variations lower than 1 percentage point in the analyzed fractions. Freezing also did not affect SD and CV values, indicating maintenance of the physical uniformity of the diet. The high CV observed on the 8-mm sieve reflects failures in the mixing process, not attributable to freezing. The freezing TMR samples for up to three days, followed by controlled thawing, does not alter the particle size distribution of the diet and is a safe and applicable method for routine evaluations of diet homogeneity in dairy systems.
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