Sample preparation of Medicago sativa L. hay for chemical analysis

The objective of this study was to quantify the effect of the grinding procedure on the moisture and crude protein concentration of a ground Medicago sativa L. hay sample for quality grading. An additional aim was to investigate the accuracy of electronic moisture testers (EMT). Variance of analyses revealed significant differences in moisture concentration between ground (CV = 16.1%) and unground (CV = 27.4%) samples ranging from 14.7 up to 41.1% of the unground sample. The grinding process had a non-significant influence on the CP concentration of the final grounded product. EMT failed to accurately predict moisture concentration around the moisture area of critical concern (16% and higher) where heat and/or mould damage are likely to occur. It was concluded that analytical moisture standards for Medicago sativa L. hay should be based on the original moisture concentration of samples in the unground state to be relevant for quality grading.