Post-sampling procedure affects the measured nutritive value of perennial ryegrass (Lolium perenne)

Abstract

<jats:p>Abstract Estimates of pasture nutritive value are affected by how samples are stored and dried before laboratory analyses. To determine which post-sampling procedures best preserved nutritive value, a range of procedures were compared for one diploid and one tetraploid perennial ryegrass cultivar in June 2016 and April 2017. Treatments included different combinations of transportation from the field to the laboratory either in liquid nitrogen or in a chilly-bin with ice-packs, storage at room temperature (19°C), a chiller (3°C), standard freezer (-18°C) or a -80°C freezer, and drying either in a freeze-drier or an oven at 65°C for 48 hours. Samples were sent to a commercial laboratory for near-infrared reflectance spectroscopy analysis. Values were higher for one or more of metabolisable energy, soluble sugars, non-structural carbohydrate, and organic matter digestibility, and lower for neutral detergent fibre and ash, when comparing transportation in liquid nitrogen with a chilly-bin, freezer storage (-80°C and standard freezer) with chiller and room temperature storage, and freeze-drying with ovendrying (P</jats:p>

Metabolisable energy concentration in perennial ryegrass pastures: multi-site analysis of effects of cultivar, nitrogen fertiliser and white clover content

“…The different sample drying methods used may have influenced the estimates of ME. In a recent study, freeze-drying compared with oven-drying resulted in a small (3%, or 0.35 MJ ME/kg DM), but significant (P<0.01) increase in ME (Dale et al 2017).…”