Effects of Temperature and Duration of Sample Storage Before Oven-Drying on Forage Fiber Analyses

Abstract

In a 4 × 5 × 5 factorial experiment, replicate samples of fresh alfalfa, alfalfa silage, fresh corn forage, and corn silage were sealed in plastic bags and assigned randomly to storage treatment combinations of −20, 5, 10, 21, or 38°C for periods of 0, 24, 48, 96, or 192 h. Following storage, samples were ovendried, ground, and analyzed for NDF, ADF, and lignin. Forage and time effects and forage by time interactions were significant for most parameters measured. In general, corn was affected more by storage temperature and time than alfalfa, and fresh forages were less stable than ensiled forages. Storage time had a significant effect on most parameters across temperatures for fresh corn forage. When affected, fiber components and ash generally increased during sample storage. Increased fiber component concentrations were apparently due to both respiration and fiber component deposition. Fiber components increased at some temperatures more than others. Significant changes in fiber content may occur between sample collection and drying, which appears to be especially important for fresh chopped forages. Fresh forage samples should be dried immediately, or ensiled forage should be sampled rather than fresh to minimize storage effects.