## 3 Results  
The means, standard deviation, and minimum and maximum values for PCDMD and chemical composition determinations obtained in 1987 for the 18 maize samples used in this experiment are given in Table 1. The coefficient of variation between the samples ranged from 5.25 for PCDMD to 49.5 for starch. There were no differences between the storage methods (frozen vs. barn temperature over 29 years) for ash, CP, NDF, ADF, ADL, starch, and PCDMD. The TSC content was lower for the samples stored at barn temperature for 29 years (\(p<0.001\)) (81 g/kg DM) than for the samples stored frozen for 29 years (93 g/kg DM). The ash content was significantly different between the samples analyzed in 1987 and 2016 (55 vs. 56.5 g/kg DM respectively; \(p<0.01\)), but no difference was obtained between the storage methods (56 vs. 57 g/kg DM for samples stored at barn temperature or frozen, respectively; \(p>0.05\)). The TSC significantly differed (113 vs. 87 g/kg DM) between 1987 and 2016 (\(p<0.001\)). The TSC stored at barn temperature decreased by 28% in relation to the TSC content obtained in 1987 just after harvesting the samples, whereas the TSC of the samples stored frozen for 29 years decreased by only 18% in relation to the original value measured in 1987. The starch content (\(p>0.05\)) did not vary over time in storage nor between frozen vs. barn-temperature samples (Table 2). The averaged second-derivative NIR spectrum for frozen and barn-stored whole-maize forage samples is presented in Figure 1a. Whole-maize forage samples presented bands with peaks at 660, 728, 750, 1420, 1920, 2022, 2248, 2314, and 2412 nm. The different spectra between the second-derivative NIR spectra for the frozen and barn-stored samples is presented in Figure 1b. The average spectra for both storage methods showed substantial differences at 660, 698, 728, 1420, 1920, and 2066 nm. \begin{table}
\begin{tabular}{c c c c c c} \hline  & **Mean** & **SD 2** & **Min 3** & **Max 4** & **CV 5** \\ \hline Ash (g/kg DM 1) & 55 & 6.5 & 45 & 67 & 11.8 \\ CP (g/kg DM) & 84 & 8.2 & 69 & 99 & 9.8 \\ NDF (g/kg DM) & 488 & 39.8 & 432 & 575 & 8.2 \\ ADF (g/kg DM) & 235 & 32.5 & 188 & 302 & 13.8 \\ ADL (g/kg DM) & 26 & 4.9 & 20 & 37 & 18.7 \\ TSC (g/kg DM) & 113 & 44.6 & 55 & 185 & 39.3 \\ Starch (g/kg DM) & 226 & 111.8 & 39 & 388 & 49.5 \\ PCDMD & 0.67 & 0.004 & 0.59 & 0.71 & 5.25 \\ \hline \end{tabular} \({}^{1}\) DM = dry matter; 2 SD = Standard deviation; 3 min = minimum value; 4 max = maximum value; 5 CV = coefficient of variation.  
\end{table} 
Table 1: Descriptive statistics (standard deviation (SD), minimum value (min), maximum value (max), and coefficient of variation (CV) for the ash, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), total soluble carbohydrates (TSC), starch contents, and pepsin-cellulase dry matter digestibility (PCDMD) within the set of samples (n = 18) analyzed in 1987. Figure 1: Visible and near/infrared second-derivative spectra for the average whole-maize forage samples stored frozen or at barn temperature over 29 years (**a**) and the differences between the average second-derivative spectra of the average frozen or barn-dried whole-maize forage samples (**b**). \begin{table}
\begin{tabular}{c c c c c c} \hline  & **1987** & **2016** & \multicolumn{3}{c}{**Significance**} \\ \hline  & & **BT 2** & **Frozen** & **SEM** & **SM 3** & **Time** \\ \hline Ash (g/kg DM 1) & 55 & 57 & 56 & 1.7 & ns 4 & **++-** \\ CP (g/kg DM) & 84 & 83 & 82 & 2.2 & ns & – 5 \\ NDF (g/kg DM) & 488 & 457 & 458 & 11.4 & ns & – \\ ADF (g/kg DM) & 235 & 231 & 233 & 7.9 & ns & – \\ ADL (g/kg DM) & 26 & 21 & 21 & 1.0 & ns & – \\ TSC (g/kg DM) & 113 & 81 & 93 & 10.4 & *** & *** \\ Starch (g/kg DM) & 226 & 225 & 233 & 32.2 & ns & ns \\ PCDMD & 0.67 & 0.67 & 0.68 & 0.008 & ns & ns \\ \hline \end{tabular} \({}^{1}\) DM = dry matter; 2 BT = barn temperature; 3 SM = storage method; 4 ns = non-significant (\(p>0.05\)); ** \(p<0.01\); *** = \(p<0.001\); *** = \(p<0.001\); 5 – = not tested.  
\end{table}