## 3 Results and Discussion
### Effect of Additive on Silage Characteristics  
Fermentation products (i.e., lactic acid, acetic acid, butyric acid, propionic acid, ethanol, and ammonia-nitrogen) in addition to the pH values of the silages were periodically measured throughout the 370 days of ensiling (Table 2). The concentration of NH\({}_{3}\)-N in all silages (data not shown) was less than 0.01 mg/L and was not significantly affected (\(p<0.05\)) by treatment, ensiling duration, and their interaction, indicating that there was no protein degradation [34]. In all silages, the concentration of butyric acid was below a detectable limit (<0.01), an indication of the absence of clostridia fermentation, and therefore adequate silage preservation was maintained [35]. Butyric acid fermentation brings about higher pH and TS losses compared to lactic or acetic acid fermentation, and therefore processes with high butyric acid concentration require a higher quantity of substrate for a given volume of BMP [36]. There were changes in the TS and VS content of all silages, as shown in Table 2. TS and VS contents were significantly lower (\(p<0.05\)) after the ensiling period compared to the initial values (time, t = 0), probably due to degradation to organic acids and alcohols. Losses in VS with duration of ensiling has also been reported by several authors [37; 38]. CTL silage had the lowest VS loss of 2.47% at the end of the ensiling period, while the losses in VS were 4.13, 4.07, and 3.76% in A50:1, B150:1, and C500:1 silages, respectively, indicating that VS loss increases with the elevated dosage of the additive, as also reported during the ensiling of maize [23] and sweet sorghum [39]. An important parameter used to evaluate the quality of silages is pH. Compared to the initial pH, there was a decline in the pH of the treated silages at day 30, unlike in CTL silage, wherein there was a slight increase, an indication that there was a faster production of lactic acid in the treated silages. However, neither treatment nor duration of ensiling had a significant effect (\(p<0.05\)) on the pH of the silages between days 30 and 120, during which there was a gradual decrease in the pH of all silages. However, the pH of all silages significantly decreased at day 370 compared to day 120, with no significant difference among the silages. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{4}{c}{**Substrates**} \\ \cline{2-5}
**Parameters** & **CTL** & **A:50** & **B:150** & **C:500** \\ \hline TS (\%FM) & 14.06 \(\pm\) 0.23 & 15.82 \(\pm\) 0.11 & 14.79 \(\pm\) 0.09 & 14.73 \(\pm\) 0.23 \\ VS (\%TS) & 79.08 \(\pm\) 0.34 & 79.99 \(\pm\) 0.21 & 79.03 \(\pm\) 0.22 & 77.84 \(\pm\) 0.14 \\ Acetic acid (g/L) & 3.2 \(\pm\) 0.02 & n.d. & n.d. & n.d. \\ Lactic acid (g/L) & 7.03 \(\pm\) 0.03 & n.d. & n.d. & n.d. \\ Butyric acid (g/L) & \textless{}0.01 & n.d. & n.d. & n.d. \\ NH4N (g/L) & 0.004 & n.d. & n.d. & n.d. \\ Hemicellulose (\%TS) & 10.78 \(\pm\) 0.21 & n.d. & n.d. & n.d. \\ Cellulose (\%TS) & 14.37 \(\pm\) 0.33 & n.d. & n.d. & n.d. \\ Lignin (\%TS) & 5.36 \(\pm\) 0.06 & n.d. & n.d. & n.d. \\ Crude protein (\%TS) & 17.54 \(\pm\) 0.01 & n.d. & n.d. & n.d. \\ Crude fibre (\%TS) & 11.37 \(\pm\) 0.07 & n.d. & n.d. & n.d. \\ WSC (g/l) & 75.36 \(\pm\) 0.13 & n.d. & n.d. & n.d. \\ Carbon (\%TS) & 37.5 \(\pm\) 0.31 & n.d. & n.d. & n.d. \\ Nitrogen (\%TS) & 2.93 \(\pm\) 0.03 & n.d. & n.d. & n.d. \\ Carbon/nitrogen & 12.80 \(\pm\) 0.22 & n.d. & n.d. & n.d. \\ Ash (\%TS) & 20.92 \(\pm\) 0.66 & 20.01 \(\pm\) 0.29 & 20.97 \(\pm\) 0.38 & 22.16 \(\pm\) 0.35 \\ pH & 4.98 \(\pm\) 0.02 & n.d. & n.d. & n.d. \\ \hline \hline \end{tabular} FM, fresh matter; TS, total solids; VS, volatile solids; CTL, control; NH4N, ammonium nitrogen; WSC, water soluble carbohydrate; A50:1, mixture of 1 g of additive and 50 g of sugar beet leaves; B150:1, mixture of 1 g of additive and 150 g of sugar beet leaves; C500:1, mixture of 1 g of additive and 500 g of sugar beet leaves. n.d, not determined.  
\end{table}