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\hypersetup{pdftitle={Compositional Changes of Maralfalfa"=grass (\textit{Pennisetum purpureum}\,$\times$\,\textit{Pennisetum glaucum}) after Regrowth in the Colombian Highlands},pdfauthor={Fánor Casierra Posada, Edwin Gámez, Carlos Berdugo},pdfsubject={Tropentag 2010: Abstract},pdfkeywords={ fodder, animal nutrition, dry matter, growth curve, hemicellulose, lignification},pdfpagemode=None,colorlinks=true}
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\parbox[b]{13.4cm}{\centering \large{\textbf{Tropentag, September 14-16, 2010, Zurich}}\\[1ex] \Large{``World Food System  ---\\A Contribution from Europe''\\[2ex]}}
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\Large{\textbf{Compositional Changes of Maralfalfa"=grass (\textit{Pennisetum purpureum}\,$\times$\,\textit{Pennisetum glaucum}) after Regrowth in the Colombian Highlands\footnote{\textbf{Contact Address:} Fánor Casierra Posada, Pedagogical and Technological University of Colombia, Faculty of Agricultural Sciences - Plant Ecophysiology Group, Carretera Central del Norte km 1 Vía a Paipa, Tunja, Colombia, \mbox{e-mail}: \email{fanor.casierra@uptc.edu.co}}\\[0.8ex]}}
\normalsize{\textsc{Fánor Casierra Posada$^{1}$, Edwin Gámez$^{1}$, Carlos Berdugo$^{2}$}}
\end{center}
\begin{itemize*}
\item[]{\small{\textit{$^{1}$Pedagogical and Technological University of Colombia, Faculty of Agricultural Sciences, Germany}}}
\item[]{\small{\textit{$^{2}$University of Bonn, ARTS International Master Programm, Germany}}}
\end{itemize*}
\index[author]{Casierra Posada, Fánor}
\index[author]{Gámez, Edwin}
\index[author]{Berdugo, Carlos}
\begin{center}
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\textbf{Abstract}
\begin{abstract}
\normalsize{
Few high yield forage species for cold areas in Colombia are available. Low productive potential pastures are cultivated in most cold areas in farms dedicated to milk production. The areas of greatest potential productive grasses such as kikuyu"=grass (\textit{Pennisetum clandestinum}) and ryegrass (\textit{Lolium perenne}) have increased in recent years. The high performance maralfalfa"=grass (\textit{Pennisetum} sp) was recently introduced as cutting to use grass in dairy cattle feeding for partial or total replacing kikuyu"=grass or ryegrasses. To evaluate the effect of cutting age on nutritional value of maralfalfa"=grass, a plot study was done in Chinavita / Colombia. Samples of this grass were collected from the same paddock at 50, 70, 90, 110 and 130 days after regrowth (dar) and the following parameters were analysed: leaf area, dry matter, organic matter (\%), crude protein (N\,$\times$\,6.25), neutral detergent fiber (\%), acid detergent fiber (\%), hemicellulose (\%) and fat content (\%). Treatments were replicated three times in a randomised block design. Data were subjected to analysis of variance, using general linear models procedures of SPSS statistical package. At each interval organic matter and crude protein content declined significantly ($p < 0.05$). Leaf area, dry matter, ash content, acid and neutral detergent fiber were increased after regrowth as shoots became older. The highest value for fat content was observed at 70 dar, later, it was reduced to 130 days. Hemicellulose content in grass increased from 50 to 90 dar, and then it declines to 130 dar. This study showed that the quality of maralfalfa"=grass becomes less favourable with advanced maturity. This could be due to increased and accumulation of dead tissue and the lignification of the cell walls. Although in the region where this study was conducted, maralfalfa"=grass is harvested at 110 dar, current results suggest that in order to optimise nutritive value, it should be harvested between 70--90 days after regrowth.}

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\noindent \textbf{Keywords:}  fodder, animal nutrition, dry matter, growth curve, hemicellulose, lignification
\index[key]{ fodder}
\index[key]{Animal!nutrition}
\index[key]{Dry matter}
\index[key]{Growth!curve}
\index[key]{Hemicellulose}
\index[key]{Lignification}
\end{document}