HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Johnson, W. L. Articles by Pezo, D. Search for Related Content PubMed Articles by Johnson, W. L. Articles by Pezo, D.

Cell-Wall Constituents and In Vitro Digestibility of Napier Grass (Pennisetum Purpureum)¹

North Carolina State University, Raleigh 27607 and National Agrarian University, La Molina, Lima, Peru

Abstract

Growth stage and seasonal influences on the chemical composition and in vitro digestibility of napier grass (Pennisetum purpureum) were studied in the sub-tropical desert climate of Peru's central coast. Important seasonal differences in the effects of plant maturity were noted. Dry matter concentration, steadily increasing with maturity, was generally higher in summer and lower in winter, compared with other seasons. The expected decline in crude protein with maturity was more rapid in the warmer seasons than in winter. Likewise, the levels of total cell-wall constituents (CWC), acid-detergent fiber, and cellulose increased more rapidly in the warmer seasons than in winter. The CWC fraction was less digestible in winter than in spring or fall, but in vitro true digestibility of dry matter (DMD) was lower in summer than in other seasons at comparable ages of the forage. Using CWC and lignin levels to predict %DMD resulted in a coefficient of determination equal to 0.79; holocellulose or lignin plus silica fractions were less reliable predictors of digestibility.

The results demonstrate the desirability of early utilization of napier grass grown under Peruvian coastal conditions, at no later than 12 weeks of age in summer but at possibly slightly longer intervals in winter. Excess summer forage possibly could be carried over in the field for winter use, but winter and spring forage should be harvested before the onset of summer.

¹ Paper No. 3970 of the Journal Series of the North Carolina State University Agricultural Experiment Station, Raleigh. Research supported by the North Carolina State University Agricultural Mission to Peru (USAID Contract) and the Forages Program of the National Agrarian University.

² Former student of the National Agrarian University.

³ Formerly Research Assistant, Forages Program, National Agrarian University; Present address, HCA-CTEI, Apartado 63, Turrialba, Costa Rica.