Chemical Composition, Available Forage and Leaf Area Index of 17 Genotypes of Elephantgrass (Pennisetum purpureum Schum.) under Grazing, at Campos dos Goytacazes, RJThe assay was conducted from October 1998 to January 1999 in the cropgrass section of the Universidade Estadual do Norte Fluminense in Campos dos Goytacazes, RJ. The levels of crude protein, neutral detergent fiber, acid detergent fiber, the forage yield and the leaf area index (LAI) were evaluated in 17 genotypes of elephantgrass (Pennisetum purpureum, Schum.), fifteen new clones of elephantgrass: CNPGL 91-19-1, CNPGL 91-10-5, CNPGL 91-27-5, CNPGL 91-02-5, CNPGL 91-01-2, CNPGL 91-13-2, CNPGL 91-25-3, CNPGL 91-10-2, CNPGL 91-02-4, CNPGL 91-11-2, CNPGL 91-34-1, CNPGL 91-27-1, CNPGL 91-28-1, CNPGL 91-06-3, CNPGL 91-17-5 and two cultivars, MINEIRO and TAIWAN A-146, from the BAGCE of the Dairy Cattle Research Center - EMBRAPA. The elephantgrasses were submited to grazing, in the rainy season, by lots of 10 to 13 dry cows with average live weight of 500 kg, during a period of 1 to 2 days. The genotypes CNPGL 91-01-2, CNPGL 91-10-2, CNPGL 91-25-3, CNPGL 91-10-5 and CNPGL 91-27-5 showed greatest percentage of crude protein, and smaller values of neutral detergent fiber and acid detergent fiber. In general, the chemical composition was negatively affected by period after period of grazing. No differences were found in the forage dry matter yield of the genotypes. The genotypes CNPGL 91-02-5 and CNPGL 91-11-2 presented utmost LAI of 7.08 and 6.67, respectively. Differences were found from the first to other grazing periods, as to dry matter production as to leaf area index.
acid detergent fiber; crude protein; dry matter production; grazing periods; leaf area; neutral detergent fiber
