Proximate Nutrient Composition of 10 Tropical Forage Grasses

Abstract

Ten tropical forage grasses (Pangola, Digitaria decumbens; Congo, Brachiaria ruziziensis; Signal, Brachiaria brizantha; Buffel, Cenchrus ciliaris; Guinea, Panicum maximum; Jaragua, Hyparrhenia rufa Giant Pangola, Digitaria valida; African Crab, Digitaria swazilandensis; Venezuelan Elephant, Pennisetum setosum; and Lampo, Hemarthria altissima), lightly fertilized with NH₄NO₃ at the rate of 350 kg/ha, were harvested by hand (machete) every 30 days during 180 days, beginning on August 20, 1970, at the College of Agricultural Sciences grass collection, University of Puerto Rico at Mayagüez. Total dry matter (TDM) content was calculated. Forages studied were evaluated chemically for crude protein (N X 6.25) (CP), crude fiber (CF), ether extract (EE) and ash (A). NFE was calculated as the difference between 100 and the sum of CP, CF, EE and A. Statistical analyses of variance were conducted. All fractions differed in a highly significant way with respect to species and plant age. Highly significant differences in CP, EE and A at decreasing rates and in TDM, CF and NFE at increasing rates were obtained, as the grasses advanced in maturity. The largest changes in forage quality occurred between 30 and 60 days of age.