Chemical Composition and In Situ Digestibility of Common Feed Resources for Ruminants in Marginal Uplands

Abstract

This study assessed the chemical composition and in situ degradation of predominant feed resources for ruminants in the marginal uplands of Inopacan, Leyte, Philippines. These feed resources included basal grasses such as guinea (Panicum maximum), humidicola (Brachiaria humidicola), and carabao grass (Axonopus compressus); supplemental legumes such as calopo (Calopogonium muconoides), madre de cacao (Gliricidia sepium) and centro (Centrocema pubescens); foliages of trees/shrubs such as jackfruit (Artocarpus heterophylum Lamk) and abgaw (Premna odorata); and concentrates such as rice bran (D₂) and squeezed grated coconut. Chemical analyses followed standard procedures, while in situ trial was done by incubating the feed samples in rumen-cannulated steer fed 70% basal/grass and 30% of the supplements.

Crude protein (CP) contents were 15.83 to 18.23% in legumes, 10.17 to 11.91% in tree foliages, 5.16 to 8.51% in grasses, and 4.84 to 6.08% in concentrates on as-fed basis. Gross energy (GE) contents were high – 5097 kcal/kg in grated coconut (highest) and 2931 kcal/kg in humidicola grass (lowest). Calcium (Ca) and phosphorus (P) contents were low, ranging from 0.004 to 0.189% Ca and 0.026 to 0.037% P. Considering animal requirements, these indicated a potential adequacy in GE supply but a limitation in protein and Ca and P in marginal uplands. Dry matter degradation (DMD) was high in grated coconut, agbaw, calopo and madre de cacao (77.76 to 86.51%) among the supplements and in carabao grass (71.11%) of the basal, and low in humidicola and rice bran D₂ (46.52 to 47.51%). Crude protein degradation (CPD) was highest in agbaw, calopo, madre de cacao, jackfruit and grated coconut (86.87 to 90.97%), moderate in guinea and carabao grasses and rice bran D2 (61.28 to 64.01%), and low in centro and humidicola (57.46 to 59.63%). Quantitatively, and across chemical composition and in situ degradation, the feeding of humidicola grass, centro legume, and rice bran D₂ is least recommended.