Evaluation of various feedstuffs of ruminants in terms of chemical composition and metabolisable energy content

AIM: The aim was to determine the chemical composition and metabolisable energy (ME) content of feedstuffs used in ruminant animals using in vitro method. MATERIALS AND METHODS: A total of 18 feedstuffs used for ruminant feeding including cultivated non-leguminous fodders like maize, sorghum, pearl millet, and oat; leguminous fodders like cowpea and berseem; agro-industrial by-products such as wheat bran, deoiled rice bran, rice polish, wheat straw, and concentrates such as mustard oil cake, groundnut cake, soybean meal, cotton seed cake, grains like maize, oat, wheat, and barley were taken for this study. Chemical compositions and cell wall constituents of test feeds were determined in triplicate. The crude protein (CP) content was calculated as nitrogen (N) × 6.25. True dry matter digestibility (TDMD), true organic matter digestibility (TOMD), ME, and partitioning factor (PF) values were determined by in vitro gas production technique (IVGPT). RESULTS: The CP content of non-leguminous fodders varied from 7.29% (sorghum) to 9.51% (maize), but leguminous fodders had less variation in CP. Oilseed cakes/meals had high CP and ether extract (EE) content than other feedstuffs except rice polish, which had 12.80% EE. Wheat straw contained highest fiber fractions than the other ingredients. ME content was highest in grains (wheat-12.02 MJ/kg) and lowest in wheat straw (4.65 MJ/kg) and other roughages. TDMD of grains and oilseed cakes/meals were higher than the fodders and agro-industrial by-products. The same trend was observed for TOMD. CONCLUSIONS: It was concluded that the energy feeds showed a great variation in chemical composition and ME content. The results of this study demonstrated that the kinetics of gas production of energy feed sources differed among themselves. Evaluation of various feedstuffs is helpful in balanced ration formulation for field animals and under farm conditions for better utilization of these commonly available feed resources.