Abstract

    A study was undertaken to evaluate the nutritional quality of some conventional and non-conventional feed resources by using in vitro gas method. Samples of various feedstuffs were analyzed chemically, as well as by in vitro gas method. The feedstuffs having different digestibilities showed significant (P<0.05) differences in the rate and amount of gas production, metabolizable energy (ME) and digestibility of organic matter. Predicted metabolizable energy values were very low in feedstuffs having high fiber and low protein contents. These feedstuffs included various grasses, crop residues and wheal straw. Lowest ME value of 4.7 MJ/kg of dry matter (DM) was found in wheat straw. Many of the roughages (Sorghum vulgare, Kochia indica, Leptochloa fusca) studied were found to be deficient in fermentable carbohydrates, resulting in low organic matter digestibility. Concentrate feed stuffs like cotton seed meal, sunflower meal, cotton seed cakes, rice polish, rapeseed meal and Zea mays (maize) grains had higher ME values (9.27 – 12.44 MJ/kg DM). The difference of ME of various feedstuffs reflects different contents of fermentable carbohydrates and available nitrogen in cereals and protein supplements. Among the non-conventional feedstuffs, Acacia ampliceps, Acacia nilotica, Sesbania aculeata, Leptochloa fusca and Prosopis juliflora were found potential fodders. Extensive use of in vitro gas method proved its potential as a tool to evaluate various ruminant feeds for energy component.