Fractionation and Evaluation of Carbohydrate and Protein Content of Some Concentrate Feeds for Ruminants

Chemical constituents and different fractions of carbohydrate and protein of fourteen concentrate feeds (six grains, five oil seed cakes and meals, three agro-industrial by-products) were evaluated. Average CP content was highest in oil seed cakes (38.3%) while NDF content was higher in by-products (41.0%). Total carbohydrate (CHO %) was higher in grains followed by oil seed cakes and by-products. Cotton seed cake (CSC) contained higher CHO% among oil seed cakes while wheat bran and deoiled rice bran (DORB) had similar CHO% among by-products. Similar trend was observed in non structural carbohydrate (NSC) content of test feeds. Starch content (% DM and % NSC) was highest in grains followed by by-products and oil seed cakes. Non protein nitrogen (NPN) content was lower in grains (0.6%) and by-products (1.2%). Soluble protein (SP as %CP) was highest in maize (43.7%), groundnut cake (56.3%) and rice polish (50.4%) among grains, oil seed cakes and by-products, respectively. Fast degrading carbohydrate (C_A) content was highest in oil seed cakes while intermediate degrading carbohydrate (CB₁) and slow degrading carbohydrate (CB₂) content was highest in grains and by-products, respectively. Instantaneously degrading protein (P_A) content was highest in oil seed cake whereas fast degrading protein (PB₁) content was comparable among three feed groups. Intermediate degrading protein (PB₂) and slow degrading protein (PB₃) content was highest in grains and by-products, respectively. It was concluded that due to lower content of unavailable carbohydrate (C_C) all grains, protein meals (soybean meal and guar meal) and wheat bran were superior feeds in terms of carbohydrate supply. Except for DORB and rice polish, all other feeds had more available protein making them good sources of protein for ruminants.