An Estimation for Total Digestible Nutrients in Fresh Herbage from a Perennial Ryegrass - White Clover Mixed Pasture

Abstract

The appropriate nutritional management of grazing dairy cows requires an accurate estimation of the content of total digestible nutrients (TDN) in fresh herbage from grazing pastures. The present study aimed to confirm the accuracy of existing estimations of TDN developed for fresh meadow fescue for perennial ryegrass (PR)-white clover mixed herbage, and to develop a new TDN estimation for PR-WC mixed herbage. The herbage was harvested from a PR-WC mixed pasture from April through October. A total of 16 Suffolk wethers were used for this study to evaluate the digestibility of the herbage. The TDN content of the herbage ranged from 68.9% to 77.7% dry matter (DM). The TDN estimated using the existing lignin-based model were similar to the actual TDN, whereas the existing organic b fraction (Ob)-based models underestimated the actual TDN. This may have been caused by high Ob digestibility due to high Ob content and the same level of lignin content in the herbage, as compared with those of meadow fescue. There were significant negative correlations between TDN content and acid detergent fiber (P < 0.01), lignin (P < 0.001), and Ob (P < 0.001) contents. These results demonstrated that the TDN content of PR-WC mixed herbage could be estimated accurately using the following estimations: TDN (% DM) =-4.33 lignin-0.39 cellulose + 94.64 (R 2 = 0.83, P < 0.001) or TDN (% DM) =-0.57 Ob + 93.39 (R 2 = 0.87, P < 0.001).

Model Pendugaan Total Digestible Nutrient (TDN) pada Hijauan Pakan Tropis menggunakan Komposisi Nutrien

“…Hal ini disebabkan oleh TDN merupakan sistem energi yang telah dikembangkan berdasarkan kandungan nutrien yang diperoleh dari analisis proksimat yaitu abu, PK, SK, LK dan BETN, tanpa memperhatikan adanya energi yang hilang saat dimetabolis ataupun untuk menghasilkan produk karena terbatasnya peralatan yang tersedia di laboratorium. TDN merupakan gambaran dari total energi yang berasal dari pakan yang dikonsumsi oleh ternak, dimana besar kecilnya nilainya tergantung pada kecernaan bahan organik pakan yaitu PK, SK, LK dan BETN (Mastopan et al, 2014;Nakano et al, 2018).…”

The Effect of Different Dietary Energy and Protein Sources on Blood Profile of Crossbreed Holstein Dairy Cows Raised in Small Stake Holder Farms

“…The samples of feed and feed residual were collected daily during the data collection period, dried at 55C in the oven for 48 hours, grounded to pass through a 1 mm screen using a Wiley mill. The feeds and residual feed samples were analyzed for Dry Matter (DM), ash, Crude Protein (CP), Organic Matter (OM), Total Digestible Nutrient (TDN, Nakano et al, 2018).…”

Production and Nutritional Values of Herbaceous Legumes in Tropical Climates of Indonesia

“…Crude protein, crude fat, and crude fiber have a relationship with TDN because TDN is an energy system developed based on nutrient content obtained from proximate analysis without considering the energy lost when metabolized or to produce products due to the limited equipment available in the laboratory. TDN is a description of the total energy originating from feed consumed by livestock, where the size of the value depends on the digestibility of the feed's organic ingredients, namely CP, CF, crude fat, and NFE (Mastopan and Hanafi, 2014;Nakano et al, 2018). The limitation of TDN is it does not consider detailed energy regarding the loss of nutrients burned during metabolism and the heat energy that arises when consuming feed (Ferrell and Oltjen, 2008;Jayanegara et al, 2017).…”