{"id":15508,"date":"2021-12-08T07:00:55","date_gmt":"2021-12-08T13:00:55","guid":{"rendered":"https:\/\/www.insta-pro.com\/?p=15508"},"modified":"2025-07-03T09:14:58","modified_gmt":"2025-07-03T14:14:58","slug":"tdn-how-useful-is-it","status":"publish","type":"post","link":"https:\/\/instapro.spinuhost.com\/en\/blog\/nutritionandtechnologies\/tdn-how-useful-is-it\/","title":{"rendered":"Total Digestible Nutrients (TDN): How Useful Is It?"},"content":{"rendered":"

There are many methods of evaluating ingredients for animal feeding.\u00a0 This is important because the composition and characteristics of the ingredients that make up a complete diet affect animal performance<\/a>, and diet costs are ~70% or more of total production costs.<\/p>\n

One evaluation method is called, \u201ctotal digestible nutrients<\/a>\u201d, or TDN, though it\u2019s popularity is waning, it still sees usage, especially in the beef industry.\u00a0 It\u2019s important to note that different versions of TDN exist<\/a> (see p. 13 and beyond)<\/a>, based on the type of ingredient in question, so it\u2019s important to understand which equation is being used when looking at the values.<\/p>\n

A TDN value is expressed as a percentage.\u00a0 The general calculations, of at least a few versions, are explained well in practice here<\/a>.\u00a0 The main idea is that the compositions and properties of major categories of nutrients are added up to give a score. \u00a0The categories are crude protein, crude fiber (or a specific measurement of fiber), fats and oils and nitrogen-free extract, each of which is individually corrected for total tract digestibility, while fats and oils, which are energy-rich, receive an energy factor correction.\u00a0 Essentially, as the total tract digestibility of any component increases, the TDN will increase.\u00a0 This will happen quicker with fats and oils due to the energy factor.\u00a0 A higher TDN means that more energy is available for growth, at least in theory.<\/p>\n

The benefits of using TDN are the following:<\/p>\n