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Where to Look!- Reading a Feed Analysis

Here is an example of a feed analysis performed on lentil bales. Feed analysis sheets are very complicated with a lot of abbreviations. However, a lot of the numbers and abbreviations are only a priority for a nutritionist. There are very few values that a producer needs to know. Values like the mineral contents of feed are important to both nutritionists and producers as these are important values to meet the nutritional needs of cattle and to prevent toxicity or deficiency. The dry matter content illustrated the sample with no moisture content and helps to determine more accurate nutrient measurements in the feed. Crude protein, acid detergent fiber (ADF), neutral detergent fiber (aNDF), crude fat, and total digestible nutrients (TDN) are the most common used values when formulating diets. I have listed a few of these values with descriptions under the picture, to promote understanding of how the value of a feed product is calculated. There are complex laboratory procedures to determine these values. Hopefully in the next few weeks I will have time to make a few blog posts explaining how each of these nutrients are digested and utilized within ruminants.


Crude Protein

  • Estimated based on nitrogen content in feed, measures both true protein and non-protein nitrogen

  • Broken into soluble fractions, insoluble fractions, and indigestible fractions (found in feces)

ADF- Acid Detergent Fiber

  • Form of fiber that has a very low digestibility

  • Contains plant components such as cellulose, lignin, and insoluble minerals

aNDF- Ash-Free Neutral Detergent Fiber

  • Predictor of voluntary intake because it provides bulk or fill

  • Measures most of the structural components in plant cells

  • Unfortunately this often includes measurements of soil contamination (silica) because they do not dissolve in neutral detergent

Lignin

  • Type of fiber that cannot be digested by monogastrics (single stomach) or ruminants (multi-stomach)

  • Content increases as plant matures

Ash

  • Mineral content estimate

  • Combustible material in feed is burned off in furnance, leaving inorganic matter (ash) which contains minerals

TDN- Total Digestible Nutrients

  • Uses values from proximate analysis to estimate energy content

  • Expressed as a percentage and takes into consideration the digestibility of crude protein, crude fiber, lipids, and carbohydrates

  • Factors affecting TDN include dry matter (DM) content, digestibility of the DM, amount of fat (higher fat=higher TDN), and the species fed

ME- Metabolizable Energy

  • Accounts for energy losses arising from absorption and metabolism of the feed

  • Urinary energy loss, gaseous energy loss, gill energy loss and fecal energy loss