Dry Matter Determination in Animal Feed

Newsletter No. 72 - Item 5

The “Feed Management Education Project” is a program funded by the USDA and other partners in the United States. They have a full list of different “feed management” education documents.   One is published on Understanding Dry Matter in Animal Feed.

In animal operations, feed ingredients are provided to animals according to the weight of the feed. Although nutrients in ration formulations are often described in terms of a percentage, animals require actual amounts of nutrients.  This is known as the feeding rate and covered in greater detail as it relates to ostrich in The Basics of Ostrich Production Nutrition, Part 2, one of two papers presented at The World Ostrich Congress 2002, held in Warsaw, Poland.

As can be seen in reading both articles feeding individual feed ingredients according to weight is only accurate if the moisture content of the feed is the same as it was during the ration formation period. Changes in the weight of a feed due to changes in moisture alter the nutrient concentrations supplied to the animal unless appropriate adjustments are made to accurately reflect the actual nutrient concentration of the feed ingredient.

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Comparative Dry Matter of Different Feed Ingredients [source: Blue Mountain Feeds]

A variety of factors affect the moisture content of feeds. In many cases, the timing and method of harvest are the largest contributing factors to the moisture content of the feed. However, weather and environmental conditions, such as humidity, rain and snow, all affect feed moisture content. The graphic illustrates the variations between different types of ingredients.  The Green areas represent the minimum amount of dry matter, the shaded area illustrates the variations that can be experienced and the white is water.  The essential nutrients supplied by the feed - protein, energy, fat, fibre, vitamins, minerals are all contained in the Dry Matter.  The graphic therefore illustrates just how much greater weight of the total is required to be consumed to achieve the right nutrient intake as the moisture content increases.

Determining the Dry Matter content of feed provides a measure of the amount of a particular feed that is required to supply a set amount of nutrients to the animal. Increases or decreases in feed Dry Matter content result in over or under feeding of nutrients.  This is important with all animals, but particularly important with ostrich as a result of their low daily intake of feed in relation to their body weight, making them more sensitive to what may seem like minor errors or differences, when it comes to commercial levels of production.   The article Understanding Dry Matter in Animal Feed describes how to achieve this on farm with home produced grains and forage ingredients.

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