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Reducing nutrient shrink in your rations

Robin Rastani Published on 28 June 2013

With feed prices high, many nutritionists and producers have become focused on reducing shrink of feed ingredients on the dairy (i.e., reducing waste of feed).

However, these discussions frequently focus around the total volume of feed and do not take into account the nutrients within the feed.



When the maximum amount of nutrition cannot be utilized from the ration as fed, it is a form of waste or “shrink.” This is what I refer to as nutrient shrink.

Nutrient shrink commonly occurs in three ways:

  1. Feeds are fed before the maximum amount of nutrition can be extracted efficiently from them. An example is when corn silage is fed before the prolamin matrix is broken down.
  2. Feeds are fed without adequate preservation of the nutrients (i.e., unsaturated fats without an antioxidant). Unsaturated fatty acids are broken down, or oxidized, when they are exposed to air.

    This is more pronounced in the summertime and is one of the key causes of heating of the feed at the bunk (the other cause is growth of yeasts and molds).

    The breakdown of the fat leads to a reduction in the amount of energy that can be utilized by the cow.

  3. Increased dry matter intake results in increased rate of passage. As a result, the substrates in the feed are not in the GI tract long enough to have the nutrients extracted from the feed completely.

When feed prices were lower, the occurrence of nutrient shrink was accepted; nutritionists made adjustments and moved on. As long as the cows were producing enough to be profitable, life was good.


However, now with corn at $7 per bushel and soybeans at $15 per bushel, profit margins are much tighter on the dairy. Thus, nutritionists and producers are evaluating how to get more production out of less feed. One solution is to reduce nutrient shrink.

Most nutritionists equate reduced nutrient shrink to an increase in feed efficiency. Essentially, reducing nutrient shrink improves your herd’s feed efficiency without increasing feed costs more than a few cents or decreasing production.

Solutions to reduce nutrient shrink include:

  1. Plan ahead. Increase your inventory of corn silage so that in time you’re feeding out less and less of the corn silage before it is fully fermented and the prolamin matrix has broken down (usually four months after ensiling).

    Producers who do this can save considerably as they do not need to supplement extra energy and starch.

  2. Feed a dietary antioxidant. Research shows that feeding a dietary antioxidant can improve fat-corrected milk when unsaturated fat (on a dry matter basis) is between 2 and 3.5 percent of the diet.

    The reason for this is that the antioxidant protects the unsaturated fats from breaking down, and more energy is available for the cow to put toward productive functions.

  3. Control dry matter intake by supplementing fiber. This fiber can be from non-forage fiber sources like soybean hulls, cottonseed hulls and almond hulls. The goal is to slow down the rate of passage so that production can be maintained from less feed (i.e., less nutrient use).

I challenge you all to measure your feed efficiency and try to improve it without increasing feed costs or decreasing production. If you are able to do so, you have successfully reduced nutrient shrink on your dairy. PD


Robin Rastani
  • Robin Rastani

  • Dairy Technical Managert
  • Novus International
  • Email Robin Rastani