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Wildcat Extension District

Livestock News Column


Testing Hay Can Save Supplement Dollars

Forage analysis can be a useful tool to determine the nutrient value of hay fed to animals this winter. Knowing the protein and energy content of harvested forages enables cattlemen to better match their purchased supplements with what is needed to meet the nutritional needs of the cows being fed.

Forages that are higher in quality as measured by crude protein also have higher energy levels. Just as important, higher quality forages are more rapidly digested in the rumen and as a result intake is greater when forage quality increases. For example expected consumption by a beef cow of low quality forages (below about 6% crude protein) will be about 1.5% of body weight (on a dry matter basis) per day. Medium quality grass hays (above 8% crude protein) may be consumed at about 2.0% of body weight.  Excellent forages, such as good alfalfa, silages, or green pasture may be consumed at the rate of 2.5% of body weight per day.  The combination of increased nutrient content AND increased forage intake makes high quality forage very valuable to the animal and the producer.

The value of forage testing can best be illustrated by comparing the supplement needed to meet the nutrient needs of cows in the winter. A 1,200 pound spring-calving cow in late gestation needs 1.9 pounds of crude protein in her diet each day to meet her needs and that of the growing fetus. If only offered hay that is 5% crude protein on a dry matter basis, her expected intake would be 1.5% of body weight or 18 pounds of dry matter, resulting in a crude protein intake of .9 pounds per day leaving the cow deficient one pound of crude protein daily. In the same situation if the cow was offered 10% crude protein hay her expected intake would increase to 2% of body weight or 24 pounds, resulting in daily crude protein intake of 2.4 pounds which meets her protein requirement. A protein supplement would be needed for the cow on 5% protein forage, while no supplement is needed on the cow receiving 10% protein forage.

The only way to accurately determine the protein and energy content of harvested forages is through forage sampling. For forage sample results be useful a representative sample of the forage lot must be submitted. As a rule of thumb collect core samples from 20% of the bales in a lot. A forage sampler is available to be checked out from all three Wildcat District offices in Altamont, Girard, and Independence.

For more information about forage sampling and/or supplementation contact me at the Altamont office at (620) 784-5337 or email me at rkmartin@ksu.edu  For other resources available through our staff check out www.wildcatdistrict.ksu.edu, https://www.facebook.com/Wildcat.Extension.District or https://twitter.com/wed_livestock

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Keith Martin
Livestock Agent
Wildcat Extension District
(620) 784-5337


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