Guidelines for Adequate Forage and Fiber Consumption

Dairy Pipeline: April 1999

Charles C. Stallings
Extension Dairy Scientist, Nutrition
Virginia Tech
(540) 231-4758
cstallin@vt.edu

Here are some guidelines to ensure adequate forage and fiber consumption. Cows must chew and ruminate in order to break down structural parts of the diet. Fiber is the primary structural part of a cow's diet and is mainly supplied by forages. During the process of chewing the cow secretes saliva which buffers the rumen to acids produced during fermentation. A cow that does not chew enough is prone to a condition called acidosis which can result in reduced feed consumption, low milk fat test, and lame cows. Generally cows should consume a minimum of 2% of body weight as forage dry matter. Lactating cows usually will consume dry matter at 3 to 4% of their body weight. Therefore, forages will normally make up half or more of the total dry matter consumed. There can be exceptions. High fiber feeds such as whole cottonseeds, cottonseed hulls, and certain other alternative feeds can replace some of the forage in the ration. Guidelines are to supply 19 to 21% acid detergent fiber and 28 to 32% neutral detergent fiber (NDF) in the ration dry matter. In addition NDF from forage should be fed at .9% of body weight, probably higher for rations formulated with low fiber corn silage. Forages should not be finely chopped or ground and particles should be coarse enough to stimulate chewing. Silage should be a minimum of 3/8 inch theoretical cut and higher for kernel processed corn silage (3/4 inch has been suggested). When fiber is marginal in the ration _ to _ pound per cow per day of buffer (sodium bicarbonate) might be advisable. Remember to keep cows chewing to ensure health and a productive animal.

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