Free choice minerals for dairy cows?

Dairy Pipeline: January 1996

by Charles C. Stallings
Extension Dairy Scientist, Nutrition
Virginia Tech

This issue keeps coming up and recently was addressed on Dairy-L, the Dairy Discussion List on the World Wide Web. I have always recommended that minerals and vitamins be force fed with other feeds when possible. However, when supplemental feeds are not offered it may be necessary to supply a complete mineral with a salt base to regulate consumption. This situation might occur when heifers or dry cows are being maintained on pasture. If you are supplementing adequately you do not need the free choice minerals. It is simply an added expense. What about sodium bicarbonate free choice? Some nutritionists are recommending offering bicarb free choice in addition to including 4 to 8 ounces in the ration. Testimonials indicate cows have the ability to consume more in response to a need such as a low fiber ration. Sodium bicarbonate is offered as a buffer not as a source of nutrients, so it is different than the typical free choice mineral mix. While research is not available to support testimonials there may be some merit in the practice, but it is impossible to know until controlled studies have been conducted. Another suggestion was to feed sodium bentonite free choice when free choicing sodium bicarb. Some cows prefer bentonite to bicarb and this might serve to prevent the soil or dirt craving cows have (no, you are not the only one who has cows that eat dirt). Also bentonite usually is cheaper than bicarb. Prevent sodium bentonite consumption of more than a pound per cow per day. Cows may have the ability to ingest certain compounds that improve the way they feel (prevent an acid rumen), but there is no data to show that they can choose feeds that supply a needed nutrient.

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