Starch digestibility of common feedstuffs can have a significant impact on performance of lactating dairy cows.

Pat Hoffman and Randy Shaver, dairy scientists at the University of Wisconsin-Madison, have compared the starch digestibility values of very fine-ground corn to cracked corn. They wrote that a "14 percentage unit difference in starch digestibility would translate into a 10 percentage unit difference in the TDN values for these corns ... At a 10 lb. dry matter per cow per day feeding rate of corn, failure to account for this difference in energy values could cost about 3 lb. of milk per cow per day."

Starch digestibility can be influenced by many factors, including particle size, moisture, maturity, ensiling and virtuousness. There are a number of analytical tools available for determining starch digestibility.

In September, Dairyland Laboratories Inc will host a series of technical-update seminars that focus on starch digestibility. The guest speaker will be the aforementioned Randy Shaver. Information presented will provide nutritionists with a good understanding and practical application of the following analytical tools:

  • In vitro Starch Digestibility 7 hr.
  • Total Tract Starch Digestibility (Cow Relevant analysis).
  • Fecal Starch.
  • UW Grain Evaluation System.

For a complete listing of dates and times, please visit