Maximize Corn Silage Quality to Maximize Milk Production

By Bill Seglar

Dial-In desired fiber digestibility in silage by adjusting cutting height

The Pioneer Nutritional Science team suggests that dairymen can "dial-in" the type of corn silage they need by adjusting chopping height. If high neutral detergent fiber digestion (NDFD) is desired for high milk production rations, one can achieve brown mid rib-like (BMR) values with conventional hybrids and still have more yields without having to incur the agronomic risk associated with current BMR genetics.

Hybrid 33J56 F697
Height 18 inch 6 inch
Yield, tons/acre 21.3 16.2
% NDFD, 24=hr. 44.3 43.4
Lbs. Milk/Acre 15,113 12,620

A Pioneer field study conducted in Pennsylvania compared Pioneer brand® 33J56 to Mycogen F697 BMR at 6 and 18 inch cutting heights. The table at the right shows that the digestibility of fiber for Pioneer hybrid 33J56 cut at 18 inches was equal to Mycogen F697 cut at 6 inches. The resulting yield still was 31% greater. This proves that dairymen and nutritionists wanting higher fiber digestibility in corn silage can be obtained from a conventional hybrid like 33J56 that possesses strong agronomic and yield traits.

Digestibility fiber in this field trial was based on a 24-hour NDFD determination within Pioneer and is why the values appears lower than values based on 48-hour NDFD from commercial laboratories.

Improve fiber digestion by treating with Pioneer® brand 11CFT inoculant

The Pioneer Nutritional team suggests that dairymen can further enhance fiber digestion of conventional hybrids beyond high cutting by inoculating with Pioneer® brand 11CFT Inoculant. Pioneer research studies show NDF digestion increases 4 to 7 percentage points with 11CFT.

High digestible fiber corn silages need special adjustments in the ration

Dairymen transitioning from prior to current year corn silages need to monitor starch and NDFD digestion differences between the two forages. From a hybrid genetic selection standpoint, starch usually will range from about 23-30% and NDFD (at 48-hours) from 56-60%. However environmental growing and harvest conditions can make the starch range broaden 10-40% and NDFD by 45-70%.

Droughty conditions usually results in high NDFD values; often a conventional hybrid will feed like a brown mid-rib hybrid. Below are feeding recommendations when NDF digestion approaches 65-60%:

  1. Increase forage levels and decrease fermentable carbohydrates to achieve a 55:45 forage to grain ratio.
  2. Increase NDF up to 32-35%.
  3. Increase NSC (non-soluble carbohydrates) up to 37-38%.
  4. Increase soluble protein up to 32-36%.
  5. Maintain a ratio of 1# crude protein for every 4.3-mcal net energy.
  6. If fat is fed, increase calcium levels up to a minimal 1.0% and magnesium up to 0.3%.
  7. If particle lengths are short, add 2-4# dry hay in the ration to achieve proper effective fiber levels.

Examine Corn Silage Data Compilation for July 2002-October 2002

The information below is provided by Dairyland Laboratories in Arcadia, Wis., and shows how key nutritional and digestibility traits vary in corn silages from the 2001 and 2002 crop years. The very low 16% starch probably is reflective of harvesting a 2001 drought stressed crop at early maturity while the 45% starch is probably reflective of a 2002 elite hybrid growing in ideal growing conditions. High starch content will have inversely low NDF values.


Normal Range



NDF (%)






Starch (%)






NDFD, 48 hr (%) 49.1





IVTDMD, 48 hr (%)






NEL - SSCSE Processed (%)






NEL - SSCSE Unprocessed (%)






Milk per ton






Usually NDFD, 48-hour values of 70% are reflective of BMR genetics. However as mentioned above, conventional hybrids can achieve high NDFD also due to drought stress, high chopping the crop, and inoculating with 11CFT.

Corn silage that is processed usually has increased NEL (net energy for lactation) values over non-processing due to corn-grain rolling making starch more available to the rumen. The SSCSE (Schwab-Shaver Corn Silage Equation) is especially sensitive to energy differences from processing when harvest maturity is advanced and dry matters are high; this is when corn grain will have harder starch texture.

The SSCSE is used in the MILK200 equation, which was developed by researchers at the University of Wisconsin to predict milk/ton. MILK200 inputs include percent:

  1. dry matter
  2. crude protein
  3. NDF
  4. NDFD
  5. starch
  6. ash
  7. fat
  8. kernel processing score and
  9. yield (tonnage)

The equation allows producers to compare how two different corn silages might feed based on these inputs.

For reproduction permission, contact:
Bill Seglar
Ph: 515-334-6674
Bill Mahanna
Ph: 515-334-6673

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