A great deal of interest has been generated recently in cutting corn silage higher to improve forage quality. Leaving the less digestible, lower part of the corn plant does produce higher-quality silage, but also reduces yield.  Is the improved quality large enough to offset the yield loss?

PennsylvaniaStateUniversity researchers Zhiguo Wu and Greg Roth analyzed a pool of data to answer that question. The collective results of 11 cutting-height studies (with cutting height ranging from 7 inches for “low cut” to 19 inches for “high cut”) lead the researchers to draw the following conclusions:

  • Dry matter (DM) and starch content increased about two percentage units each, and ADF and NDF content decreased by 7 to 10 percent, for high-cut silage.
  • Yield for high-cut silage was reduced an average of 7.3 percent.
  • Estimated milk per ton of silage increased slightly for high-cut silage, but milk per acre decreased slightly.
  • Milk production per cow increased 3 lbs. /day for high-cut silage, but this increase was offset by the effect of lower milk fat percentage (0.3 percent) on the paid value of milk. 

The researchers noted that leaving more crop residue in the field could help increase soil erosion protection.  Cutting higher also allows for earlier harvest, so it could be used as a timing tool when working with custom harvesters.  Nitrate content also is likely to be reduced in higher-chop silage, an important consideration in drought years. On the other hand, specialty hybrids such as brown midrib corn may change little in quality in the lower stalk portion, negating the benefits of higher chopping.  They concluded that higher chopping can be a tool to manage dry-matter content and harvest timing of corn silage, but that the practice’s advantages were not absolute.  To read the researchers’ complete analysis, follow this link (PDF format).