Dakota Farmer

Do genetically modified corn stalks have less feed value conventional corn stalks? Do cows like conventional stalks better than GMO stalks?

September 30, 2011

2 Min Read

You've probably heard both statements before. Are they fact or fiction?

"Fiction," says Jim Krantz, SDSU Extension specialist.

The majority of research conducted suggests there is no difference nutritionally between the two.  In addition, that same research indicates that there appears to be no difference in the preference of cattle for either hybrid.  Any difference that may appear visible may be due to the presence of additional corn on the ground or in the husk of non-GMO varieties.

As feed costs continue to represent up to 70% of cow production costs, corn stalks remain a viable alternative to higher cost, harvested feedstuffs.  Nutritionally, corn stalks can range from 65-70% TDN and 4-6% protein.  Those values may be near the high-end of these ranges, or higher, immediately post-harvest but will diminish with time.

The most palatable parts of a cornstalk are the husk and leaf.  Therefore, cows will consume those parts first and the cob and stem secondarily.  In order to determine the amount of forage available, the University of Nebraska devised a formula to determine this amount based on corn yield.  That formula is: Pounds of leaf and husk per acre = ([bushels per acre corn yield x 38.2] x 429) x 0.39.

Another "rule of thumb" method for determining forage available is that for each bushel of shelled corn produced per acre, 50 pounds of residue is available for grazing. (Ohio State University).

However, producers must remember that less than 50% of this residue will be available for cows due to losses caused by trampling and other waste.  Under most conditions, one acre of cornstalks will provide about 30-45 days grazing for a 1200 lb cow, although the total time is highly variable.

Strip grazing, accomplished by utilizing an electric fence, can extend grazing time and make the quality of the diet more uniform over the grazing period.  Cattle are thereby forced to consume stalks and cobs in addition to the husks and leaves..

With escalating feed costs remaining as a major challenge for cow/calf operations, cornstalks remain as a viable means to reduce that production cost.

Source: SDSU

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