By James B. Neel
Using corn crop residue as winter feed for dry, pregnant beef cows is one way that producers can reduce feed costs. In Tennessee, for example, grazing corn crop residue is probably the least used feed resource available to cow-calf producers. It is an excellent feed source and can lower winter feed bills more than the amount of money spent for hay and other winter feed sources.
In a Nebraska study, an acre of stalks contained a total of 6,780 pounds of dry matter, including 5% corn grain; 21% cobs; 41% leaves and husks; and 33% stalks. Although these figures will vary by plant population, harvesting equipment and the grain yield, it is safe to assume that about two-thirds of the field will contain usable cattle feed.
The carrying capacity of an acre of stalk fields is about 45 days for the average cow, but it may be less for larger cows. Producers can use the fields more effectively if about one-fourth acre per cow is allowed during the first week and an additional one-fourth is added each week thereafter. Cows will eat the best material first and the rest later. Condensing grazing will force them to use all of the material on the field. Portable electric fencing, such as polywire, would be very useful in keeping the cows where you want them.
Very few nutrients are taken by the grazing cow from the field. Nebraska workers found that a cow gaining 80 pounds will take only three-fourths of a pound of actual nitrogen from the field. Most is returned to the field as feces and urine. Stalk fields are nutritionally adequate for most mature beef cows in mid-pregnancy. Young animals or cows calving early in the winter would require about one-half pound of additional protein in the daily ration.
Neel is a University of Tennessee Extension beef cattle specialist.