|Green and Growing|
|Written by D. Bruce Bosley, CSU Extension Agent/Cropping Systems|
Grazing standing corn eliminates the costs of harvesting, transporting, drying and storing grain. Expenses for cutting stalks for hay or chopping silage also are avoided. Plus, letting cattle do the harvest eliminates yardage expenses, manure hauling and feed processing and handling.
However, care should be taken anytime one uses stressed crops for feeding livestock to avoid nitrate, other toxicities and other digestive problems.
After a brief learning period, cattle will preferentially graze corn ears if any have developed. Drought-damaged corn may not have many ears, but if much grain has developed, the cattle first need to adapt to a higher grain diet before grazing corn begins. Otherwise, acidosis or other digestive disorders could develop.
Cross-fencing and strip-grazing is needed to minimize trampling waste.
Give cattle access to no more than a two-day supply of fresh corn at a time; a one-day supply is even better, especially for younger, growing cattle. Dry cows might do fine if moved just twice each week.
Electric fence is used most commonly for cross fences, but animals must be trained to respect these fences before entering the corn field. Driving over a strip of corn with a tractor, pickup or four-wheeler before placing the fence in the strip makes it easier to set up the fence and visually alerts the cattle that the fence is nearby. Constructing multiple strips ahead of time provides a catch area if the original fence fails to keep animals in the desired smaller area.
Standing corn can be limit-fed to stretch the supply and/or to minimize over-conditioning by reducing the area allotted to the cows and forcing them to eat more of the lower quality stalks. However, nitrate concentration may be high in the lower portion of the corn stalks. Before forcing animals to consume this part of the plant, test the stalks for nitrates and then manage accordingly.
In addition, limit-feeding can cause animals to remain hungry even when they have consumed sufficient protein and energy to meet their needs.
Behavior problems can occur, including increased pressure on fences. More strands of wire, higher electric voltage or providing free choice access to poor quality hay or straw may be needed to avoid problems.
Instead of grazing standing corn, corn can be windrowed first and then cattle can be allowed to graze the windrows. This may simplify construction of fences and determination of area to be allotted.
Trampling waste also can be reduced. However, if cattle do not utilize all of the corn in the windrows, the remaining residue might cause problems for planting crops next spring.
Also, residue remaining after grazing will be concentrated in the windrows, which may not meet residue requirements for conservation purposes, compared to grazing standing corn.
Holyoke Enterprise Aug. 9, 2012