Once the combine pulls out of a cornfield, it’s often the case that field harvest is only partially accomplished. Cattle on cornstalks is going to become a common sight over the next several months and getting the most out of the plant residue involves some planning.
In the University of Nebraska’s BeefWatch newsletter, Aaron Berger, a beef systems extension educator based in Kimball, Neb., recently outlined some of the keys needed to get the most grazing potential out of cornstalks. They are:
1. Scout fields prior to grazing to determine the amount of corn present and to look for piles that could cause grain overload, which can result in bloat or death in cattle. If there is more than eight to 10 bushels of corn grain per acre on the ground, implement a grazing strategy to control corn intake.
2. Base stocking rates on corn bushel yield per acre and the average weight of cattle that will be grazing. A “Corn Stalk Grazing Calculator” spreadsheet developed by the University of Nebraska can be used for these calculations. It is also available as a component of a mobile app called NUBeef-cowQlate.
3. A quick way to estimate grazing days per acre available for a 1,200-pound nonlactating cow is to take corn bushel yield and divide by 3.5. For example, 180 bushels per acre divided by 3.5 equals 51 grazing days per acre.
4. Quality of grazing starts high at approximately 70 percent total digestible nutrients (TDN) and then drops to a low of 45 percent TDN at the end of the grazing period. The rate of quality decline is dependent on stocking rate and environmental factors such as moisture and field conditions.
5. Mature, nonlactating, spring calving cows with a body condition score of 5 or better will not need protein supplement when grazed at recommended stocking rates.
6. First-calf heifers in the 90 days prior to calving will need protein and energy supplementation to meet nutrient requirements. Feeding 3 to 5 pounds per head per day of dried distillers grains would meet this need.
7. Fall-calving cows will need additional protein and energy to meet nutrient requirements. Cows less than three months postcalving will need 4.5 pounds per head per day of a supplement that is at least 30 percent protein and 90 percent TDN on a dry matter basis. Feeding 5 pounds per head per day of dried distillers grains would meet this need.
8. Weaned calves grazing cornstalks with a targeted gain of 1 pound per day will need to be fed an energy and protein supplement. Research has demonstrated that dried distillers grains fed at 2 pounds per head per day when calves are grazing cornstalks will usually meet this targeted gain.
9. Deep snow and ice can severely limit the ability of cattle to graze cornstalks. Have a backup plan and other feed resources available to meet cattle needs when this occurs.