Dry Pregnant Cows
When spring calving herds are grazing corn residue, cows are only in their second trimester of pregnancy and have their lowest nutrient requirements if they are in a good body condition (BCS of 5 to 6). A mature cow can maintain her weight consuming 26 pounds of residue (dry matter basis). If the cows need to gain body condition, a supplement will need to be provided. Dry pregnant cows require little to no protein or energy supplementation until late in gestation. While supplementation is not needed, it is still important to provide cows with a free-choice mineral targeting intake of 4 ounces per day. This amount changes based on your mineral. Check your mineral feed tag for recommended intake level. Consult with your nutritionist or extension specialists to determine the best mineral for your area.
Weather plays a big factor in how long our cows can graze corn residue. Most cows can graze fields that have up to 4 to 6 inches of snow cover. However, cattle are not able to graze fields that are covered in ice. Therefore, the length of grazing time is variable and dependent on weather conditions.
Subsequent Crop Concern
It is not uncommon to hear concerns about grazing corn residue affecting the soil and subsequent crop productivity. Soil compaction is commonly talked about, as compaction can subsequently reduce crop yield. However, several studies conducted by the University of Nebraska-Lincoln found that grazing in the late fall or winter did not result in significant compaction on cropland or negative impacts on crop yields. The specific fields in the studies were managed under a no-till land management strategy and in a corn-soybean rotation. Fall grazing of corn residue improved soybean yields by 3.4 bushels per-acre. Grazing fields managed under continuous corn had no impact on subsequent crop yield, 239 bushels per-acre grazed versus 223 bushels per-acre ungrazed. It is also important to remember that most of the nutrients (including Nitrogen, Phosphorus, Potassium, and Calcium) consumed by the cattle are excreted back on the land.
Compaction is a main concern for crop producers, and minor surface compaction can result from grazing during wet weather. This compaction disappears through natural wetting, drying, freezing, and thawing processes. Compaction levels for restricting root growth do not carry over into following growing seasons.
Conclusion
Corn residue grazing can benefit both cattle and crop producers. Corn residue is an economical feed source for cattle over the winter months and can provide an extra source of income for crop producers without detrimental effects to the land.
Source : sdsu.edu