Grazing calves on corn residue and providing supplemental distillers grains is a cost effective way to add value to weaned calves. The two most important considerations to successfully and economically increase calf value are stocking rate and supplementation level.
Grazing corn residue is unique from other forages in that the total amount of forage available is present at turn out. Because the quality and availability of forage decreases over time, following the recommended stocking rate is essential to achieving targeted gains.
It is important to remember that for every bushel of corn produced, there are approximately 16 pounds of leaf and husk. However, some leaf and husk will be lost to wind and trampling. Based on this, the recommend stocking rates are based on the availability of 8 pounds of leaf and husk per bushel of corn. This means that fields with greater grain production can have greater stocking rates than fields with lower grain yields (Table 1).
Data from UNL research suggests that supplemented 600-lb calves grazing irrigated corn fields with 3 lbs/d (as-fed) of dry distillers grains (DDGS) will gain 1.3 lbs/d. When the supplementation level is increased to 6 lbs/d (as-fed) of DDGS gains increase to 1.8 lbs/d. Using a price of $150/ton for DDGS, it will cost $0.23 per day for the supplement at 3 lbs/d and $0.45 per day at 6 lbs/d.
If you are close to an ethanol plant, modified distillers grains (MDGS) are usually a less expensive source of protein and energy than dried distillers grains. It is important to remember that modified distillers are about 50% DM, so twice the amount is required to achieve the same gain as supplementing dried distillers grains (Table 2).