Stocking rate on corn residue is extremely important because it affects the animal’s plane of nutrition. When grazing corn residue, cattle select dropped corn grain along with the husks and leaves. Digestibility or energy available from the diet is quite high at the initiation of grazing, but declines with time because cattle select the more digestible parts such as grain and husk early in the grazing period. The corn grain itself has more energy (83% TDN) and protein (9% CP) than any other plant part. Husk is about 60% TDN and leaf is about 50% TDN. Cattle consume cob and upper stalk (which are low energy; 35% TDN) only when availability of husk and leaf is limiting.
This information has been the basis of stocking rate recommendations (remember other losses will occur such as wind and trampling loss). The general rule of thumb is that corn residue can be stocked at 1 cow (1200 lb) for one month for every 100 bu of corn (Table 1). At this stocking rate, cattle would be consuming 50% of the leaf and husk available which is only 15% of the total corn residue produced.
| Corn Yield, bu/ac | Animal Unit Month1 (AUM)/ac | # of grazing days at one 1200 lb cow/ac |
| 100 | 1.1 | 28 |
| 125 | 1.4 | 36 |
| 150 | 1.7 | 43 |
| 175 | 2 | 50 |
| 200 | 2.3 | 57 |
| 225 | 2.6 | 64 |
| 250 | 2.8 | 71 |
| 1One Animal Unit Month (AUM) is the amount of forage required to sustain a 1,000 pound cow or equivalent for one month | ||
Stocking density can be used to influence an animal’s plane of nutrition. Some producers use a higher stocking density and a shorter amount of time and move cows from field to field over the winter. With this type of grazing, the plane of nutrition cycles with nutrition being greatest at the start of a new field and then declining until they start in a new field again. This allows producers to provide a more nutrient-dense diet in late winter when spring calving cow’s requirements are greater. Although there is a nutritional benefit to this strategy, there is also the risk of winter weather such as ice restricting grazing such that the cattle must be removed from residue grazing, resulting in some fields not being grazed and thus the highest quality components in those fields not being used.
Do you want to calculate how long you can graze, given the yield, acres, and number of cows you have? Then check out the Excel based Corn Stalk Grazing Calculator. It can also be used to calculate the cost when accounting for rental rates, hauling of cattle, and other labor.
For more on this topic, explore the related YouTube video: Grazing Corn Residue with Cattle: common nutrition questions answered.