To date, it’s been a dry, hot summer. Second cutting of grass meadows has been non-existent. Pasture is short or gone. Many farms have been feeding hay, hay which may be in short supply. What does this mean for the upcoming winter? As a farm manager you either need to reduce demand or increase supply. Reducing demand can be accomplished by weaning early. Feed efficiency is improved by feeding directly to calves as compared with cows. Also by weaning, nutrient requirements of the dam are greatly reduced. Additionally, this may be a good year to cull deeper into the cow herd to reduce overall stored feed requirements.
Numerous methods increase feed supply:
- Purchase hay
- Utilize vegetable processing waste
- Other byproducts (brewers grains, distillers grains)
- Plant winter annuals
- Supplement with grain
- Grazing corn residue
Each option has its application depending on local conditions and availability. The cost of increasing the feed supply with these alternatives may also be prohibitive.
In this column I will focus on use of corn residue, or what remains following the harvesting of corn for grain. Corn residue consists of grain, stalks, leaves, husks and cobs. Often referred to as corn stalks or stover, an acre of corn produces about one pound of residue for each pound of grain harvested. For example a 125 bu/acre yield would leave about 7,000 lbs. of residue per acre. Of this about 50 percent would be utilized by cattle.
Corn stalks can be an inexpensive feed source and are widely used in corn-producing regions of the U.S. In fact on a beef tour several years ago in Nebraska, a ranch that we visited walked their cowherd 10 miles to get to corn stalks.
Nutrient value: The average nutrient value of corn stalks and requirements are shown in Table 1.
Cattle are selective grazers, grazing the grain, husks and leaves first, which are the most palatable and nutritious. Additionally over the grazing season the quality of the residue will decline due to weathering. Therefore early in the grazing season, energy (total digestible nutrients) and protein requirements will be met; supplementation, especially with a protein source, may be necessary as the season progresses.
Length of grazing season: Depending on yield and cow size, one acre of stalks can support a cow for 30 to 60 days. During the first 30 days, no supplemental feed should be necessary. During the last 30 days consider protein supplementation – dried distillers grains or soybean meal. When grain is no longer seen in the manure, it’s a good indicator that supplementation should begin. A balanced mineral and vitamin should be offered free-choice.
Water: Providing water may be a limiting factor. A 1,400-lb. dry cow will drink about 10 gallons of water per day. If a source is not available in or near the crop field, then hauling is the only option, though inconvenient.
Fence: Most corn fields in the Northeast will not be fenced, therefore a temporary electric fence is the best option. This can be light gauge wire, electrified tape or braided twine. Twisted polywire is not recommended as it is less visible and deer are more likely to break it. Line posts can be the “step in” variety with heavier wood, steel or fiber/plastic/composite posts at corners and dips. If electric is not available, there are several brands of solar-powered fence chargers. Cows are quickly trained to electric; as long as there is enough to eat and drink they should not test the fence.
In Table 2, I’ve projected the cost of using temporary fence to enclose a 40-acre field, which has a perimeter of 1 mile (5,280 ft).
Actual cost will vary with local conditions, but the calculated cost per foot is a little less than 50 percent of the cost of material to build a permanent 4 wire high tensile fence. That said, I trust this estimate.
A 1,400-lb. cow will consume 30 pounds of hay per day. At $1.29 per day this equates to hay with a value of $86/ton. Remember that this is an initial cost for 1 year. These materials should have a useful lifespan of at least five up to 10 years.
Rental: If we farmed in Nebraska, there would be a going rate for rental of corn stalks, providing some basis for pricing; but as grazing corn stalks locally is not common, we have to develop our own pricing.
Fortunately, a tool from the University of Nebraska can help. Called the “Corn Stalk Grazing Calculator,” this Excel spreadsheet can be downloaded from http://extension.unl.edu/statewide/westcentral/ageconomics/.
Here’s the scenario. I have 25 cows weighing 1,400 lbs. A neighbor has a 40-acre corn field she would consider leasing. How many days of grazing will these 40 acres of corn stalks provide? The spreadsheet will need several inputs:
- Corn yield. This directly influences the amount of residue available. I used 125 bu/acre.
- Stalk harvest efficiency. The recommendation is 50 percent.
- Nutritive value of residue. I used the values in Table 1 of this article.
- Transportation and management trips to view the cattle. The cattle were close to the neighbor and the cost of freight and time to visit would be negligible.
Using the calculator it was determined that these 40 acres could support 25 cows for 45 days. Changes in corn yield and stalk harvest efficiency will affect the number of days grazing or the number of animals this land will support.
Now that we know the land is capable of supporting the cattle, what about the rental rate? Table 3 provides data to guide your decision.
Given this scenario, the value of the corn stalks is $24 to $61/ton at rental rates of $10 to $25/acre. What do you value a ton of hay? Or if you want to pay and a per-head, per-day basis the range would be 36 cents to 89 cents/hd/day for the same range in rental rates.
Other costs need to be covered, requiring negotiation between cattle owner and land owner. Who builds and maintains fences and watering systems? Who monitors the cattle? Who provides minerals and hay when winter weather prevents grazing? In the Northeast, generally the cattle owner will be responsible. Therefore these costs need to be considered and will affect the amount you can pay for the corn stalks.
Other considerations: Strip grazing should be considered. This evens out the nutritional quality because the cattle will be forced to consume the higher and lower quality components of the residue within a given grazing period before the fence is moved to provide a new strip.
When first put in the field, cows will naturally seek out corn grain. This can lead to acidosis, which, in the most severe cases, can cause death. Another concern, especially in drought years is nitrate poisoning. Nitrates accumulate in the base of the stalks and are not very palatable so cows should avoid them. In both cases, however, make sure the cows are full of hay before turning out. Feeding 5 lb/d of grain 5 days prior to turn out will transition the rumen to starch digesting microbes to protect them when consuming excess grain.
Nutrient removal: Not much work has been done in the Northeast evaluating the effect of removing corn residue on soil organic matter and fertility. According to work from Michigan State University Extension returning stover to the field increases short- and long-term soil carbon pools that help to build soil tilth, infiltration, water retention and nutrient availability. Yet returning 100 percent of the stover may not be necessary. “As a general rule of thumb, most soils in Michigan need about one-third of the corn stover returned to the soil each year to maintain soil organic matter. This leaves about two-thirds of the crop that could be harvested for livestock feed…” Contact your local Extension agronomist for more information.
Soil compaction: This varies by soil type and time of year. A 15-year study at the University of Nebraska has shown that fall grazing of corn stalks does not decrease yield in the following soybean or corn crop. Likewise, no-till research at Iowa State University found no significant difference in soybean yields between grazed and un-grazed corn stalks.
- Grazing corn stalks is comparable to feeding hay valued at $24 to $61/ton, which is much lower than the cost of production or market value.
- One acre can carry one cow for 30 to 60 days.
- Cows will selectively graze the more palatable portions of the plant first: (1) grain; (2) leaves and husks; (3) cobs and stalks.
- Expected production of residue is equal to the corn yield (125 bu = 125 x 56 = 7,000 lb. residue).
- Expected recovery of residue by grazing is about 25 percent to 50 percent.
- Strip grazing increases yield recovery.
- For first 30 days, a balanced complete mineral supplement is adequate.
- After 30 days, supplemental protein and energy should be considered.
- Over-feeding of supplemental energy will discourage cows from grazing.