We are blessed in the Midway District to be well diversified with some of the best grazing country around and highly productive farm ground. A great portion of this farm ground is planted to corn and grain sorghum yearly. When the grass dries up, crop residues are an excellent option for a feed source. With the high grain prices in the past years, we saw pasture ground being converted to farm ground to generate more revenue off of the land. Now the tables have turned with low grain prices and record high cattle prices. Why not graze the residues and increase the profit coming off of these farm acres?
What is nutritive value of crop residues?
While some have concerns from the agronomic side about grazing crop residues, there are many great benefits to consider. As long as cattle have grain and leaves to select from, corn and grain sorghum residue is comparable in nutritional value to grass hay (52-56 TDN Total Digestible Nutrients) and around 7 percent protein. Excess grain is usually the first to be consumed in fields followed by the leaf for milo fields, and the leaf and husk for corn fields. The stalk is lowest in protein and palatability leaving good reason for cattle to be removed before they are forced to eat the stalk. It is important to note that as the residues deteriorate over time, so does the nutritional value, thus supplementation may be needed through the winter months. Once the grain has been utilized by the cows, proper protein supplementation should be provided. The leaves and husks, on average, provide about 5.5 percent crude protein which is deficient for a mid to late gestation cow.
What should I be aware of when grazing crop residues?
Along with the benefits of grazing crop residues, comes some risk that producers should be aware of. As many of you already know, nitrates can develop and accumulate in corn and sorghum during, or after periods of stress. Prussic acid can develop in sorghum plants, but will usually disappear around ten days after the first hard freeze. Nitrates develop in the lower portions of the stalk, compared to prussic acid which develops in the leaves of the plant. If you suspect either of these to be present in your field I recommend sending in a sample of each to be tested. We are able to assist you with both of those tests at the extension office.
Another concern for grazing residues is too much grain left in the field for grazing. Because of the hard outer coat, the grain in a sorghum stubble field is not well digested by cattle, yet when there are large amounts of grain available, founder can occur. One grain sorghum head has about 0.12 lbs of grain, and about 466 sorghum heads would equal 1 bushel of sorghum (1 bushel = 56 pounds). Caution should be taken when fields approach 10 bushels left in the field to avoid founder. Too much intake of corn in a short period of time can cause acidosis. Caution should be taken when excess of 8-12 bushels per acre of corn, is left in the field.
Crop residues are a cost effective way, to maintain and or improve the body condition of your cowherd before calving season. Harvested feed represents the largest cost associated with a cowherd. Whenever the grazing season can be extended, you should experience cost savings. Even though there can be some intensive labor involved, with fencing, hauling water, and transporting the cattle, the nutritional benefits and cost savings make the hard work worth it.
For more information livestock and forage topics contact the Midway District Extension office or call (785)483-3157 or (785)472-4442. Dusti Lynne Cason serves as the Midway Extension District Livestock Production Agent. All Kansas Extension education programs and materials are available to all individuals without discrimination on the basis of race, color, national origin, sex, age, or handicap.