Several options exist to provide quality grazing during seasons when many common forages have gone dormant or are less productive. Non-traditional forages can provide high quality grazing throughout the hot summer months and into the fall. Corn is mainly used in Kentucky for grain or silage. Grazing green corn can be a valuable method to extend the grazing season and reduce stored feed needs without the expenses of harvesting and feeding equipment. Many Kentucky producers have grazed corn as a stockpiled forage with mature ears overwinter, but the focus of this article is grazing corn during the vegetative or leafy stage.

The nutrients needed to produce a high yielding corn crop for grain are higher than most other forages used for grazing. The nitrogen requirements for corn generally range from 125-150 lbs. of nitrogen per acre. If planting with the intention of grazing before grain development, the fertilizer requirements can be lowered to similar recommendations of other warm season annual grasses that produce 3-5 tons dry matter. Soil tests need to be taken to determine the phosphorous and potassium needs for the specific location.

Grazing corn in an early vegetative stage can provide a forage high in protein and digestible fiber. A demonstration conducted at the University of Wisconsin found that plants at a V9 stage (stalk with only 9 leaves) contained 18% crude protein and ADF of 36.6%. As the plant matures and begins to develop an ear, the percentage of protein will decrease to 12-15% at tasseling and around 8% once the plant reaches maturity. The fiber content in the plant will also increase as the plant matures and begins to produce an ear because a significant amount of the plant is stalk at this point. However, the total digestible nutrients (TDN) increase once the plant sets grain and reaches the milk/dough stage because of the weight and high energy content of the grain. So the question presented is, why would we want to graze corn before it fully matures?

The time frame to graze green corn is going to vary with growing degree days, date planted, and variety. A basic rule of thumb would be to plant by mid to late May, but corn can be planted later in the season if you want grazing for late summer. The number of days it takes to reach the tasseling stage is about 60 to 75 days depending on the variety used and weather conditions. If planted mid to late May, corn should be tasseling in mid to late July, when cool-season grasses are struggling with “summer slump.” Grazing corn during this time will allow a producer to remove cattle from cool-season pastures and let them rest and regrow until temperatures are cooler and growing conditions are more favorable.

Grazing corn while green may not provide the yield as mature corn, but it can still provide 4 to 6 tons of dry matter per acre. The Wisconsin research that produced this tonnage is based on using 30” rows and a 33,600 seeding population. The corn yield produced in 75 days is as much or more than a tall fescue stand will produce in an entire year. In 2014, a demonstration at the University of Kentucky Princeton station used 15” rows and a 60,000 seeding rate. The green corn was grazed with growing beef heifers. The average daily gain (ADG) was 2.2 pounds per day from July 7 until September 22. According to other research, if these animals had been grazing infected tall fescue during this time frame, the ADG would have been 1 pound or less per day.

Grazing green corn can be achieved during a time of the grazing season when other forages are not very productive, and need a rest period. The yield of green corn is less than mature corn, but is still impressive considering the short number of growing days it takes to reach tasseling. Another consideration when using corn is the opportunity it gives a producer to prepare a tall fescue based pasture for stockpiling for use later in the winter months.

Using best management practices with any forage is important to maximize utilization and reduce waste. Strip grazing will maximize utilization and make the diet more uniform as animals will be forced to graze both high and low quality parts of the plant rather than selectively grazing. This is especially important to aid in the prevention of acidosis or foundering. Trials have shown that providing 2 to 3 days of forage at a time is best. The area needed will vary depending on animal size, animal needs, and available forage. Temporary fencing is usually run through corn rows after driving down rows with an ATV and running poly wire or poly tape, supported by temporary fence posts, through this area in the field. When setting up the fence, provide enough space between corn and the fence to eliminate the wind blowing corn down or cows from placing partially eaten plants on the fence causing it to short out. Many producers allow livestock access to other stockpiled species, such as tall fescue, as a supplement to graze corn. Access to a grass field is also important as it provides a bedding place, and a holding area during wet conditions.

A few precautions exist when grazing corn. First, depending on animal requirements, the corn plant may not supply sufficient protein as the plant matures and it may be necessary to supplement protein using soybean meal, dried distillers grains or other plant protein sources. Next, nitrate poisoning can be a risk when grazing drought-stressed corn. Always test corn plants when high nitrate levels are suspected. In rare cases, founder has occurred in animals turned onto corn.

Although green corn is not a traditional grazing crop, it can provide quality feed in times of the year when other common forages are deficient or dormant. This warm-season grass is actively growing while cool-season grasses have slowed or become dormant during the summer months.

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Summer
Extending the Grazing Season