Corn for Silage Grazing & Silage Production

Research Coordinator: Dr. Akim Omokanye

Collaborating Producer: Pat & Jay Eaton, Valleyview (MD of Greenview)

From: Peace Country Beef & Forage Association 2013 Annual Report

Corn, being a warm-season annual grass, can be planted in parts of the Peace for corn silage or grazing. As an annual, it can be grazed successfully during the fall and winter to extend the grazing season, and thereby reducing feed cost per head per day. This is because using livestock to graze corn reduces the need for investing in harvest and feeding equipment. Sam King, a producer with years of experience grazing standing corn in the region averages 55 cents/cow/day at a yield of seven to eight tons DM/acre, while his brome aftermath feed costs him $1/cow/day. With the potential to produce more than 10 tons of forage dry matter to the acre, few annual crops can compare to corn in terms of dry-matter (DM) yield per acre and cost per pound of gain. Depending on the type of livestock used, producers may have to supplement to compensate for lower protein levels. The following report looks at corn production on 155 acres for grazing and silage.


There were three corn fields and all fields were near Valleyview at Pat and Jay Eaton’s ranch. One field was on Alder Ridge Road by RGE road 204 (50 acres, field 1). The other two fields were on RGE road 205 (35 acres (field 2) & 70 acres (field 3). Fields 1 & 2 had corn last year. The new addition this year was field 3.

Two corn varieties (BrettYoung corn Fusion RR and Pioneer corn 39F44) were seeded. Fusion RR has a corn heat unit requirement (CHU) of 2350, while 39F44 requires 2000 heat units to get to full grain maturity. The CHUs rating is an indicator of how many heat units are required for the grain to reach maturity. On average, 200 fewer CHUs are required for grazing or silage corn to reach 65 per cent whole plant moisture (35 per cent dry matter) as compared to grain corn. This moisture level is normally when silage corn is ready to harvest. Fields 1 & 2 were seeded on May 16, and field 3 was seeded on May 15. Seeding was done with an Air Seeder at 12-inch row spacing.

Fertility was 150 lbs/acre blend consisting of 75% 46-0-0 + 25% 11-51-0 (field 1), 65 lbs/acre blend consisting of 75% 46-0-0 + 25% 11-51-0 (field 2) & 250 lbs/acre blend consisting of 75% 46-0-0 + 25% 11-51-0 (field 3).

Weeds were controlled once with Roundup at 0.67 L/acre.

On October 7, corn forage yield for each field was determined. Some corn plants were chopped with a small wood chipper for determination of moisture content and feed value in a commercial laboratory. On the sampling day, the number of cobs per plant, plant population and cob maturity were determined. Field 3 corn was ensiled at about two-third milk line stage (with about 70% moisture) using a corn silage chopper.

Results and Discussion

Cobs per Plant, Cob Maturity and Forage Yield

The number of cobs per plant was in the order of: 1.93 for Fusion RR (field 1) > 1.53 for Fusion + 39F44 (field 2) > 1.20 for 39F44 (field 3) (Table 1).

At harvest for forage yield estimation (wet & DM) on October 7, the cobs corn hybrids fields 1 and 2 had 1/4 to 1/2 milk line stage. For field 3, which had 39F44, the cobs had between 1/2 and 2/3 milk line.

The percent DM (about 30%) at harvest was similar for the corn hybrids used at different fields (Table 1).

Wet forage yield was highest for Fusion RR (25.9 ton/acre) in field 1, closely followed by field 2 that had Fusion RR + 39F44 (24.6 ton/acre) and then 39F44 with 17.0 ton/acre (field 3).

Forage DM yield followed the same trend with wet yield. The DM yields were 7.53, 7.30 and 5.10 ton/acre respectively for fields 1, 2 and 3. To increase the chances of a high yielding and high quality corn crop for grazing, it is advisable to select a variety that will match the CHUs rating for your area. Select an early-maturing silage corn variety. Silage varieties of corn are more palatable and better suited to grazing than grain corn.

Field 3 had more plant population than other fields, indicative that seeding was done at a higher rate. This probably explains why field 3 had more than 2 tons/DM/acre than fields 1 and 2. Corn does not like competition, even with itself, so adequate seeding rate and appropriate spacing between corn stands is essential.

Forage Quality

Forage protein was higher for field 1 (10.1%), followed by field 3 (9.47%) and then field 2 (8.13%). The protein requirements for a dry gestating cow in the mid pregnancy stage was conveniently met by the corn on all fields. For a cow that is in the late pregnancy stage, only field 2 corn fell short of 9% protein, which is needed by this category of cow. Grazing cows in the late pregnancy stage on field 2 would therefore require some form of protein supplementation in the form of a good legume hay or protein blocks.

Fusion RR (field 1) had the highest Ca, Mg and K contents than other fields. But the requirements of Ca, P, Mg and K by a dry gestating cow in the mid and late pregnancy stages were all met and even exceed-ed by corn on all fields.

Corn hybrids in field 3 (39F44) had the highest energy content (63.6% TDN) than other fields. The high energy content in field 3 resulted from the advanced stage of cobs at harvest, which were mostly around the 2/3 milk line stage. Generally, the TDN values obtained for the 3 fields were within the range of 55-60% TDN suggested for dry gestating cows.

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