Forage Yield & Feed Quality of Four Corn Hybrids

Research Coordinator: Dr. Akim Omokanye

Collaborating Producers: Peter & Marilyn Dolen, Fourth Creek (Saddle Hills County)

From: Peace Country Beef & Forage Association 2013 Annual Report

Corn is an option for producers looking to extend the grazing season and reduce feed costs per cow per day. Corn is a high energy feed with protein levels that will normally match the nutritional needs of a dry cow in mid and late pregnancy. It also has the potential to produce more dry matter than tame hay or forage cereals. By replacing other forms of feed with standing corn particularly in late fall and during winter, labour time, machinery use and associated costs are reduced as no summer feed harvesting is required and winter supple-mental feeding is limited. Through a series of corn field days and on-farm trials and demonstrations, and the support of seed companies in the Peace, PCBFA continues to renew producer’s interest and awareness in using corn to extend the grazing season. PCBFA works with producers in many parts of the Peace to help them evaluate corn hybrids and identify suitable hybrids for extending the grazing season of beef cows for their area. The following report is one of these mentioned collaborations.

Methods

The trial took place at Peter & Marilyn Dolen’s farm (RGE RD 81) in Fourth Creek (Saddle Hills County) on a 50 acre field. The site has had corn hybrids tested twice before the present trial. In 2012, corn grazing lasted for 32 days. Soil test done before seeding showed excess amounts of N needed for a corn crop for the year, so no dry N fertilizer was applied. Liquid fertilizer consisting of the following nutrients was applied: Alpine (6-22-2), copper, boron, manganese, zinc and magnesium. Seeding was done on May 20 with a 6-row corn planter at 30-inch row spacing. Four corn hybrids were seeded (Pioneer corn P7443R, Pioneer corn P7213R, Monsanto corn DKC 26-25 and Pioneer corn 39F44). Weeds were controlled with Roundup.

On October 7, forage yield was determined from harvesting four 17.5ft long corn rows per corn hybrid. The corn forage samples were weighed fresh. Some corn plants were chopped with a wood chipper for determination of moisture content and feed value in a laboratory. Dry matter (DM) yield was later calculated for each corn hybrid. On the sampling day, the numbers of cobs per plant, cob maturity and final stand count were also determined.

Results and Discussion

Number of Cobs, Cob Maturity, % DM, Plant Population and DM Yield (Table 1)

One cob per plant was recorded for each corn hybrid.

Percent DM at harvest varied from 17.76% for P7213R to 24.48% for P7443R.

The cobs were at the half milk line stage for P7213R, P7443R and DKC 26-25 and about 2/3 milk line stage for 39F44.

Final plant population at harvest was more than 36,000 plants per acre for each corn hybrid.

Pioneer corn 39F44 had the most DM yield (5.97 ton/acre). Next was Pioneer corn P7443R with 5.28 ton/acre. Both Pioneer corn P7213R & Monsanto DKC 26-25 had less than 5 ton/acre.

Forage Quality (Table 1)

Protein was highest for Pioneer corn 39F44 (10.66%) and lowest for Pioneer corn P7443R (8.61%). The protein level obtained for all corn was adequate for a dry gestating cow in the mid and late pregnancy stages.

Forage Ca & P contents was highest for Pioneer 39F44. Generally, all corn hybrids were able to meet 0.18% Ca requirement by a dry gestating cow from mid to late pregnancy stage. But of the 4 corn hybrids tested here, only one (P7213R) fell short of P needed by a dry gestating cow. Corn forage Mg content was similar for all hybrids tested here. But K content varied greatly among hybrids. The amounts of 0.12 % Mg and 0.6% K suggested for a dry gestating cows were far exceeded by all corn hybrids.

Energy (TDN) varied from 57.9% for P7213R to 61.0 for DKC26-25. Energy was >60% for 2 of the 4 hybrids.

Notes on Savings on Fertilizer Application

As pre-seeding soil tests indicated sufficient N in the soil for corn growth for the year, no dry N fertilizer was applied during and after seeding. Small amount of N was however present in the liquid fertilizer applied, which mainly consisted of P, Cu, B, Mn, Mg and Zn. The lack of additional N fertilizer application in 2013 resulted in fertilizer savings of $76.48 per acre compared to 2012 season. This benefit came as a result of subsequent corn grazings for some years now at the site.

Conclusion

In general, Pioneer corn 39F44 with 2000 heat units appeared to have slightly higher DM yield, protein and minerals (particularly Ca & P) than other corn hybrids. Because cows selectively graze cobs first, it is important to control access to the corn to ensure proper utilization, and to provide a good water source and mineral/salt package to address any short falls. The reduction in direct input costs for 2013, should further reduce feeding cost/head/day.