Research Coordinator: Dr. Akim Omokanye
Collaborating Producer: Lawrence & Lori Andruchiw, Happy Valley (Saddle Hills County)
From: Peace Country Beef & Forage Association 2013 Annual Report
Corn is known as a forage crop that has the potential of yielding more energy per acre than any other forage crop in areas of western Canada, which have suitable heat units to get corn to the required half milk line stage for silage or grazing. Additionally, corn has an advantage as a winter grazing crop because it stands above the snow, and it stands up in windy conditions as well as providing a windbreak for cattle grazing it. Using live-stock to graze corn reduces the need for investing in harvest and feeding equipment. 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.
Methods
The trial was carried out at Double LA Farms (Lawrence & Lori Andruchiw) in the Happy Valley area, near Spirit River, Saddle Hills County. The site (27 acres) had corn varieties tested on it the year before and was grazed with 77 cows and 2 bulls.
On May 21, 2013, five corn varieties (39F44, 39M26, 2501RR, Fusion R, DKC26-28) with varied corn heat units were seeded with a 6-row corn planter. Fertility according to soil tests consisted of 84 N + 37 P + 0K + 8 S (actual nutrient lbs/acre). Roundup was used to control weeds @0.67 L/ac on June 25.
On October 7, forage yield was determined from harvesting four 17.5ft long corn rows per corn hybrid. Some corn plants were chopped with a wood chipper for determination of moisture content and feed value in a commercial 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
There was mostly one cob per plant for hybrids tested (Table 1).
At harvest, per cent DM varied greatly from 16.35% for 39F44 to 23.31% for 2501RR (Table 1).
At harvest on October 7, DKC26-28, 39F44 and 39M26 were mostly in the 2/3 milk line stage. Some of the Fusion RR and2501RR were in the half milk stage, but a lot of the cobs were observed a little bit far from the half milk stage.
Corn hybrid 39F44 had the highest DM yield( 5.09 ton/acre), followed by both 2501RR and 39M26 (4.70 ton/acre). Both Fusion RR and DKC 26-28 had <4.0 ton DM/ac (Table 1).
Corn forage protein was generally >9.0% for all corn hybrids (Table 1). 39F44 had the highest protein (12.98%). Protein content increased with decreased corn heat unit requirements of the corn hybrids tested. All corn hybrids tested in this trial were well above the protein requirements of 7-9% by a gestating cow in the mid and late pregnancy stages.
Forage Ca content varied from 0.24 for Fusion RR to 0.39% for DKC 26-28. P content varied from 0.16-0.20%. Mg and K respectively varied from 0.22-0.28% and 1.56-2.40%. All corn hybrids tested here had sufficient amounts of minerals (particularly Ca, P, Mg & K) needed by a dry gestating cow.
The energy (% TDN) content of tested hybrids was generally >60.0% (Table 1). This shows that the all corn hybrids were able to meet the needed energy by a cow in the mid pregnancy stage, which requires 55% and even when the cow is in the late pregnancy stage with more energy needs (60% TDN).
Conclusion
Looking at the DM yield and feed quality indicators measured in this trial, 39F44 appeared to have higher DM yield, protein and minerals (particularly Ca, P, Mg, K) than other corn hybrids. 39F44 has the lowest corn heat requirements (2000) than any corn hybrids and this probably explains why it has performed better than the other hybrids. As a reminder, 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. 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.
The entire field was grazed for 44 days with 35 cows and 7 calves.