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What’s all the fuss about corn on the Prairies?

What’s the potential for silage and grain corn in Western Canada? That’s the question federal researchers Vern Baron in Lacombe and Karen Beauchemin in Lethbridge are trying to answer with the financial backing of Agriculture and Agri-Food Canada and the Beef Cattle Research Council’s Beef Research Cluster.

“It is estimated that there is a potential to grow two million acres plus of corn in the western provinces,” says Baron. There have been increased breeding efforts by the major corn-breeding companies. They have massive funding available to develop new corn technologies, and we now have earlier lines and Roundup-resistant corn varieties.

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“The difference in producing corn silage in the environment of the prairie of Western Canada than in southern Ontario and the U.S. Corn Belt is we have a shorter growing season. Now we have short-season corn varieties that require 2000 heat units which equals maturity in 52 days using the Minnesota heat unit system. In that system a 2600 corn heat unit variety is equal to maturing in 78 days. We have several different varieties of early-season corn to choose from but we still have late frost in the spring and early frost in the fall.”

Corn heat unit zones are mapped according to the growing season beginning on the first date in spring after three consecutive days with the mean daily temperature of 10 C and ending on the date of the average occurrence of -2 C in the fall.

“The main objective of this research is to explore greater use of forages in beef cattle production, while maintaining animal performance and carcass quality. We want to develop new information to allow the beef cattle industry to decrease its reliance on grain, and make greater use of high-energy forages such as corn silage,” adds Beauchemin.

“We want to establish relationships among yield, physiological maturity and nutrient content of short/mid-season hybrids and develop a means of predicting energy content of short/mid-season corn silage hybrids.”

In Western Canada barley is still the major silage crop. In 2011, in Alberta, barley for grain was grown on 3.7 million acres, nearly half a million acres for silage or greenfeed.

Barley needs cool, moist weather — 20 to 21 C is best for growing barley while corn needs hot weather and likes 30 C temperatures. On average, Baron says Lacombe, Alta., sees five days above 30 C during a growing season yet the corn must be done silking by the end of July in order to fill sufficiently for silage by the first frost.

“Barley silage can be planted at several dates and mature within the growing season. However, there is less flexibility for corn hybrids in short-season areas. Shorter-season hybrids can be grown in longer-season areas but it is risky to plant longer-season hybrids in short-season adaptation zones as a means of increasing yield,” says Baron. “Here at Lacombe we have average corn heat units (CHU) of 1850. Our silage yield was 7.8, 15.4 and 17.7 tonnes per hectare (4.37, 6.8, 7.9 tons/acre) in years when the CHU from planting to harvest were 1650, 1950 and 2250 respectively. In regions well adapted for corn, the grain fills rapidly and linearly over a three- to four-week period. Beginning about 14 days after silking, the corn kernel and plant can accumulate at about three to four per cent of maximum yield per day. However, in short-season areas where frost can occur prior to or during the growing season, when the silage is between 25-30 per cent dry matter, grain filling will be limited. This will result in the starch or energy content being low and the kernel moisture above 50 per cent.

“As long as growth is not interrupted by frost, later-maturing corn hybrids have higher silage yield than adapted ones within a maturity zone. The strategy is to use the whole arable season for corn growth. Hybrids growing at the same rate will yield more in the longer-season regions. Since the time of grain maturity occurs after the time of maximum silage yield a later hybrid can be chosen for silage than for grain. Thus hybrids used for silage can have grain maturity ratings 100 to 200 CHU later that that required for grain. As the corn heat units increase with later varieties of corn you will see higher yields,” he says.

They planted corn at Vauxhall, Lethbridge, Lacombe, Elm Creek, Man. and Ottawa in 30-inch rows at 35,000 plants per acre. Silage yields averaged 6.8 tons/acre across all plots; 6.6 tons/acre at Lacombe and 7.3 at Lethbridge. In each location earlier varieties were lower yielding than the average while later varieties yielded higher than the average.

Grain corn yields increased over the years with the introduction of better varieties. In 2013, Alberta Corn Committee trials reported an average of 148 bushels per acre (bu./ac.) at Bow Island, Alta.,  and 160 bu./ac. for the best variety. In Manitoba the record yield in 2014 was 226 bu./ac., but the provincial average over the last five years is 97 bu./ac. These are very respectable yields for Western Canada. By comparison the average yield in the U.S. Corn Belt is 160 bu./ac. and the record is 350 bu./ac.

What’s all the rush about growing corn in Western Canada?  Is there a cost benefit?  Baron says it all depends on the harvest quality of your corn and where and how you will market it. Depending on where you live you may be able to sell grain corn to distillers but this depends on the quality. You can feed it or sell it as high-moisture grain or silage for beef or dairy rations or winter grazing cows.

Approximately 50 per cent of the dairy farmers in Alberta have tried or switched to corn for silage, some because they are continually having disease and lodging issues with barley for silage. Corn doesn’t lodge. With high grain prices they are finding the higher silage yields from corn offers an advantage to their operation.

Corn costs about 1.5 times more than barley for silage and the harvest occurs at distinctly different times of the year, August for barley versus late September or early October for corn. Both have to be ensiled at silage dry matter between 30 to 40 per cent. Freezing corn to achieve the ideal dry matter percentage for ensiling may result in overdrying the silage resulting in hard, dry kernels which require further processing for efficient digestion by cattle.

Beauchemin is evaluating the increased use of high-energy corn in feedlot rations. Both she and Baron are looking at the increase in fibre digestibility, and starch or energy content in corn along with the increased yields as compared to traditional barley-based rations.

At Lacombe they are able to get 20 per cent starch with corn, compared to 30 per cent starch in the U.S. due to the immaturity of the Lacombe corn. On the other hand, a starch yield of 20 per cent in barley is unusually high.

Corn silage that is processed with additional processing of the kernels is highly digestible (+92 per cent). An increase in the starch content of the silage with maturity has a positive impact on the energy content of the feed. As starch content in the kernels increases the digestibility of the remaining plant material decreases, but the overall energy content of the corn silage increases as long as the corn is processed.

“In barley, it is difficult to attain the high starch content that we see in corn with high dry matter yields,” notes Baron. “However, the starch concentration in barley could be similar or greater than immature corn silage. To maximize intake and digestibility we recommend that corn silage be harvested between 35-40 per cent with no frost.

Baron has been evaluating corn for winter grazing beef cows for a number of years. He has looked at the cost-benefit analysis of standing corn versus swathing the crop and the potential problems of grazing corn, especially potential grain overload.

Total daily feeding cost averaged over several years were $ 0.78 per cow per day for swath grazing triticale, $1.05 for grazing corn, $1.24 for swath grazing barley and $1.98 for a traditional total mixed ration of silage, straw and limited grain. A full report can be found at foragebeef.ca.

About the author

Contributor

Duane McCartney is a retired forage-beef systems research scientist at Lacombe, Alta.

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