Is short season corn short on nutrients?

Researchers assess new corn silage varieties grown in different locations for protein content and digestibility and compare them to barley

Short season corn acres are increasing on the Prairies, and researchers want to know how the newer varieties work in feedlot rations.

Plenty of research on longer season corn varieties is available, but that doesn’t mean that the information about forage quality, harvest dates and yield will transfer to the newer shorter season varieties, said Reynold Bergen, science director with the Beef Cattle Research Council.

“The driving motivator for this research is the increased interest in short season hybrids. These things are going to become available, so let’s figure out how they may or may not work in cattle feed,” said Bergen, whose agency is funding federal research scientists Vern Baron at Lacombe and Karen Beauchemin at Lethbridge in the project.

“With these newer varieties, that will be useful in more places, there is value in figuring out how well they work in different areas. The concern that drove the research was the stage of maturity at which you harvest this stuff affects how well the silage turns out.”

About 500,000 acres of corn were grown for silage or greenfeed in Alberta in 2011, and it’s estimated there is the potential for more than two million acres of corn on the Prairies.

It’s also hoped the new research will provide needed information about the economic potential of incorporating corn silage into feedlot rations. Barley is the basis for most traditional prairie feedlot silage.

Bergen said comparing the longer and shorter season corn varieties is like comparing a Charolais and Angus in the feedlot.

“They are going to feed differently because they are going to mature differently. If you are going to switch from one to the other, you better have some sense of how those animals respond differently to different feeding programs,” said Bergen.

“If you got new varieties that are maturing earlier, the rate they mature will be different, therefore the rate at which they deposit starch in the cob, or the rate the plant starts to lignify, that will vary from variety to variety and vary depending on the growing season and vary from location to location.

“You can’t assume that just be-cause you have really, really good data on how to grow and harvest and feed a crop based on data collected on a long season variety in Lethbridge, grown under irrigation, that doesn’t mean it will grow the same in Lacombe or Manitoba, where you’ve got a different growing season, different elevation and different rainfall.”

Researchers will look at growing corn in Lethbridge, Vauxhall, Alta., Lacombe, Alta., Elk River, Man., and Ottawa.

They will grow six hybrids at each of the sites: two will be ideally suited for the location, two will require 200 fewer heat units and the other two will require 200 heat units more than the optimum for the location.

Bergen said the researchers will look at the optimal stage to harvest the newer corn silage varieties.

Traditionally, corn is harvested at 32 percent dry matter. Waiting longer increases energy but reduces digestibility. Harvesting earlier reduces silage quality but increases digestibility.

“It is a trade off.”

All the samples will be evaluated for chemical analysis, nutrient composition, digestibility and protein content. They will also be analyzed with a near infrared spectroscopy to get base line readings for future testing.

The NIR analysis is a quicker and cheaper way to evaluate nutrient content.

The Lethbridge site will also assess the silage in feeding trials compared to the traditional barley silage ration.

Contact mary.macarthur@producer.com

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