Corn grazing needs the right variety

Hybrid corn varieties designed for grazing are bred to grow the biggest plants and cobs rather than just the biggest cobs. | File photo

A seed company says 90 to 95 percent of corn hybrids are bred to be combined rather than used as silage or grazing

Is your corn bred for the herd or the combine?

That’s the question Tyler Russell of NorthStar Genetics asked during Ag in Motion’s Livestock Days, held at the Discovery Farm site near Langham, Sask., Aug. 20-21.

“We find there’s a lot of corn bred for a combine or for a grain versus corn bred for cows. Probably 90 to 95 percent of the hybrids out there are bred for grain,” said the company’s western Canadian manager.

Many livestock producers are familiar with ideal crop characteristics for grain corn like a short and stiff stalk, hard kernel, high ear height and fast dry down.

However, the traits breeders look for when selecting for silage and grazing-specific hybrids are considerably different.

“We want the whole plant, the kernel and as much tonnage as we can get. We want that plant to dry down slowly so we can chop it at the right time. We don’t want a really hard, dry kernel. We want something that’s soft and digestible by the cow so that they can get the most energy out of it,” said Russell.

“We are breeding directly for the cows so that they can perform at their best and that ranchers can get the most economical returns.”

NorthStar Genetics looks for 10 different traits when breeding a silage or grazing hybrid, including kernel starch digestibility that is important for cattle’s beef and milk production.

A wide chopping window is beneficial for the silage or grazing rancher to maximize nutrition and tonnage.

It’s also important to consider kernel moisture. Higher moisture is more digestible.

“Silage guys want that silage moisture to be around 60 to 68 percent moisture because it packs the best in the bunker, ferments the best,” Russell said.

Grain corn varieties typically have hard kernels to prevent breakage. However, cows don’t have the chewing power to break them down. It also takes more power for the chopper to break hard kernels.

“At the end of the day, it still breaks it into hard chunks, which are not as digestible in the rumen. So, the softer the kernel, the more it’s able to break, the better it is for a cow,” he said.

Hybrid grain corn is all about the best kernels and biggest cob rather than the size of the plant, “whereas with grazing and silage, I want as much tons as I can. Granted, 50 percent of the tonnage is in that cob, but the other 50 percent is in the leaf, the stalk and in the height of the plant,” said Russell.

The white cob of silage-specific hybrid corn varieties is more digestible for cows. | NorthStar Genetics photo

“We’re breeding it for the biggest plants and cobs, not just the biggest cob.”

Silage and grazing-specific hybrids also have the benefit of floury starch in their kernels.

“If it’s floury and can break up into really small pieces, it doesn’t have hard chunks. It’s going to have better rumen retention, which means that the cow is able to digest more energy and more leaf material from that starch,” he said.

Red cobs from a grain corn hybrid are designed to dry down quickly and drop their kernels, whereas silage and grazing-specific hybrids often have white cobs that are softer and hold kernels better.

Russell said cows prefer the latter.

“In grazing environments when a cow is eating the cob, if it’s red they spit it out. But they also spit out a lot of kernels because they didn’t like it and then you get waste droppage onto the ground.”

That becomes evident in the manure.

“Look at all the kernels that ended up in that manure. That means all that energy, over 50 percent of the corn plant energy, is packed in those kernels. And when you see those kernels flow right through the cow, that means they’re not putting up any of that energy,” he said.

Floury kernels that have been dried down to determine moisture still break up easily to create a large surface area for rumen retention. | NorthStar Genetics photo

Silage and grazing corn varieties have a longer dry-down window, even after frost.

“When they’re soft and breakable it doesn’t matter even when they’re maybe 30 days over ripe. They’re still breakable, soft, and get digested.”

Russell said corn performed well compared to other feed options during this year’s drought.

Against green feed, hay or barley silage, corn put up more tonnes per prospective pound, “and in many cases corn saved the herd.”

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