If cornstalks are the main winter feed for your beef cows, but the animals don’t seem to do as well on them as they did 20 years ago, there may be valid reasons, says Bruce Anderson, University of Nebraska Extension forage agronomist.

First, he says cows are bigger today, so they need more forage and usually greater supplementation.

“So a quarter-section of stalks won’t carry as many cows as it once did,” says Anderson. “And even when stocking adjustments are made, if supplements aren’t also adjusted accordingly, cow performance still might suffer.”

It’s also likely that stalk fields have changed, he says. For one thing, modern combines collect grain more effectively, leaving half as much in fields.

“Less grain means we need to supplement cows earlier than before. Otherwise we risk them going out of condition as well as lowering eventual production capacity of their calves.”

The stalks themselves also might be less nutritious. Modern hybrids draw more nutrients out of the stalk and into the kernels, and genetic modifications for insect resistance and less lodging results in less-digestible stalks that may also be less palatable, says Anderson.