During wintertime grazing, beef producers should consider supplementing for energy rather than protein, says Brian Rude, beef nutritionist with the Mississippi Agricultural and Forestry Experiment Station.

“A lot of people are trained that they need to supplement for protein, but research has indicated that energy supplementation is more beneficial than protein supplementation,” he says.

The energy type can influence cattle's ability to use feed efficiently and the amount of weight they gain. Energy sources can be starch-based, such as grain, or fiber- or cellulose-based, such as soybean hulls.

Rude recently completed a five-year evaluation of the effects of supplementing corn or hay to animals eating ryegrass. He found no real difference in weight gain, and that supplementing with hay was much more economical than with corn.

“You get the same gain by growing hay that you do with corn,” Rude says. “The cattle aren't really getting any nutrients from the hay, but it is slowing down the rate of passage of the ryegrass, so they are able to obtain more nutrients from the ryegrass they are grazing.”

In ongoing research, Rude is looking at how energy supplementation can increase the number of animals grazing on ryegrass per unit of land.

Fescue is lower in quality than ryegrass, so cattle grazing fescue typically need energy supplementation. Fertilized fescue may provide all the protein cattle need without supplementation, but should be analyzed for content.

“Feeding corn to cattle grazed on fescue improves weight gain. But since the microbial population in the rumen is geared to digesting fescue, it would seem logical that giving them a cellulose-based energy source such as soybean hulls would allow for more efficient utilization of both forage and supplement,” Rude points out.