When drought limits forage availability, supplemental feeding on pasture can be economical, says University of Nebraska animal scientist Rick Rasby, PhD.
Rasby recommends, however, that ranchers consider these points:
• They must have the labor and equipment to deliver the feed.
• Feeding in bunks can minimize feed waste, but feeding on the ground allows producers to move cattle around the pasture to improve forage utilization while reducing erosion.
• The selected feeds must be relatively cheap compared to total pasture costs.
• Because the cattle continue grazing, the supplemental feeds must not have a negative effect on forage digestion.
By substituting an economical feed that does not limit forage digestion, producers potentially can increase stocking rate, spreading pasture costs over more cows, or graze available pastures for a longer period of time. Rasby says harvested forages such as alfalfa, grass hay or summer annuals can replace grazed forage without a negative impact on the total digestibility of the diet. However, harvested forages typically are expensive during drought, and cows often won’t eat harvested forage until grass in the pasture is depleted. Grains such as corn are not a good choice, even if the cost is attractive. Their high starch content tends to lower rumen pH and reduce forage digestibility.
University of Nebraska researchers have studied supplementing mixtures of wet distillers’ grains mixed with low-quality hay or crop residue in an attempt to replace grazed forage, without removing the cattle from the pasture. Corn distillers’ byproducts are very palatable, and mixing them with low-quality forage or crop residues has been shown to increase consumption of low-quality roughage and replace consumption of standing forage. Trials comparing various feeds have indicated a ratio of 30 percent wet distillers’ grains to 70 percent crop residues is the optimum blend to get the most forage replacement. Using this combination of byproduct and roughage, producers can estimate that every dry-matter pound of the combination fed will replace a half-pound to a pound of pasture forage on a dry-matter basis.