Cattle Nutrition: Feeding Coproducts: Fact versus Myth
There are more myths about distillers’ grains and gluten feed than I can list. One of the more interesting is that distillers’ grains will cause foot rot and bloat, when in fact distillers’ grains, with their dense mineral content, improve bone and hoof hardness and will reduce the chance of bloat if fed correctly.
Other myths include: soybean hulls are equivalent to ground-up 2"x4" boards; you can’t feed breeding animals coproducts; you can only feed a maximum of 25% coproducts; and coproducts will reduce marbling and yields. None of these are true.
The facts about feeding coproducts are numerous, but three are most important: all creep feeds and show feeds contain at least one coproduct; coproducts have been fed for more than a hundred years; and they can improve performance if used correctly. If not used correctly, they can be lethal, just like corn if fed incorrectly.
Energy values. Distillers’ grains are coproducts from a dry milling plant that produces ethanol and CO2 gas. It has a protein content around 30%. Distillers’ grains are commonly sold in three forms: wet distillers’ grains (33% dry matter), modified distillers’ grains (50% dry matter) and dried distillers’ grains, or DDG (90% dry matter).
Relative to corn, wet distillers’ grains have the greatest energy value: 130%, +/-10%, the net energy value (NEg) of corn. Modified has 112% to 116% the NEg of corn and DDG has 105% to 110%. The greater energy values are due to fat content, but fat and sulfur are the limiting factors to feeding these products.
If fed between 30% and 40% of the complete diet on a dry-matter basis, cattle will perform at their best gain and feed efficiency compared to a corn-based diet or a lesser or greater amount of distillers’ grains.
Distillers’ solubles (or syrup) also come from a dry milling plant. They are the liquid fraction of the distilling process that has had some moisture removed. Syrup usually has a protein content of 18% +/- 4% and a dry matter content of 32%, but a range of 18% to 40% dry matter. The energy content is dependent on the percentage of fat (15% +/- 5%), but it has about 50% more energy than corn.
Gluten feed is a coproduct of the wet milling industry, which produces high-fructose corn syrup and other products. It has a protein content of 18% +/- 6%.
Gluten feed is commonly sold in three forms: wet gluten feed (42% dry matter), Sweet Bran (58% dry matter) and dry gluten feed, which is usually pelleted (90% dry matter). Wet gluten and Sweet Bran, if fed between 20% and 60% of the diet on a dry matter basis, have a NEg value of 100% to 110% of corn. Comparatively dry gluten feed has less energy, only 85% to 90% the NEg value of corn.
Note that these energy values are not taken from lab analysis because of the inaccuracy of the equations used to calculate the NEg values of coproducts. These numbers are calculated from feeding trials done with dry rolled corn, so the NEg values reflect the actual performance response of the cattle. Trials using steam-flaked corn show energy values of coproducts greater than corn but only half the advantage as compared with dry rolled corn diets with the coproducts.
Ki Fanning is a ruminant nutritionist at Great Plains Livestock Consulting, Inc. He founded the consulting service in 1998 with the goal of becoming the premier animal agricultural consulting company for feed manufacturers, producers and entities engaged in livestock production.