Corn Byproducts Use In Beef Cattle Enterprise
Corn byproducts can be used as either a protein or energy supplement for backgrounding or replacement heifer/cow diets. The energy value of distillers grains is greater than that of corn. The protein content is three times that of corn and distillers grain is a good source of by-pass protein (UIP undegraded intake protein). In addition, distillers grains is a good source of phosphorus. When distillers grains are fed in high forage diets, there is no negative relationship between distillers grain and forage. Furthermore, because the starch in corn has been removed to make ethanol, acidosis is not a concern. With these characteristics, corn co-products appear to be a good fit as a protein or energy supplement in cow diets that are mostly forage.
In the research sited below, distillers grains where fed in amounts that sulfur and fat were not problems. In addition, distillers grains were included in the diets at supplemental level to add energy, protein, or both energy and protein to the diets that were mostly forage.
A two-year study (Martin et al. 2007 Nebraska Beef Report) evaluated feeding dried distillers grains plus solubles (DDGS) during heifer development on growth and reproductive performance. Supplements for both DDGS fed heifers and control heifers provided similar amounts of CP, energy, lipid, and fatty acids. Protein degradability of the supplements differed such that UIP exceeded requirements of DDGS heifers. Heifer pubertal development and overall pregnancy rate were not affected between control and DDGS fed heifers. However, AI conception rate and AI pregnancy rate were improved by feeding DDGS in the heifer development diet. The replacement heifers in this study were supplemented at 0.58% of their body weight on a dry matter basis. As an example, if the average weight of the heifers was 600 lb, then the group was fed 3.5 lb per head per day on a dry matter basis. If dried distillers grains was fed and were it was 90% dry matter, then heifers were fed 4.0 pounds per head per day as-fed (3.5 lb/hd/da divided by .90 = 3.89 lb/hd/da rounded to 4.0). Limestone (40 lb of limestone per ton) was mixed with the DDGS to add calcium to the diet. Heifers in this experiment did not experience sulfur toxicity. The heifers were projected to gain 1.5 lb/da and their actual gain was 1.35 lb/da. This experiment demonstrates that distillers grains, fed at 0.58% of body weight dry matter basis, does not have a negative impact on reproductive performance in replacement heifer diets.
As beef cow producers continue to explore management practices to reduce costs, especially heifer development costs, there appear to be opportunities to develop heifers using crop residues and distillers grains. Distillers grains have a high energy (108% to 112% TDN) and high protein content (30%). In addition, distillers grains fit well as a protein and (or) energy supplement in many grazing situations. Corn residues are a relatively inexpensive feed resource, but are low in protein and energy, especially for growing calves. Beef producers often target a specific ADG when growing calves. DDGS were fed to weanling steer calves grazing nonirrigated corn residue to determine daily gain response and residue intake response to increasing levels of DDGS (from 1.5 to 6.5 lb/day in 1 lb increments; Gustad et al., 2006 Nebraska Beef Report). Daily gain increased from 0.9 (1.5 lb DDGS) to 1.8 (6.5 lb DDGS) lb/day. These results provide information for selecting a DDGS supplementation level to achieve a target gain when calves are grazing corn residue. Although this experiment used steer calves, there is direct application to developing replacement heifers. These data suggest that calves can program feed to a specific ADG based on the amount of distillers grains supplemented while grazing corn stalk residue.
An experiment was conducted using cornstalk residue and supplementation was used as part of the development program for replacement heifers (Larson et al., 2010 Nebraska Beef Report). While grazing corn residue heifers were supplemented with 1 to 2 lb/hd/da dry matter basis of a 28% crude protein cube. Yearling pregnancy rate varied between 84% and 92% and subsequent pregnancy rate as 2-year-olds of these same females ranged between 77% and 100%. The data suggests when heifers were supplemented at the higher rate, reproductive performance was numerically greater. A producer could consider, when it can be economical, using DDGS as the supplement because it is a good protein (30% CP) and energy source.
Spring-calving heifers in mid-gestation grazing residue fields the first 25 days will likely meet both their protein and energy needs and should gain weight and body condition, especially if some corn is available. After the grain has been consumed, protein and energy supplementation appear to be needed. The remaining corn reside is between 53 to 54% TDN and crude protein during this time period will be about 5.3% CP. For the 1,020 pound heifer in mid-gestation and average body condition, energy and protein in the diet are deficient. These heifers are approximately 0.60 to 0.70 pounds deficient in crude protein and 0.7 lb to 0.9 deficient in energy. Because distillers grains are excellent protein and energy source and because there is a calculated deficiency in both protein and energy, it appears to be a good fit.
Lactating, fall-calving cows grazing crop residue need careful attention at least through the breeding season because nutrient needs are high and nutrients supplied from the residue don't meet their needs. In an experiment comparing calving seasons, August calving cows were supplemented 1 lb/hd/da of a 28% protein supplement while grazing cornstalk residue from October to April (Griffin et al., 2010 Nebraska Beef Report). Rebreeding performance was 90%, but percentage of calves weaned per cow exposed was 85.7% for cows supplemented at this rate. Distillers grains could be used as the supplement source in this management strategy.
Corn byproducts can be used as a protein or energy supplement in cow diets. These feeds when fed in high forage diets, do not have a negative effect on how the overall diet is utilized by the beef animal. Over feeding protein is usually not recommended because protein is expensive and any excess protein ingested by the cow is used as energy. Because of the unique energy and protein profiles of corn co-products, it may be economical to overfeed one nutrient to meet the requirement of another nutrient.
Dr. Rick Rasby, Professor of Animal Science
Animal Science, University of Nebraska - Lincoln, Lincoln, NE