Ethanol Featured Articles
Impact of Bio-Fuel Industry on Beef Industry: Use in Growing & Finishing Rations
By the Alberta Agriculture and Rural Development. This document is part of the Capturing Feed Grain & Forage Opportunities 2007 Proceedings - "Farming for Feed, Forage and Fuel."
Key Points/Take Home Message
Cereal grain-based ethanol production is projected to dramatically increase in North America from 2000 to 2010.
Concurrently the supply of DDGS as a livestock feed will increase.
Wheat-based DDGS is an excellent source of protein and energy for cattle when fed in balanced rations.
The energy value of wheat-based DDGS appears to be related to dietary inclusion level.
At levels up to 40% of diet dry matter in low to medium energy growing diets, energy value has been shown to be equal to that of barley grain, while economic value may be up to 10% higher.
In finishing diets, at 20 to 25% of diet dry matter, energy value is similar to that of barley grain, however as dietary inclusion levels increase to 60% of dry matter, energy values are reduced due to higher intakes and poorer feed conversions.
When feeding wheat-based DDGS, producers are encouraged to consult a nutritionist to develop rations that result in safe, efficient gains and to develop manure management programs that consider the potential environmental impact from feeding this byproduct of the ethanol industry.
Introduction
Beef producers are starting to hear a lot about the potential of distillers’ gains and other byproducts of the bio-fuel industries as feed sources for their cattle. Since feed typically accounts for 55 to 65 % of operating costs, it is not surprising that many are starting to ask questions regarding cost, nutritional value and supply. Much of the interest in feeding distiller’s grains stems from the rapid increase in ethanol production capacity across North America. For example, in the past five years the United States has increased ethanol production capacity from 1.5 to slightly greater than 6 billion gallons annually with a further 6 billion gallon annual production capacity currently under construction. Similarly in Canada with plants in operation or under construction, we will have a capacity close to 1.5 billion litres in the next 6 to 12 months (Ethanol Producer, 2007). With a national mandate for 5% inclusion of ethanol in unleaded gasoline in 2010, it is fair to say that we will see the continued growth of the ethanol industry in Canada.
With an increased ethanol industry, there is an increased supply of byproducts that can serve as excellent cattle feed. Consider the example of a 100 million litre or larger wheat-based ethanol plant. In the next year, 3 such plants will operate in western Canada, in addition to several corn-based plants of the same or larger size in eastern Canada. These plants will produce approximately 1000 tonnes of dried distillers’ grains with solubles (DDGS) for each million litres of ethanol produced or 100,000 tonnes of DDGS per year for a 100 million litre plant. Thus, it is not hard to understand why beef producers are anxious to learn about the feed byproducts of these plants and how to use them in their feeding programs.
DDGS – What are they and how do they fit?
In order to fully understand the answers to these questions, it is necessary to step back and examine how ethanol and its feed-related byproducts are produced. Most wheat- and corn-based ethanol plants built today incorporate dry milling into the ethanol production stream. Dry milling starts with putting the grain through a hammer-mill or in some cases a roller-mill to break up the whole grain. The processed grain then goes through a series of steps to prepare it for fermentation. These steps include cooking, addition of enzymes, conversion of starch to sugars and finally addition of yeast. During fermentation, the yeast converts the sugars to alcohol and carbon dioxide. Following fermentation, “the beer” is transferred to a distillation column where the ethanol is removed. At this stage the remaining material is called whole stillage and consists of all the components of the original cereal grain (except the starch), yeast cells and added water.
It is this whole stillage that forms the starting point for the various feed related byproducts that can result from an ethanol plant. There are 2 classes of these byproducts. The first is wet byproducts such as wet distiller’s grains and thin stillage, which are formed by simply pressing or centrifuging the whole stillage. Wet distillers' grains contain approximately 30 to 35% dry matter, while thin stillage is quite wet with only 5 to 7% solids. Both of these products are high in protein and energy when considered on a dry matter basis and can be used in growing and finishing rations as well as in wintering cow rations. However, it is important that producers be aware that they must be relatively close to the ethanol plant to make these products work in their rations as transportation costs can become prohibitive due to their high moisture content. Pound-Maker AgVentures Ltd., at Lanigan, Saskatchewan has run an integrated ethanol / cattle feedlot for more than 15 years. Their feeding and management program is an excellent example of how wet byproducts can be used in growing and finishing rations. In their case the wet distiller’s grain is added to the ration, while the thin stillage is fed to the cattle in water bowls. In cooperation with Pound-Maker AgVentures Ltd., the University of Saskatchewan has carried out extensive research documenting the feeding value of wheat-based wet distillers’ grains and thin stillage (Mustafa et al. 2000; Fisher et al. 1999; Ojowi et al. 1997; Iwanchysko et al. 1999).
Dried distiller’s gains with solubles or DDGS are the form of ethanol byproduct that most beef producers in Canada will encounter. Limited research has been carried out with wheat-based DDGS for cattle (Boila and Ingalls 1994). DDGS results from the complete drying at the ethanol plant of the residual whole stillage. The resulting feed has a dry matter content of close to 90%. As such this feed source can be transported great distances and stored without fear of spoilage. The attached table shows the nutrient content of 4 samples of wheat- based DDGS derived from 3 ethanol plants which differ in drying technology. Within and between plant variation in nutrient profile of DDGS can be an issue. In particular, drying conditions can significantly influence protein quality and availability of the resulting product (Kleinschmit et al. 2007). From the table you can see that the nutritional benefits of DDGS arise from the nutrients that are left over after the fermentation process to produce ethanol. In particular nutrients such as fat, protein and fibre are concentrated. A rule of thumb is that nutrients in DDGS that are not metabolized during ethanol production are concentrated approximately 3 fold relative to the original cereal grain. As such phosphorus is approximately 0.35% in wheat and can approach 1% in DDGS. Other minerals such as sulfur and calcium are also concentrated.
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Table 1: Nutrient Content of Wheat-based Distillers’ Dried Grains with Solubles.
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| Nutrient (% Dry Matter) | Plant 1 | Plant 2 | Plant 2 | Plant 3 |
|---|---|---|---|---|
| Dry Matter | 87.2 | 89.7 | 88.5 | 90 |
| Crude Protein % | 39.6 | 42.3 | 42.1 | 39.7 |
| Fat % | 4.7 | 6.6 | 5 | 6.5 |
| Neutral Detergent Fibre % | 29.9 | 35 | 54.8 | 25.6 |
| Acid detergent fibre % | 14.5 | 18.9 | 12.5 | 13.5 |
| Calcium % | 0.14 | 0.12 | 0.13 | 0.3 |
| Phosphorus % | 0.95 | 0.94 | 0.96 | 1 |
| Sulfur % | 0.39 | 0.46 | 0.47 | 0.69 |
When comparing DDGS samples from corn vs. wheat it is important to consider that differences in nutrient content between DDGS derived from different cereal grains are similar to differences between the original cereal grains. For example, wheat has higher protein (i.e. 15%) than corn (i.e. 10%). Similar differences are evident in the DDGS derived from each source (35 to 40% for wheat-based DDGS vs. 27 to 32% for corn-based DDGS). In contrast the fat content of corn-based DDGS is considerably higher than that of wheat (i.e. 6 vs. 11%). As ethanol plants often alter the types of grains they use for ethanol production, it is a good idea that the chemical composition of each lot of DDGS be determined.
With corn-based DDGS, work from the University of Nebraska indicates that the energy value of wet distillers’ grain when fed at 40% of the diet dry matter is approximately 1.4 times that of corn while when dry as DDGS it had a value approximately 1.2 times that of corn grain (Hamm et al. 1994). The high energy value of corn-based DDGS when fed either wet or dry is primarily due to its high fat content.
Concentration of minerals and protein in DDGS can be an issue for cattle feeders. Both protein and phosphorus are high in this product and if we over feed this byproduct in significant amounts, the result can be high levels of nitrogen and phosphorus excreted in the manure. This would require a sound environmental farm plan in order to make efficient use of these nutrients as fertilizer. Similarly high sulfur levels in DDGS contribute to overall sulfur levels in the diet. If diet sulfur levels start to exceed 0.45 to 0.50% on a DM basis, there is potential for "poilo" to develop in cattle. Thus it is a good idea to consult a feedlot nutritionist before feeding these byproducts to any great extent.
Current research:
At both the University of Saskatchewan and the Agriculture and Agri-Food Canada Research Station at Lethbridge, research trials have been conducted to evaluated the performance of cattle fed wheat-based DDGS.
At the University of Saskatchewan the performance of cattle fed wheat-based DDGS as a replacement (0, 5, 10, 15, 20 % diets as fed basis) for barley in both backgrounding and finishing diets. During backgrounding, the control diet consisted of 50% barley silage, 10% grass hay, 10% barley straw, 25% barley grain and 5% protein / mineral supplement (as fed basis). On a dry matter basis, DDGS comprised 8.1, 16.2, 24.2 and 32.1% of the ration. All diets were formulated to a net energy of maintenance (NEm) and gain (NEg) content of 1.52 and 0.93 Mcal / kg of diet DM, respectively, based on the assumption that the energy value of DDGS is equal to that of dry rolled barley. The control diet was formulated to contain a minimum of 12% CP (28% rumen undegradable protein (RUP)) for the backgrounding phase (NRC 1996). Treatments 2 through 4 had formulated CP and RUP levels of 12.8 & 33.7%; 14.84 & 39%; 16.9 & 42.5%; and 18.9 & 45.4%, respectively. Calcium to phosphorus ratios were formulated to range from 1.5:1 to 2:1. All other mineral, vitamin and rumensin levels were formulated to be equal across treatments. Following completion of the backgrounding phase, the cattle were maintained on their original treatments and subsequently moved via a step-up program on to a finishing program. The control diet consisted of 15% barley silage, 80% barley grain and 5% of a mineral vitamin supplement. It was formulated to 13% crude protein and 1.91 and 1.27 Mcal of NEm and NEg, respectively. As in the backgrounding period, treatments 2 through 5 were formulated to the same energy level as the control with DDGS replacing barley grain at 5, 10, 15 and 20% of the diet (as fed basis). On a dry matter basis, DDGS comprised 5.8, 11.7, 17.5 and 23.3% of the ration for treatments 2 through 5, respectively. Estimated RUDP levels varied from 27 to 40% in diets 1 and 5, respectively. Mineral, vitamin and rumensin levels were maintained as in the backgrounding phase.
During the backgrounding period, average daily gain, dry matter intake and feed efficiency was not influenced by increasing level of DDGS in the ration with the exception that cattle fed 5% DDGS had lower intakes and consequently gains. During the first 56 days of finishing, cattle fed the 5% DDGS treatment exhibited superior feed efficiency, likely a result of compensatory gain from the poor performance during the backgrounding period (Table 2). Over the entire finishing period, no effects of treatment were observed on performance or carcass quality. The primary conclusion from this work is that wheat-based DDGS when fed at levels up to 32 and 23% of DM in backgrounding and finishing diets, respectively does not negatively impact performance and that wheat-based DDGS has the energy value at least equal to that of barley grain when fed at the levels used in this study.
| Table 2: Effect of wheat-based dried distillers’ grains with solubles (DDGS) on performance of weaned calves fed to finish at the University of Saskatchewan. | |||||||||||
| Level of DDGS, % As Fed** | SE | P Value | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 5 | 10 | 15 | 20 | |||||||
| Weight (lb) | |||||||||||
| Start of Test | 640.9 | 640.3 | 638.3 | 639.8 | 640.4 | 0.57 | NA | ||||
| End of Backgrounding | 866.6ab | 844.8c | 855.7bc | 875.8a | 880.5a | 6.63 | 0.01 | ||||
| Day 56 of Finishing | 1149.4bc | 1133.5c | 1135.4c | 1167.4ab | 1177.7a | 8.5 | 0.01 | ||||
| End of Test | 1341.7 | 1336.5 | 1325.4 | 1350.2 | 1338.8 | 6.19 | 0.13 | ||||
| Dry matter intake (lb) | |||||||||||
| Backgrounding phase | 16.8a | 16.0b | 17.0a | 17.6a | 17.5a | 0.3 | 0.01 | ||||
| Day 1 to 56 of Finishing | 21.8b | 21.4b | 21.8b | 23.0a | 22.8a | 0.33 | 0.01 | ||||
| Day 56 to End of Finishing | 25.9 | 25.8 | 25.3 | 26 | 25.6 | 0.53 | 0.93 | ||||
| Day 1 to End of Finishing | 24.3 | 24 | 23.9 | 24.8 | 24.5 | 0.31 | 0.33 | ||||
| Average Daily Gain (lb) | |||||||||||
| Backgrounding phase | 2.7ab | 2.4c | 2.6bc | 2.8ab | 2.8a | 0.08 | 0.01 | ||||
| Day 1 to 56 of Finishing | 5.05 | 5.16 | 5 | 5.21 | 5.31 | 0.08 | 0.06 | ||||
| Day 56 to End of Finishing | 3.26 | 3.18 | 2.96 | 3.13 | 2.95 | 0.12 | 0.29 | ||||
| Day 1 to End of Finishing | 4.13 | 4.1 | 3.91 | 4.14 | 4.14 | 0.09 | 0.34 | ||||
| Feed efficiency (ADG:DMI) | |||||||||||
| Backgrounding phase | 0.16ab | 0.15b | 0.15b | 0.16ab | 0.16a | 0.003 | 0.05 | ||||
| Day 1 to 56 of Finishing | 0.232a | 0.241b | 0.229a | 0.227a | 0.233a | 0.003 | 0.01 | ||||
| Day 56 to End of Finishing | 0.126a | 0.123ab | 0.117bc | 0.120abc | 0.115c | 0.003 | 0.05 | ||||
| Day 1 to End of Finishing | 0.17 | 0.171 | 0.164 | 0.167 | 0.169 | 0.002 | 0.2 | ||||
| **Means in the same row with different letters at significantly different. | |||||||||||
At the Lethbridge research station heifer calves were individually fed barley / barley silage feedlot diets with increasing levels of wheat DDGS. During the 55-day backgrounding period, the control diet (0% DDGS) contained 40% barley, 55% silage, and 5% supplement (dry matter basis). The equivalent as-fed formula is 22.5% barley, 2.5% supplement, and 75% silage. Treatment diets during the backgrounding period contained either 20 (plus 20% barley) or 40% DDGS (with no barley). During the 133-day finishing period, five diets were fed with DDGS included at 0, 20, 40, and 60%. The fifth diet contained 60% DDGS with additional calcium to elevate the calcium:phosphorus ratio above 1.5:1. The control diet contained 85% barley, 10% silage, and 5% supplement on a dry matter basis which equates to 74.7% barley, 21.3% silage, and 4% supplement as fed. Control diets contained at least 13% protein with levels increasing up to 27% in the 60% DDGS diet. The addition of DDGS to back-grounding diets did not affect intake, gain, or feed efficiency (Table 3), indicating that in low energy diets, DDGS has a similar energy and economic value as rolled barley.
| Table 3: Performance of cattle fed 0, 20, 40, or 60% DDGS at the Lethbridge Research Station | |||||
| Control | 20% | 40% | 60% | 60%+Ca | |
|---|---|---|---|---|---|
| d 1-55 | |||||
| Animals | 24 | 24 | 72 | - | - |
| Start weight, kg | 326 | 325 | 324 | 324 | 326 |
| DMI, kg/d | 5.82 | 5.79 | 5.86 | - | - |
| ADG, kg/d | 0.95 | 0.96 | 0.98 | - | - |
| Feed/gain | 6.02 | 6.29 | 6.13 | ||
| D 56-188 | |||||
| Animals | 24 | 24 | 24 | 24 | 24 |
| DMI, kg/d | 10.48b | 10.76b | 11.56ab | 11.72a | 11.44 |
| ADG, kg/d | 1.52 | 1.56 | 1.63 | 1.60 | 1.50 |
| Feed/gain | 6.85 | 6.90 | 7.04 | 7.30 | 7.57 |
| D 1-188 | |||||
| DMI, kg/d | 9.12c | 9.31bc | 9.88ab | 10.05a | 9.78abc |
| ADG, kg/d | 1.36 | 1.39 | 1.42 | 1.44 | 1.36 |
| Feed/gain | 6.76 | 6.71 | 6.90 | 7.00 | 7.14 |
| Final weight, kg | 581 | 586 | 591 | 594 | 582 |
| Dressing % | 58.2 | 58.3 | 58.9 | 57.6 | 60.1 |
| Backfat, mm | 10.0 | 14.0 | 12.1 | 11.7 | 11.3 |
| % AAA | 13 | 43.5 | 16.7 | 16.7 | 25 |
| abc - Values in the same row followed by different letters differ (P < 0.05) which means greater than 95% probability differences are due to treatment. | |||||
During the finishing period, there was no effect of the extra calcium in the 60% DDGS diet so this treatment was removed from the statistical analysis. In the remaining diets, intakes linearly increased (P = 0.003) with increasing levels of DDGS. Higher intake is likely due to the reduced levels of the rapidly fermented starch from barley that was displaced by the DDGS. Elevated protein levels have also increased intakes in some trials. Rate of gain increased slightly (linear P = 0.13), but feed efficiency declined linearly (P = 0.04) with increasing levels of DDGS. By comparing performance of cattle fed the control and 60% DDGS diet during the finishing period, economic and nutritional value was calculated. Despite the linear reduction in feed efficiency with increasing levels of DDGS, it still had 95% the economic value of rolled barley due to its higher dry matter content and the higher gains it provided. Nutritionists might be interested to know that assuming a NEm and NEg content of 2.06 and 1.40 Mcal/kg for rolled barley, these results indicate that energy content of DDGS averaged 1.87 and 1.23 Mcal/kg, respectively. Energy content was slightly higher than barley when DDGS was included in backgrounding diets as was its economic value (10% higher than rolled barley). Levels of backfat and AAA carcasses were highest on the 20% DDGS diet and lowest on the control diet but these differences were not statistically significant. Based on these results it appears that DDGS had little effect on carcass fat but more cattle may need to be assessed to determine the potential impact of DDGS on carcass quality.
Conclusions
Wheat-based DDGS is an excellent source of energy and protein for growing and finishing cattle. This bproduct can be used in backgrounding diets at levels up to 40% of the diet dry matter with no adverse effects. Energy value is equal to that of barley while economic value is up to 10% higher under such feeding situations. The magnitude of this economic value will fluctuate with the relative price differential between DDGS and barley. In finishing diets, energy value is related to inclusion level. At 20 to 25% of diet dry matter, energy value appears to be equal to that of barley grain. At higher inclusion levels (i.e. 40 to 60% of diet dry matter), feed intake increases, efficiency of feed use is poorer, thus reducing the energy value relative to barley. Producers are encouraged to consult a nutritionist for assistance when feeding DDGS-based diets and to develop sound manure management programs.
Acknowledgements
Appreciation is expressed to Saskatchewan Agriculture and Food, Husky Energy and Pound-maker AgVentures for funding research at the University of Saskatchewan and the Canadian Cattlemen’s Association for funding work at the Agriculture & Agri-Food Canada research station at Lethbridge.
References
Boila, R.J. and J.R. Ingalls, 1994, The Ruminal Degradability of Dry Matter, Nitrogen and Amino Acids in Wheat-Based Distillers’ Grains in sacco. Anim. Feed Sci. Techn. (48):57-72.
Kleinschmit, D.H., J.L. Anderson, D.J. Schingoethe, K.F. Kalscheur, And A.R. Hippen. 2007. Ruminal and Intestinal Degradability of Distillers’ Grains Plus Solubles Varies by Source. J. Dairy Sci. (90):2909-2918.
Mustafa, A.F., J.J. McKinnon, and D.A. Christensen. 2000. The Nutritive Value for Ruminants of Thin Stillage and Wet Distillers’ Grains for Ruminants – A Review. Asian-Aus. J. Anim. Sci. (13) 1609-1618.
Fisher, D.J., J.J. McKinnon, A.F. Mustafa, D.A. Christensen, D. McCartney. 1999. Evaluation of Wheat-based Thin Stillage as a Water Source for Growing and Finishing Cattle. J. Anim. Sci. (77):2810-2816.
Ham, G. A., R. A. Stock, T. J. Klopfenstein, E. M. Larson, D. H. Shain, and R. P. Huffman. 1994. Wet corn distillers byproducts compared with dried corn distillers grains with solubles as a source of protein and energy for ruminants J Anim Sci 1994 72: 3246-3257.
