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New study puts spotlight on ethanol distillers' grains for cattle

Date posted: March 5, 2007

CAPAEI-backed research examines performance, carcass and manure implications.

Dr. Tim McAllister

Eye on the sky. That has been the focus of the debate surrounding the boom in ethanol production and its environmental implications. But another critically important factor is what happens on the ground.

With wheat "distillers' grains" – a byproduct of ethanol production – becoming broadly available as a feed source for cattle in Western Canada, the unknown effects of these grains on manure composition could substantially change the requirements of manure management plans.

"Feeding wheat distillers' grains as an energy source has major implications for the flow of nutrients out onto the land," says Dr. Darryl Gibb, a ruminant nutritionist at the Agriculture and Agri-Food Canada (AAFC) Lethbridge Research Centre.

"When starch is pulled out of the grain in the ethanol fermentation process, we basically triple the level of the non-starch nutrients. As a result, the manure resulting from feeding distillers grains is expected to have quite a bit more nitrogen and phosphorous than manure resulting from feeding conventional barley grain. We need to understand how much and what that means for modifying manure management plans."

Pioneering study supported by CAPAEI

To address that concern, Canada's Agricultural Producers Addressing Environmental Issues (CAPAEI) is funding a pioneering, ground-breaking study co-led by Gibb and Lethbridge Research Centre colleague Dr. Tim McAllister, a ruminant nutritionist and microbiologist. The scientific team also includes ruminant nutritionist Dr. Erasmus Okine of the University of Alberta and Lethbridge Research Centre environmental health and manure management researchers Dr. Xiying Hao and Dr. Frank Larney.

The scientists are conducting a feeding trial to evaluate the effect of wheat distillers dried grains on cattle performance and carcass quality, as well as on manure concentrations of nitrogen and phosphorous.

"This trial will help individual cattle producers evaluate the nutritional value of distillers' grains and the implications for their manure management plans," says Gibb. "It will also provide the beef industry with information on whether feeding distillers' grains is likely to have a positive or negative influence on carcass quality."

Increasing energy prices and government incentives are driving a major increase in North American ethanol production. In Canada, Husky Oil recently opened a 130 million litre per year plant in Lloydminister, Sask., and has announced plans to expand its Minnedosa, Man., plant to a similar size. The Alberta Government has also announced an incentive program for the expansion of the bioenergy in Alberta.

"The size of the Husky Oil ethanol plants, plus their competitive advantage with respect to drying costs, dictates that the majority of the distillers' grains will be marketed as dried distillers' grains with solubles," observes McAllister. "The Lloydminster ethanol plant alone is estimated to use 400,000 MT of wheat, resulting in the production of about 130,000 MT of distillers' dried grains. This could represent the greatest change in how we feed cattle in Western Canada in the last 40 years."

Understanding a new diet staple

For the agriculture sector, the domino effect triggered by the ethanol juggernaut is expected, at least in the near term, to mean a spike in grain prices and related tighter margins for livestock production. But massive amounts of distillers' grains created by this production may offer cattle producers a comparatively economical alternative feed source.

In the 200-day feeding trial, which started in early December, the researchers are feeding typical feedlot diets to 120 individually housed yearling heifers at the individual feeding barn at the Lethbridge Research Centre. Distillers' dried grains are included at zero, 10, 20, 40 or 60 percent of diet dry matter in finishing diets, and the researchers will examine resulting differences in weight gain, carcass characteristics and manure composition.

"The most obvious question is what will be the nutritional value of the distillers' grains compared to barley, but the environmental implications are just as important, if not more so," says McAllister. "We know distillers' grains provide high levels of protein, nitrogen and phosphorous. But documenting animal performance with those excess levels will provide the cattle industry with new information required to properly utilize the distillers' grains in their feeding programs."

Honing in on value

In part, the project expands on initial research by Dr. John McKinnon of the University of Saskatchewan, in which preliminary results have shown performance from wheat distillers' grains to be superior to that predicted by nutritional models. The CAPAEI-backed study examines higher levels in an attempt to document the maximum amount that can be included in the diet without adversely affecting growth or carcass quality.

"McKinnon's work showed no negative effects on performance when distillers' grains replace the barley, but in his finishing diet, he was using distillers' grains at between 20 and 25 percent of the dry matter, so we're going considerably higher," says Gibb.

"Theoretically, because distillers' grains have a higher concentration of fibre, we would predict that factor would lead to lower performance in the animals," says Gibb. "However, because fibre in wheat distillers' grains – that is, wheat bran – is very digestible and the product is higher in oil and dry matter and requires no processing, feeding value may be higher than laboratory analysis suggests. Our study will help work towards defining what will be the economical level where it makes sense for producers to utilize the distillers' grains."

This "fibre factor" is a major reason the cattle feeding sector is likely to be the livestock market of choice for distillers' grains, notes Gibb. "Beef producers are fortunate that cattle have four stomachs and can better utilize the higher concentrated fibre than monogastrics can."

McAllister recently attended a meeting in the U.S. where the use of corn distillers' grains in feedlot cattle diets was the main research focus.

Research with corn distillers' grains has examined the effects of up to 40 percent of distillers' grains used as dry matter, showing no negative effects on performance, notes McAllister. "We're hopeful of similar positive effects for wheat distillers' grains, but with the higher levels we're examining we do expect to hit a break point where performance goes down. For example, we know that cattle don't grow as well on light weight barley as compared to heavy weight barley because of the lower starch content. Presumably, removal of the starch during ethanol production will reduce the value of distillers' grains as compared to wheat, but the growth performance in cattle at the distillers' grains levels examined so far is already higher than many researchers would have predicted."

Corn vs. wheat

Distillers' grains are not new to ruminant feeding, points out McAllister, but in the past they were used mostly in dairy production as a protein source. "Now we're taking an entirely different approach, by looking at feeding the distillers' grains mainly as an energy source."

Corn distillers' grains have been studied and shown to have strong feeding potential, but aside from the work by McKinnon there has been little research into wheat distillers' grains.

"The U.S. ethanol industry is based on the distillation of corn, while ours is based on the distillation of wheat, so there may be some differences," says McAllister. "But we don't suspect the differences will be huge. There are definitely some differences in the type and content of protein which will be higher in wheat distillers' than in corn. Feeding distillers' grains as an energy source may minimize differences in animal performance between these two types of distillers but there could still be differences in the flow of nutrients into the manure."

One difference that may prove notable is oil content factor, since corn has roughly twice as much oil content as wheat, says Gibb. "Oils contain over twice as much energy as carbohydrates, so that difference could play a part in differentiating the two products."

The potential added value of distillers' grains is more than just higher dry matter content with no need to process, says Gibb. "Wheat bran, which makes up most of the fibre in distillers' dried grains, is highly digestible. That contributes to its value. The increased oil content also adds nutritional value."

Wet vs. dried

A more important comparison for the western Canadian cattle industry may be looking at different treatments of the distillers' grains, says Gibb. While Husky Oil dries its distillers' grains, some plants, such as the PoundMaker plant in Lanigan, Sask., provide wet distillers' grains. The PoundMaker plant produces approximately 13 million litres of ethanol per year.

"When you feed the distillers' grains directly to the cattle in a wet form, that makes a big difference," says Gibb. "But if you're feeding the wet material you've got transportation issues, because you can only afford to transport so far. That's why at least at first it appears the dried distillers' grains is what most western Canadian producers will be dealing with."

Still, the dynamics could change further down the road depending on the rise in ethanol and other potential biofuels, says McAllister. "We hope to look at different treatments of distillers' grains in future studies. There's a large plant that's even bigger than the one Husky has now, which is scheduled to be producing in Red Deer in the next few years, so that could be a big factor if they decide to go with a different treatment. Ultimately, you need to look at the specific characteristics of the distillers' grains that are coming out of each of the different plants."

Canada's Agricultural Producers Addressing Environmental Issues (CAPAEI) is a federal initiative funded through AAFC's Greencover Canada program. It is designed by, and administered through the Soil Conservation Council of Canada. The Canadian Cattlemen's Association coordinates the delivery of the program to beef cattle producers.