No need to add Roughage

By: Loretta Sorensen21-1 pg 10

Wet distiller’s grains (WDGS) have enough fiber content that feeders using WDGS can reduce the amount of roughage they add to feed rations.

That’s the conclusion US Meat and Research Center (MARC) researcher Kristin Hales reached in her recent study of fiber content in WDGS.

Hales’ study involved 128 steers fed individually in Calan gates for 175 days. The steers consumed a ration comprised of 25% WDGS on a dry matter basis with a balance of dry-rolled corn and coarsely ground alfalfa hay and a vitamin and mineral supplement.

“I was evaluating the result of reducing roughage in feedlot diets using WDGS,” Hales says. “My theory was that those feeders could save a significant amount of money by reducing the amount of roughage added to feed rations. That is especially true right now with the high cost of grain. If feeders are using WDGS and reduce added roughage, they’re saving on feed costs and reducing the resources used to handle roughage such as alfalfa and silage. So this is a very significant cost savings option.”

When the quantity of roughage is reduced, feeders will also cut costs associated with trucking, unloading and storing additives.

“It takes equipment, fuel and man hours to unload a truck and move roughage to the site where the ration is mixed,” Hales says. “Reducing the roughage quantity means every aspect of that process is less costly. You also reduce things like the dust generated during the grinding process.”

Steers in Hales’ test averaged 746 pounds at the beginning of the 175-day project. Hales maintained a daily record of feed offered and measured and recorded feed refused on a weekly basis. For the duration of the test, body weight was measured at day 0, 35, 70, 105, 140, 174 and 175. Carcass data were also recorded at harvest.

“When the study was completed we found that the steers’ final body weight increased when the percentage of alfalfa hay added ranged from 2% to 6%,” Hales says. “The study also revealed that steers’ body weight actually decreased when between 6% and 14% of the ration was alfalfa. Our analysis also indicated that feed efficiency decreased when alfalfa added was between 6% and 14%.”

In analysis of hot carcass weight, marbling score and the percentage of cattle grading USDA choice or greater, the percentage of alfalfa added to the ration didn’t affect the end result. When alfalfa quantities were between 2% and 6%, yield and quality grade both improved.

“According to those results, the analysis of feed efficiency and average daily gain on alfalfa predict that the best feed efficiency and carcass quality results occurred when the feed ration contained between 3% and 7% alfalfa,” Hales says.

In the feedlot industry, feeders typically add between 8% and 9% roughage to feed rations, depending on whether that’s alfalfa, corn silage, prairie hay, etc. Hales’ study indicates that roughage percentages can be reduced by as little as 2% or as much as 6%.

As part of her test, Hales confirmed that reducing the percentage of roughage in the feed ration containing WDGS didn’t have a negative result in terms of average daily gain.

“As part of our study we wanted to evaluate the quality of the end product. We didn’t want to sacrifice that in changing the content of the feed ration,” Hales says. “Our records show that, in decreasing alfalfa hay to 2% or 6% of dry matter, there was no reduction in average daily gain. Feed efficiency remained steady throughout the study. We are currently repeating a similar study at the MARC feedlot using larger-capacity, more industry-type pens.”

Feeders who are using rations that contain at least 25% WDGS on a dry matter basis can evaluate the level of roughage added to their ration and consider their options for adjusting that percentage.

“If the ration contains at least 25 percent WDGS and proper bunk and cattle management practices are in place there’s opportunity for feedlot operators to save some money by reducing the percentage of roughage added to their ration,” Hales says. “Especially in light of current drought conditions this practice could be a valuable practice for feeders.”   

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