Address Minerals When Feeding Co-Products

By Sarah Watson, Livestock Editor
Thursday, December 27, 2007 11:55 AM CST

As more co-products become available and are more commonly used in beef rations, producers need be aware mineral associated with feeding co-product.

“We have some real challenges with minerals,” said Dr. Paul Walker, University of Illinois beef cattle professor at the Beef Cattle Co-Products Conference held in Springfield, Ill. last month.

Levels of some minerals are higher or close to dangerous levels in co-products and can have adverse affects on cattle.

The four primary co-product mineral concerns are low calcium, high phosphorus, sodium and sulfur contents. Phosphorus and sulfur are the real “problem” minerals of the four Walker said.

In corn gluten feed (CGF) sodium ranges up to 1.05 percent on a dry matter basis, and DGS ranges from 0.33 to 0.5 percent. In their diets cattle require between 0.06-0.10 of total diet dry matter, and the maximum level cattle can tolerate is 10 percent of diet dry matter.

“We’re a long ways from that,” he said. “We may want to use minerals with less salt.”

Low calcium and high phosphorus can lead to inverted calcium to phosphorus ratios which can lead to urinary calculi and toxicity problems.

Calcium levels in CGF range from 0.17-0.36 percent and 0.02-0.51 percent in DGS. Cattle require up to 0.50 percent and both CGF and DGS don’t meet the full requirement.

Recorded phosphorus levels in both DGS and CGF are above cattle requirements of up to .38 percent at 0.68-1.22, and 0.42-0.99, respectively. The maximum tolerable level is 1 percent.

“There are some serious problems with too much phosphorus in the diet,” he said.

If phosphorus levels are greater than 0.6 percent, the chance of urinary calculi developing increases significantly.

“We have the potential for urinary calculi not in heifers, but in steers,” he said.

Adding ammonium chloride or calcium chloride to the diet will make cattle drink more water, flushing out the bladder and urethra, a prevention of the calculi.

Phosphorus toxicity is caused when the calcium phosphorus ratio is inverted and can lead to bone resorption and diarrhea.

“This is unlikely, but could happen,” he said. “Most of us are not going to be in that situation.”

From a nutrient management standpoint the increased phosphorus excretion in manure will require more acres for manure application.

“You’re going to need more acres to put on your manure,” he explained.

Sulfur is becoming a more significant problem when feeding co-products.

“It has become a real problem this fall,” he said.

Cattle require 0.08-0.15 percent diet dry matter with a maximum of 0.4 percent. CGF and DGS have recorded sulfur levels as high as 0.72 percent and 0.95 percent, respectively this year.

“We’ve almost doubled the amount of sulfur in distillers,” he said.

Historically DGS concerns began at 40 percent inclusion of the diet dry matter and with the increase of sulfur problems can start at lesser levels.

Polio and brainers are the main concern of elevated sulfur levels. Adding 100-200 milligrams of thiamin per head per day when feeding co-product will prevent most polio problems.

Sulfur toxicity or brainers, used to be a concern at 50 percent inclusion rates, but now that level of concern is just 30 percent. A silent contributor to the sulfur toxicity problem is sulfur levels in water. The combination of the two can make a deadly combination.

“If sulfur levels are high in water, think about stopping at 25 percent dietary inclusion,” he suggested. Walker suggested getting your water analyzed to find out the sulfur content.

He also suggested getting a nutrient analysis on every load of co-products received and date of the analysis quote. Know the source of the analysis information.

“Know if your source is the marketing broker or the plant manager,” he said. Don’t just take the analysis at face value n ask questions.”

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