Farm Progress

Feeding DDG? Hold the extra P

Distillers dried grain is a good source of phosphorus.

Karla Jenkins

January 4, 2018

2 Min Read
DIET CONSIDERATIONS: Providing the right type of mineral with diets containing distillers dried grain can alleviate potential health problems and be more cost-effective.Karla Jenkins

Most producers are aware that distillers dried grain is an economical, concentrated source of protein and energy. DDG can also be a good source of phosphorus and often eliminates the need for supplemental phosphorus.

While meeting the phosphorus demands of cattle is important, it is also important to make sure the calcium-to-phosphorus ratio is correct. The recommended ratio of Ca:P is typically 1.5:1 to 2:1 with no less than a 1:1 ratio. If this ratio becomes inverted, cattle can experience urinary calculi, which most cattle producers refer to as "water belly." A blockage develops in the urinary tract preventing the animal from voiding urine.

When phosphorus is overfed, the risk of cattle developing this condition increases. Therefore, removing additional phosphorus from the mineral package or adding calcium may be necessary when DDGs are fed as a protein or energy source.

Secondary to animal health is that adding phosphorus in the mineral package increases the cost. If the requirement is being met by the DDG, then the cost margin is being increased unnecessarily.

A late-gestation 1,200-pound cow requires 0.26% Ca and 0.16% P on a dry matter basis in her diet. If this cow is receiving about 26 pounds of low-quality hay and 1 pound of DDG supplement on an as-fed basis, not only would her protein and energy needs be met, but also Ca and P would be supplied at 0.26% and 0.2% of the diet, respectively. This would supply a 1.3:1 ratio of Ca:P, so supplemental phosphorus would not be needed in the mineral.

A 600-pound growing steer gaining 1.5 to 2 pounds per day would require 0.4% Ca and 0.2% P on a dry matter basis. If the steer was eating 9 pounds of poor-quality hay, 20 pounds of corn silage and 2.5 pounds of dried distillers on an as fed basis, then the calf would have 0.29% Ca and 0.36% P in the diet on a dry matter basis. This ratio is not quite 1:1, and so a producer might want to purchase a mineral with no added phosphorus but that did have added calcium.

DDG is also high in sulfur. Sulfur can inhibit copper absorption when fed in high concentrations. Therefore producers feeding distillers as an energy source (for example, greater than 30% of the dry matter) should consider feeding a mineral with increased copper to enhance copper availability.

Many mineral companies have mineral packages designed to be fed with DDG-based diets, which have added calcium, low or no added phosphorus, and increased copper availability.

Providing the right type of mineral with diets containing DDG can alleviate potential health problems and often be more cost effective.

Jenkins is a Nebraska Extension cow/calf specialist. This report comes from UNL BeefWatch.

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