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AU Researcher Looks for More Efficient Ways to Feed Broiler Litter in Cattle Diets
AUBURN, Ala.— More than a few Alabama cattle farmers are using broiler litter diets in their operations, and as the number of broilers produced in this state continues to grow, so will the availability of litter, according to Darrell Rankins, associate professor of animal and dairy sciences in Auburn University's College of Agriculture.
"A lot of producers feed broiler litter, and because it's so economical, growers are going to continue to use broiler litter-based diets in the future," he said.
For this reason, Rankins has done several studies in recent years, attempting to understand how some aspects of litter diets for wintering brood cows and stocker cattle can be altered to produce the best results.
For example, he conducted a study through the Alabama Agricultural Experiment Station (AAES) in 1996 showed that no hay added to litter-based diets resulted in greatly reduced weight gains in stocker cattle.
Though intake did not vary, steers fed a standard broiler litter diet of 50 percent litter and 50 percent corn supplemented with 3.5 pounds of hay per day gained about twice as much per day as steers fed the standard diet alone. He found that the addition of hay to a broiler litter diet did not necessarily increase gains, but that the lack of hay in the diet suppressed gains.
It was apparent that some fiber source was necessary in these diets, but the question was how much and which fiber would be best? Two more AAES studies were done attempting to answer that question.
The first compared the standard 50 percent litter, 50 percent corn diet without hay to a standard diet supplemented with three pounds of hay every day, a standard diet supplemented with the same amount of hay twice per week and a standard diet plus free choice hay. From this study, it was observed that the most efficient and economical gains were produced by the diet with free choice hay.
The second study compared diets supplemented with hay or peanut hulls, both fed daily at a fixed amount or free choice. The best daily gains were shown by steers fed diets supplemented with hay, but the most economical option was the diet with free choice peanut hulls.
"The cattle need some kind of roughage, and it doesn't necessarily have to be high quality roughage to produce the needed results," Rankins said.
Yet another study questioned the feasibility of replacing one-fourth or one-half of the corn in the standard diet with soybean hulls, because soy hulls are cheaper than corn and can provide similar results under some conditions.
"Soy hulls have less energy than corn, but the way they are digested in the rumen makes them a good supplement to a fiber-based diet," Rankins said. Whereas corn can cause rumen pH to fluctuate, pH in the rumen stays more consistent when soybean hulls are digested.
The diet containing the most soybean hulls, 25 percent, produced the fastest gains and was most economical, Rankins said, indicating that possibly even more of the corn could be replaced with soy hulls for better results.
Another area of broiler litter feeding that Rankins has studied is controlling the incidence of milk fever in wintering brood cows fed litter diets. Milk fever is a calcium deficiency that results from increased demands from milk production, and it is more likely to occur in older and higher milk producing cows that are fed litter diets.
Adding ammonium chloride, which is sometimes used in the dairy industry to prevent milk fever, was not effective. Rankins suggests that if milk fever is a problem then the producer should consider removing the cows from litter for 60 days prior to calving.
More studies of broiler litter feeding are in the works at Auburn University: replacement of corn with higher levels of soy hulls, using soy hulls in brood cow diets and replacement of corn with molasses in litter-based diets.
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By:
Anna M. Lee
