Macerated Rice Straw for
Feedlot Cattle-01 



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Project Leader and Principal UC Investigators

Richard A. Zinn, professor, Dept. of Animal Science, UC Davis


Rice straw is a major feed resource in some parts of the world. Because of the disposal problems now facing the California rice industry, using rice straw as a feed supplement for livestock is getting increased scrutiny here. Previous research examined whether different field treatments would enhance the value of straw fed to cattle grazing on open rangeland. This project is examining whether a macerator—a mechanical treatment—could also make rice straw more palatable to livestock in feedlots.

Cows.JPG (39565 bytes)The full title of this project is “The influence of maceration and fibrolytic enzymes on the comparative feeding value of rice straw in diets for feedlot cattle.” Its 2001 objective was to construct a large-scale rice straw macerator and to test various settings on the machine to optimize the process.

A large-scale macerator was developed at the University of California’s Desert Research and Extension Center. Macerators increase forage surface area without appreciably decreasing particle size. Rice straw is run between corrugated rolls at differential speed under high pressure. This increases exposure rate of forage to enzymatic degradation.

A series of experiments sought to determine optimal roller speed and ram pressure on the rate of rice straw fiber digestion. With a roller speed of 18:13 rpm and a ram pressure of 900 psi the rate of rice straw fiber digestion increased 28 percent. Researchers attribute this improvement to maceration.


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