Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
5/9/00
Contacts:
Larry McMullen, Jones County Extension, (319) 462-2791,
x1mcmull@exnet.iastate.edu
Sherry Hoyer, Iowa Pork Industry Center, (515) 294-4496,
shoyer@iastate.edu
Project Measures Effects of Reducing Phosphorus by Using Dietary Phytase
CEDAR RAPIDS, Iowa -- Results from a swine demonstration project under way at Kirkwood Community College are helping the swine industry determine the effects of using dietary phytase to reduce phosphorus. Phytase is an enzyme that breaks down a component (phytate) in grains and oil seeds, resulting in more dietary phosphorus being available to the pig. The first of four scheduled trials is done and a second is nearly complete, according to Iowa State University Extension livestock field specialist Larry McMullen. He coordinates the project in cooperation with Arlin Karsten, DVM, and Steve Juhl from Kirkwood. The project was funded by the Iowa Pork Industry Center at ISU.
Reducing the phosphorus content of manure can help lessen manure's offensive odor, as well as reduce the amount of phosphorus being applied to the land base. McMullen said this study was designed with several objectives in mind.
"We want to determine if feeding phytase in swine finishing rations will reduce the phosphorus content of manure, so we're doing manure analysis comparisons between our control and test groups," he said. "We're also comparing feed efficiency, average daily gain, feed cost per pound of gain, and water consumption differences between the two groups."
McMullen said approximately 50 pigs at a beginning weight of about 70 pounds are used in each of the groups. Both groups are divided into three pens, and all six pens are housed in one room of the finishing building within the Kirkwood Swine Unit.
All the hogs are phase fed on a split-sex schedule and the barrows and gilts are rotated on the phytase diet. Feed is measured at the beginning and end of every feeding phase. Liquid manure samples are collected every two weeks from individual pits beneath the control and test groups, and solid manure samples are taken from the slats in the building.
Water consumption was measured by the total room capacity for the first trial and is now monitored separately for the control and test groups. McMullen said the water use data is encouraging.
"Water wastage has been quite low and the consumption rate has been lower than expected," he said. "Even so, pig performance has been excellent."
Initial results show the first test group of barrows gained an average of 2.01 pounds per day compared with 1.95 pounds for the control group of gilts. Feed conversion was 3.33 for the test group of barrows and 3.00 for the gilts in the control group.
The program will end early next year, and McMullen said results would be publicly available.
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