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United States Department of Agriculture

Agricultural Research Service

Title: Forage Macro and Trace Mineral Concentrations from Pastures Fertilized with Broiler Litter

Authors
item Coffey, Ken - UNIV OF AR
item Humphry, J. Bryon - UNIV OF AR
item Sauer, Thomas
item Goodwin, Harold - UNIV OF AR
item Moore, Phil - USDA-ARS
item Johnson, Zelpha - UNIV OF AR
item Kegley, Elizabeth - UNIV OF AR
item Mc Beth, Levi - UNIV OF AR
item Mc Ginley, Brad - UNIV OF AR
item Coblentz, Wayne - UNIV OF AR

Submitted to: American Society of Animal Science Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: July 25, 2002
Publication Date: N/A

Technical Abstract: Four farms in NW Arkansas and NE Oklahoma that routinely applied broiler litter were monitored for nutrient cycling from April 2000 to February 2001. The four farms had a forage base of bermudagrass and cool-season perennials or annuals, and initial soil test phosphorus (STP, Mehlich 3 extract) levels of 230, 282, 526, and 636 kg/ha. Random forage samples were gathered monthly during normal grazing and analyzed for macro and trace elements, but were not gathered when pastures were being stockpiled for hay. Mineral concentrations within farm were averaged across sampling dates and compared with the requirements of gestating and early lactating beef cattle using a t-test. The equivalent ratio of K to Ca +/ Mg was calculated to indicate the likelihood of grass tetany problems. Mean forage Ca, P, S, Co, and Fe concentrations from each farm exceeded (P < 0.05) lactating cow requirements. Forage Mg concentrations from the farm with the highest STP exceeded (P < 0.05) the Mg requirement for lactating cows, but the other three farms exceeded (P < 0.05) only the Mg requirement for gestating cows. Only the two farms with the lowest STP had average grass tetany ratios below (P < 0.05) 2.2, but every farm had grass tetany ratios above 2.2 when sampled in the spring. The farm with the lowest STP had inadequate (P < 0.05) forage Cu concentrations. Producers grazing broiler litter amended sites should be able to reduce Ca and P supplementation, but should provide adequate Mg in the spring.

Last Modified: 10/22/2014
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