Montana Grazing Animal Unit Month (AUM)/Acre Estimator

Range and Pasture Technical Note Number MT-32 (Revision 2)

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Range and Pasture Technical Note Number MT-32 (Revision 2)(PDF; 68 KB)

Revised September 2008

• Background
• Anticipated Uses of the AUM Estimator
• Definition of AUM/Acre Parameters
• Deriving Animal Requirements
• How to Use the AUM Estimator
• Data Sources for Using the AUM Estimator
• Soil Maps
• Soil Survey Area Estimated AUM/Acre Tables (viewable, printable, or GIS usable download).
• References for Using the AUM Estimator

Background

Rangeland and dryland pasture Animal Unit Month (AUM) estimations are needed for a variety of conservation planning and data applications.

Anticipated Uses of the AUM Estimator

• Montana Department of Revenue - Application for Agricultural Classification of Lands, AUM calculations calculations (must use the Below Normal AUM/Acre values for qualifying agricultural land). .
• • Any other uses where having a reasonable estimate of grazing potential facilitate soil and water conservation activities, especially when weather doesn’t permit on-site vegetation sampling.

Definition of AUM/Acre Parameters

• Below Normal AUM/Acre values – lower precipitation and possibly cooler temperatures at a critical time that leads to lower production for the historic climax or near climax plant community. These AUM/Acre values should be used for AUM estimation where the plant community is at less than the historic climax or near climax condition or similarity index.
• Normal AUM/Acre values – precipitation and temperature that allows for normal plant production for the historic climax or near climax plant community.
• Above Normal AUM/Acre values – higher than normal precipitation as well as adequate temperatures that allows higher plant production for the historic climax or near climax plant community.

If you have any questions, please contact:

Jon Siddoway, Rangeland Management Specialist
Phone: (406) 587-6790
Email: Jon.Siddoway

Ronald Nadwornick, State Resource Conservationist
Phone: (406) 587-6998
Email: Ronald.Nadwornick

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Last Modified: 09/25/2008