Stocking Rates and Grazing Systems
Results from 25-year Wyoming study shared.
by Kindra Gordon for Angus Productions Inc.
CASPER, Wyo. (Dec. 2, 2009) — During the 21st Range Beef Cow Symposium in Casper, Wyo., Justin Derner, shared results from the longest known grazing system and stocking rate study in North America. The study was conducted from 1982 through 2006 at the High Plains Grasslands Research Station near Cheyenne, Wyo.
"Livestock gains were much more responsive to stocking rate than to grazing system," noted ARS rangeland management specialist Justin Derner.
A rangeland scientist with the Agricultural Research Service (ARS) in Cheyenne, Wyo., Derner reported results from the final 16 years of the study, comparing season-long and short-duration rotational grazing at moderate and heavy stocking rates and their effects on yearling beef weight gains and vegetation production.
Highlights included:
• Heavy stocking rates consistently reduced average daily gains by 12% compared to moderate stocking rates. For the study, moderate stocking was 7.5 acres per steer and heavy stocking was 5.5 acres per steer.
• Gains were reduced slightly (6%) with short-duration rotation grazing compared to season-long grazing during the study period.
• Neither stocking rate nor grazing system affected vegetation production for this portion of the study. Derner noted that additional research at this study site has shown that vegetation production is 23%-29% greater with light stocking rates (12.4 acres per steer) compared to moderate and heavy stocking rates.
• Beef production increased with increasing spring precipitation for all stocking rates and grazing system combinations. And, as one would expect, vegetation production increased with increasing spring precipitation for all stocking rate and grazing system combinations.
In closing, Derner noted, “Livestock gains were much more responsive to stocking rate than to grazing system.” He added that research is continuing to try and develop forecast models that will better aid beef production decision making and risk assessments with regard to stocking rate and grazing systems.
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