Paul Beck, Oklahoma State University State Extension Beef Nutrition Specialist
Dual purpose wheat pasture for grazing and grain production is a major agriculture enterprise in Oklahoma and the Southern Great Plains. Research at OSU in the 1990’s showed that the first hollow stem is the critical stage to minimize grazing damage to grain yields. Damage to grain production is dependent on many factors, but can range from 1 to 5% per day grazing past first hollow stem.
First hollow stem is affected by the genetics of the wheat variety and environmental factors. The Oklahoma Mesonet has tools available to estimate the percent of wheat crops that have reached the first hollow stem based on actual local conditions or one to two week projections and variety maturity http://mesonet.org/index.php/agriculture/category/livestock/cattle/hollow_stem_advisor. Varieties may vary by as much as 3 weeks in date of first hollow stem, so producers are encouraged to be familiar with the maturity rating of the variety they are using and when considering a dual-purpose grazing and grain production system select wheat varieties that are rated as medium, late or very late in first hollow stem date.
To check for first hollow stem:
- Go to nongrazed area and dig up four to five plants.
- Grazing delays maturity, so finding ungrazed areas is important for accurate assessment. Ungrazed areas can be found in field corners or areas just outside of the electric fence.
- Select the largest tiller from the plants.
- Split the stems with a razor or box cutter starting at the base.
- At First Hollow Stem, the hollow stem is 5/8th of an inch below the developing wheat head (the diameter of a U. S. dime).
- Check for hollow stem below soil surface, because much of the hollow stem will be below the soil surface.
More information can be found in the Oklahoma State University Cooperative Extension Service Factsheet PSS-2147 First Hollow Stem: A Critical Wheat Growth Stage for Dual-Purpose Producers at https://extension.okstate.edu/fact-sheets/first-hollow-stem-a-critical-wheat-growth-stage-for-dual-purpose-producers.html.
Dr Jeff Edwards talked about identifying first hollow stem and the Mesonet’s First Hollow Stem Advisor tool on a classic SunUpTV episode from February 7, 2015. https://www.youtube.com/watch?v=YnxA6BLgo48