We finally got enough rain in parts of Oklahoma for our wheat and other cool-season annuals to start emerging. This is extremely late for our normal wheat grazing programs since for a “good” wheat pasture year, we expect to turn out on Nov. 1. The late start really limits the prospects for being able to graze cattle on wheat this winter.
Overgrazing and starting too early will limit animal performance and reduce the total overall production of these pastures. My normal recommendation is to wait until small grains are 4-6 inches tall before turning out cattle on pasture. Using a rule of thumb of about 200 pounds of forage dry matter per inch in height, this should provide us with 800-1,200 lbs. of forage dry matter per acre. This should allow adequate forage for steers to gain 2 lbs. per day when stocked at 2 acres per steer.
With our late start, can we reach this level of forage growth this winter?
• Wheat forage grows at 3-3.5 lbs. of forage dry matter per acre for each growing degree day.
• A growing degree day equals the average daily temperature, 40 F.
• The average daily temperature for November in central Oklahoma is 50 F, with 61 F average high and 39 F average low temperatures.
• Wheat would be expected to produce 30-35 lbs. of forage dry matter per day this month.
• So, we may be able to start grazing winter pastures in early December this year.
• Other cool-season annuals (cereal rye and triticale, for example) are more productive at lower temperatures, so forage accumulation should be higher.
• This rule of thumb relies on unlimited soil nutrients and moisture, so unfertilized pastures will not reach these targets, and we need to keep getting timely rains.
We can’t rely on much forage production in December and January because the average temperatures are right at or below the 40 F threshold, so we need to be sure to let as much growth accumulate before we turn cattle out as we can. Forecasts indicate we have a 33-50% chance of having above-average temperatures in Oklahoma for the next three months. Things may be better than expected.
Holding cattle off pastures this fall and managing grazing to produce adequate leaf area for regrowth following grazing will improve productivity in the late winter and spring. This will shorten our hay feeding season later in the year. — Paul Beck, Oklahoma State University Extension beef nutrition specialist
