Paul Beck, Oklahoma State University State Extension Beef Nutrition Specialist
After the driest September on record, last night we got what my dad would have called a “million-dollar rain”. For producers relying on winter pasture to grow purchased or retained calves this may be what was needed to give us the prospect of at least some wheat grazing, although probably a month later than normal and not as much fall forage production as what we normally would like. We are already 40 to 50 days delayed in planting our graze out wheat acres and 30 days delayed in planting our dual-purpose wheat, which will limit our forage production potential this fall and winter.
Over the last few weeks as I was driving across Oklahoma, you could really tell who was planting wheat from long distances because of the dust clouds across the horizon. Many farmers were dusting in wheat as fast as they could ahead of this predicted rain. A week ago, areas of central Oklahoma got rainfall ranging from 0.3 inch to 3 or more inches. Producers that had planted ahead of this rain were able to get stands in most of these plantings. If it was not planted before this rain, planting was likely delayed until it was dry enough to get across the fields again. For the prospects of late fall or winter grazing, timing is critical and any delay can have large impacts on forage production.
Our goal should be to stock calves on wheat pasture during the fall and winter so that they have 5 pounds of forage dry matter per pound of calf bodyweight. So, for a 500-pound calf our goal is for him to have 2,500 pounds of forage dry matter available at turnout. This forage allowance will maximize steer weight gains during the fall and winter grazing period. Lower forage allowances are associated with lower performance, but even at 3 to 3.5 pounds of forage per pound of steer bodyweight we have seen gains of 2 pounds per day.
A good rule of thumb is wheat forage has about 200 pounds of dry matter per inch of height, so for 2 acres/steer stocking rate pastures should be 6 to 8 inches tall when we turnout. If pastures are only 4 to 5 inches tall at turnout, we would need 3 acres per steer to meet this goal, we should provide supplemental feed to stretch forage supplies, or we can live with lower calf performance.
So, what are our chances to get any pasture this fall and winter? Dr. Brett Carver conducted research several years ago indicating that wheat growth averaged 3.3 pounds per acre per growing degree day through the fall. A growing degree day is the accumulated heat units above a growth threshold temperature (42° F for wheat) and is calculated by the average daily temperature – 42 times the number of days. Wheat that was up before this latest rain, has the potential to reach 1,000 pounds of forage dry matter per acre by Thanksgiving, if we have our normal average daily temperatures for the rest of the month of October and through November. Wheat that was dusted in ahead of these storms will probably be delayed or have less forage production by a week or 10 days, depending on when it comes up and starts actively growing. Prospects for wheat acres that were not planted, and were relying on these storms to allow planting in ideal soil moisture conditions are completely at the mercy of when tractors will be able to roll across these fields.