Patience is a virtue for many things in life, and it’s certainly a desirable trait when grazing small grain forages.
“Research indicates that forage intake and animal performance is limited when pastures have below 850 to 1,000 pounds of forage dry matter per acre,” notes Paul Beck, a beef nutrition specialist with Oklahoma State University Extension. “The most success in a small grain forage grazing system is achieved if the start of grazing is delayed until forage is ready and grazing management allows for adequate leaf area for forage regrowth.”
Overgrazing and putting animals on wheat pastures too early limits animal performance and reduces pasture production. If pastures are below 1,000 pounds of forage dry matter, Beck advises to delay turnout of stockers until pastures have accumulated additional growth.
The beef nutritionist explains that wheat forage grows at 3 to 3.5 pounds of forage dry matter per acre for each growing degree-day (GDD) accumulated. A GDD is defined as the average daily temperature minus 40°F. For example, if on a given day the high temperature is 65°F and the low temperature is 45°F, the average daily temperature is 55°F, and 15 GDDs accumulate (55 - 40 = 15).
Wheat is expected to produce 45 to 52 pounds of forage dry matter per acre with 15 GDDs. So, 10 extra days of growth would be needed to get a pasture from 400 pounds of forage dry matter per acre to at least 850 pounds of forage per acre if 15 GDDs were accumulated each day during this period.
“Setting stocking rates on wheat pasture in the fall and winter has a large impact on the performance of growing calves and will influence the productivity of pastures during the spring,” Beck says.
Ten years of experiments were used to determine the average daily gain (ADG) of animals based on initial forage allowance. Forage allowance is defined as the pounds of initial forage dry matter per pound of initial bodyweight. A maximum ADG of 2.7 pounds per day can be expected with 5 pounds of forage dry matter per pound of initial calf bodyweight, and an ADG of 2 pounds per day might be realized at an initial forage allowance of approximately 2.4 pounds of forage dry matter per pound of initial calf bodyweight.
An easy rule of thumb for wheat pasture is 150 to 250 pounds of forage dry matter per inch of plant height. To make the math easy, Beck uses about 200 pounds of forage dry matter per inch.
Pastures that are 6 to 7 inches in height would have about 1,200 to 1,400 pounds of forage dry matter per acre. A 500-pound steer should have 2,500 pounds of forage dry matter available at turnout (500 x 5 pounds of forage dry matter allowance) to realize optimum performance.
In this situation, about 2 acres of wheat pasture is needed to meet steer performance goals. When forage allowance falls below 2 pounds of forage per pound of steer bodyweight, Beck recommends using supplemental feeds to make up for the nutritional shortfall.