October 26, 2010
Stocking rate, number of cows per acre of pasture, requires careful figuring, says MU forage specialist
COLUMBIA, Mo. - A beef cow eats 3 percent of her body weight in forage daily. A 1,200-pound cow will need 36 pounds of grass per day.
Those facts are a start for calculating stocking rates of cows per acre.
"My most frequently asked question is, 'How many cows should I have?'" says Rob Kallenbach, University of Missouri Extension forage specialist.
"How many cows? That's the last question in a series of questions to determine stocking rate," Kallenbach says.
The answer depends on whether the farm is located in north Missouri or the Ozarks. The type of soil, fertility and forage species affect the pounds of dry matter available per acre.
Also, cow size is important. A 1,500-pound cow needs 50 percent more forage per day than a 1,000-pound cow. Many questions must be answered to determine "How many cows?"
Kallenbach will talk about variables affecting stocking rate at the Missouri Forage and Grassland Conference, Nov. 8-9, at Lake Ozark, Mo. His topic is "Matching Stocking Rate to Forage Growth."
There is no more important question in determining the success of a grass farm than the stocking rate, Kallenbach says. Investment in land and cattle must be balanced for best profit potential.
With the correct stocking rate, producing the optimum pounds of beef per acre will help the bottom line.
Rules of thumb can be used to determine production and stocking rates.
A farm with good pasture, not great pasture, may grow 3 tons of forage per acre on an annual basis. That lightweight cow will need 5 tons of forage. But if the cow has a calf, as expected, that will increase the forage demand to raise the calf for six months to 7.5 tons.
That shows a need for 2.5 acres per cow-calf pair. But wait, Kallenbach says. That assumes the cattle are totally efficient in harvesting forage, wasting none.
"Cows are never 100 percent efficient," Kallenbach says. "Really good operations get 70 percent efficiency. Much more common is 40 percent consumption."
The calculations go on. Different equations will be needed for dairy cows, stocker calves and other types of livestock.
"If there is any one thing we've learned about stocking rates it's that management-intensive grazing (MiG) pays," Kallenbach says. "Controlled grazing using hot-wire paddocks to subdivide pastures can double grazing efficiency."
A side benefit of MiG is that more tonnage of higher-quality forage results from proper management. Alternating grazing with resting allows more forage growth.
Also, managers will learn the need for measurements for efficient production. That includes measuring forage growth and weighing calves. Actual measurements rather than rules of thumb help gain extra profits from grasslands.
"Our best producers are using rising-plate meters to estimate the dry-matter content in each grazing paddock," Kallenbach says. "Measurements guide actual stocking rates."
After all calculations are done, Kallenbach advises stocking at about 90 percent. That leaves a safety margin for a dry spell.
To put his 45-minute talk into perspective, Kallenbach tells how much there is to learn. "A forthcoming book on grazing by MU Professor Jerry Nelson devotes 160 pages to telling research results on stocking rates."
For MFGC members, the full conference registration fee, which includes the banquet and two lunches, is $95 plus $45 for spouse. Nonmember fee is $115. Advance registration is required. Contact Joetta Roberts at 573-499-0886 or firstname.lastname@example.org.
The conference will be held at the Resort at Port Arrowhead, Lake Ozark. Check-in starts at 10 a.m., Nov. 8, and the program ends at 3 p.m., Nov. 9. A block of rooms has been reserved at a special rate. The resort is at the end of Business Highway 54, south of Bagnall Dam. The new Highway 54 bypass to Camdenton offers a new approach to the resort.
Source: Robert Kallenbach, 573-884-2213