Mississippi hay growers can make use of a new, portable forage tester to quickly determine “when is the best time to cut their hay and preserve quality,” says Rocky Lemus, Mississippi State University (MSU) Extension forage specialist.
The near-infrared reflectance spectroscopy (NIR) machine, made by the Italian company Dinamica Generale, measures moisture, fibers and crude protein levels. He bought the unit using $30,000 in grant funds and says crude protein data will help growers manage nutrients.
“A lot of producers are applying all fertilizer at once – or they’re not splitting their applications correctly. This information will help us show, based on crude protein, how much nitrogen isn’t there. And if they need to adjust or split nitrogen applications in a different way,” says Lemus.
The unit has been calibrated for use on Mississippi forage crops including annual ryegrass; wheat, rye and oat small grains; alfalfa; annual and perennial clover; bahiagrass; bermudagrass; tall fescue; and summer-annual crabgrass, teff and forage sorghums.
“We’re taking samples of different harvest dates on those crops and running them through the machine. We also use our machine in the lab to validate that data with wet chemistry. One of our goals is to be able to develop specific equations for predicting the quality of all of these forage crops,” he says.
People have been very skeptical of the accuracy of portable units, says Matt Dobberstein, a Dinamica Generale regional manager based in Hudson, WI. “That’s because those out years ago didn’t work the way they were supposed to. Nobody kept up with the calibrations. But we do calibrations constantly, so the systems are always upgraded every year.”
The past year and a half he’s worked with the University of Wisconsin to measure the new tester’s accuracy. In July, results of that research will be presented at the American Dairy Science Association annual meeting. Dobberstein says portable-unit accuracy matches that of commercial labs.
“We will also have relative feed value as one of our chemical parameters in the near future,” he says.
The portable unit will help hay growers see the value of forage testing, Lemus adds. “I usually try to emphasize to my producers that they need to balance quality and quantity of that yield. You have to be able to go in the field – especially in crops like bermudagrass that tend to lose forage quality quickly – and tell a producer, ‘You’re now at the prime of this forage’s quality. If you wait more than a week or so, you start losing quality.’
“It’s real-time information,” he points out. “Usually when you send a sample to the lab, it might take one or two weeks, depending on how busy the lab is, to get that sample back.”
The forage-analysis equipment can also give a cattle producer a more accurate assessment on when to graze a specific pasture based on the quality of the grass, Lemus says.
The grant was from the Mississippi Agricultural and Forestry Experiment Station, the MSU Extension Service and the department of plant and soil sciences.