US - New research from Cornell University helps forage testing labs to more accurately determine the percentages of grass and legumes in forage, to help get cattle nutrition right.
Jerry Cherney, professor of agriculture at Cornell University, says commercial laboratories can only tell if samples are "mostly grass" or "mostly legume." This type of crude estimate just doesn't cut it.
Farmers need to know what percentage of their mixture is legume and what percentage is grass, so they can make sure their cattle are getting a healthy, balanced diet. To more accurately measure the composition of these forage mixtures, researchers have started using near infrared reflectance spectroscopy (NIRS).
Legume and grass molecules vibrate at different frequencies, emitting invisible energy known as infrared. Scientists can use instruments to measure specific near infrared wavelengths and determine the percentages of grass and legumes. But in order to provide accurate measurements, the instruments need to be calibrated.
"In the past, NIRS calibrations were typically instrument-specific. They only worked with the instrument used to develop the calibration," explains Cherney. So Cherney and his team of researchers worked to develop a single calibration that could be used with many different NIRS instruments.
The research team collected three years of alfalfa and grass samples to develop their calibration. They collected another year of samples to use later, to verify their calibration. After collecting the samples, they separated the alfalfa from the grass. Then they made over 500 samples that were mixtures with known percentages of alfalfa and grass to perform the calibrations.
Ultimately, Cherney was able to show that a single calibration can measure alfalfa and grass percentages across instruments. This is great news for farmers, and cattle, in the north east United States. Farmers now have more accurate information about what's in the food their cattle are eating. But some cattle may still be left guessing.
"While we're confident that the calibration should work for sites in the north eastern USA, we are not sure if it works for mid-western grown mixtures," Cherney explained. Calibrations for other parts of the country, like the Midwest, can be developed using the same process Cherney followed in the Northeast.
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