Forage testing equipment, methods and calibrations can vary from lab to lab. That means results can vary, too.
“Variation between labs doesn’t necessarily mean that one lab is right and the other is wrong,” says Chris Dschaak, dairy nutritionist with Mycogen Seeds. “But it is important to be aware of the potential for differences and to stick with one source of lab data when making ration decisions.”
As an example, Mycogen Seeds recently sent samples from the same brown midrib (BMR) corn silage pile to five different labs and found that dry matter readings varied from 27.7 percent to 31.2 percent, and Neutral Detergent Fiber (NDF) content ranged from 46.6 percent to 58.4 percent.
Dairy producers should establish a relationship with one lab to ensure consistent results, Dschaak advises. “Seek the advice of your herd nutritionist to identify a lab that meets your needs,” he says.
Dschaak suggests asking these questions before selecting a lab:
- Is the lab certified by the National Forage Testing Association (NFTA)?
- Does the lab do its own wet chemistry testing to develop near infrared reflectance spectroscopy (NIRS) calibration equations?
- How frequently does the lab calibrate its NIRS equipment and monitor accuracy of calculations?
- How long does it take to get results?
- What are the lab’s quality-control procedures?
Regardless of the lab, Dschaak stresses the importance of ongoing communication.
“If you see something on a report that you don’t understand, ask your nutritionist or lab representative to explain it,” he says.