Hay testing; NIR vs wet chemistry #nirwetchem

Terri Plake

Hi Everyone,

Mineral balancing for hay with the different lab methods:
My hay corer research finally led me today to a well established forage/soil/manure testing
lab in Lynden WA. They use wet chemistry method only. The lab owner said that although NIR
method has been calibrated, he said that the accuracy on an individual sample can be
compromised as compared to wet chemistry. Those of you who have done mineral balancing
using DairyOne analysis seems to work fine? Would the spread sheets;be different for wet
chemistry analyses? There is a large difference in price between the two methods. Is NIR
good enough for our purposes - especially if all the mineral balancing has been done using
analyses from this method? Can I use wet chemistry or should I send samples to DairyOne?
The lab loaned to me their nice corer to use.

Thank you all for all of your experience.
Terri, and Toby and Katie

Eleanor Kellon, VMD

I have to agree about the NIR. From what I can determine, NIR needs to
be calibrated for each type of sample (e.g. species of grass) and even
then samples from a different area with significantly different
compositions might throw it off.

Your safest bet is to use tests only when the lab has independent
certification for the specific tests. Some labs are certified for NIR
for major minerals only (there's universal agreement it can't be used
for trace minerals). I've yet to see a lab certified for NIR for
carbohydrate fractions (or wet chemistry for carbs either for that
matter but there are standardized testing methods). If you could find
out from the lab what the method is that they use for sugar and starch,
we can tell you if it's comparable to what Dairy One does.