Has anyone found a discrepancy  between  the Wet 603 test and IR 601 Greater than 20% in the sugars of their hay?  I read studies that 20% was the range it could be off. I bought 15 bales of meadow grass  from feed store to supplement my high iron low sugar hay. I got the test back in 4 day using fasttrack. . Called they lab and said they calibrated every 20 to 30 samples, which is good. I have done both test on same hay and have found them to be very close. Even if I add the 20% it is <10%Just thinking after this last fiasco of buying 120 bales of low sugar hay that was really dirty and tested very high in iron. (The rinsed came back at 190 , better that 700!)
That I might just start buying only 25 to 30 bales from feed store so i am not stuck rinsing or soaking hay for they year.
Appreciate your feed back.
Lori, Abel, Bodie & Dusty


Redding, CA


 https://ecir.groups.io/g/CaseHistory/album?id=6053&p=Name,,,50,2,0,0 .


Lori asked: "Has anyone found a discrepancy  between  the Wet 603 test and IR 601 Greater than 20% in the sugars of their hay?"

This is my experience with hays available locally in my county from Northern California up near Mt. Shasta. I haven't seen a higher discrepancy than 20%, if you're talking about matched samples. IOW, if I sample 20 bales and submit that for both 601 and 603 analyses , I haven't seen more than a 20% increase of ESC in the 603 over the 601.  And if I submit the 603 before I submit the 601, then the 601 results are likely to be closer. 

But I don't think 20% off is "good" unless the 601 result is low enough to account for an increase of 20% in ESC. If the typical ESC result for California orchard grass is 7.5% using the 601 analysis, that means you're willing to accept that the wet chemistry ESC could be as high as 9%.  That may be fine for an IR horse in work that is compensated  IR, but for a sensitive horse with elevated insulin, hay with 9% ESC could very well be inappropriate without soaking.

There's another factor, too. If you have taken the NRCPlus class and calculate Mcal for your horse's weight and activity level, the 601 digestible energy (DE) is always lower  than the 603 DE even if the ESC results are really close. IOW, you can overfeed your horse using the DE calculation from a 601 analysis.

Cass, Sonoma Co., CA 2012
ECIR Group Moderator
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I sampled the same batch of hay using both 601 and 603, and the difference was huge.  It went from ESC+starch= 7.3 using 601 to 12.2 using 603.  Granted, it was not the same sample but I did core many of the same bales as I had for the 601 test.  It was quite disappointing to go from "yay! I don't have to soak hay anymore!" to "crap! I have to keep soaking hay..."

Heather F
June 2020

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