How to Calculate ESC and WSC?


I'm sure it's posted somewhere, but what is the formula for calculating ESC and WSC? For some reason I remember seeing that you can't use the number straight from the hay analysis. Thank you for your patience! 
June 2020 Berlin, Massachusetts,,,20,2,0,0

Lavinia Fiscaletti

Hi Suzanna,

ESC, WSC and starch should be listed right on the analysis if it was done by Equi-Analytical/Dairy One.You want to use the As Fed numbers.

Lavinia, George Too, Calvin (PPID) and Dinky (PPID/IR)
Nappi, George and Dante Over the Bridge
Jan 05, RI
Moderator ECIR

Sherry Morse

Hi Suzanna,

Both of these measurements are included in most hay analysis and that includes yours - in the section under carbohydrates the 2nd line is ethanol soluble CHO (ESC- sugar) and the 3rd line is Water Soluble CHO (WSC - Sugar). 


Are you wanting to know if your hay is safe for your horse to eat? What is important is ESC (ethanol soluble sugars) and Starch. Combine the % numbers of the two and they should be below 10% or ideally even lower. I took a look at the hay test you have in your case history. The ESC= 10.2 and the starch = 2.8. The combination is 13, too high for it to be safe to feed without soaking to an IR horse.

Perhaps you are looking for a new hay? As long as you have the numbers for ESC and Starch you can ignore NSC and WSC. 
Bonnie Snodgrass 07-2016

ECIR Group Primary Response 

White Cloud, Michigan, USA

Mouse Case History, Photo Album


Thanks Bonnie! 
Yes, that was my question. I wasn't sure if I add the WSC and ESC together. It's ESC and starch.  
The new crop of hay has lower percentages, which puts it just under 10% thankfully. Soaking hay in sub zero temps wasn't something I looked forward to. On those days I know I can safely skip soaking.
We bale our own hay. I wonder if there is any info on crop management and how it affects sugar levels. 
Thanks again everyone for the help! 
June 2020 Berlin, Massachusetts,,,20,2,0,0

Kirsten Rasmussen

Hi Suzanna, there is some information on crop management in the messages here and in Horsekeeping.  My take is that ensuring grasses are not stressed by drought or lack/excess of nutrients (ie, have been appropriately fertilized based on soil analysis) are critical.  As well as various factors when you cut the grass, detailed here:

Kirsten and Shaku (IR) - 2019
Kitimat, BC, Canada
ECIR Group Moderator
Shaku's Case History  
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