In order to formulate a custom supplement, we will need an analysis of your hay and/or pasture. This is not hard to do. You gather the sample yourself, package it in a Ziploc bag, and send it to a forage testing laboratory. (If analyzing your hay is not practical, if your barn gets hay in very frequently for example, we can still design a supplement to target the most common deficiencies for your horse in your area.)
The lab's analysis will be only as good as the sample that you send to the lab; the sample needs to be representative of the entire lot of hay that you will be feeding. Choose the hay bales from which you sample at random; do not purposefully choose some bales over others.
The best way to sample hay is with a hay/forage probe or coring device. One can be homemade from an old golf club. Directions for making one may be obtained by contacting Litchfield Analytical Services.
There are commercially available hand coring devices and probes that connect to an electric drill. Prices range from about $35 on up.
Three examples are:
For a more extensive list of hay probes, see Forage Sampling and Sampling Equipment from Iowa State University Extension.
For more information on how to take an accurate sample, please see:
For hay testing, we recommend Dairy One Forage Laboratory in Ithaca, NY. Choose either F-321 with M-329 ($24 total) under NIR packages or #10 under Wet Chemistry.
Dairy One's sample submission form can be downloaded here.
You may also be able to find a laboratory closer to you by contacting your local agricultural extension office or through the National Forage Testing Association.
We recommend that the analysis include information similar to that found in Dairy One's F-321 with M-329 or Wet Chemistry #10 (DM, CP, ADF, NDF, NFC, DE, Ca, P, Mg, K, Na, Fe, Zn, Cu, Mn, and Mo).
If your horse has been diagnosed with insulin resistance, you may want to include sugar and starch (Dairy One's 254 and 34) in your analysis, if those are not part of the package that the lab offers.