How to Read (and Understand) a Hay Test

So you found some hay that your horse seems to like, and the supplier says that it’s good horse-quality hay. Great! But what does that really mean? If you ask, you’ll probably be told the protein content, which is nice to know. But is there more?  

Many hay growers do, in fact, test their product, so don’t be surprised if you’re given test results to review. Will you know what you’re looking at? In this blog, we’ll help you make sense of it! 

Why Hay Analysis Is Important

For most horses, hay makes up the majority of their diet.  A laboratory-conducted analysis provides insight into the actual nutritional content of the hay. That’s important stuff, as you create feeding and supplement plans for your horses based on their workload or age. 

But for a horse with health issues, such as food sensitivities, allergies, or special dietary needs due to metabolic dysfunction (such as IR, EMS, or Cushing's/PPID) - that information is life-changing! For example, if your horse is Insulin Resistant (IR), it’s crucial to know the sugar and starch levels in your hay. 

Can I Order A Hay Test?

Of course you can! Hay testing isn’t limited to farmers or commercial growers. In fact, if you buy hay in bulk, as many horse owners do, you probably purchase a number of bales from each of your supplier’s “cuttings”, or crops, throughout the growing season. 

The nutritional makeup of the hay you get can vary with each cutting and from field to field. . Weather and soil conditions during growing make a difference, as does the temperature at cutting and the amount of time between cutting and baling. Hay farming may be more stressful than horse ownership if that’s possible. There are tons of variables in hay production! 

So testing your hay is a good idea, especially if you’re feeding a horse with health issues. 

Choosing a Laboratory

While there are many commercial labs to choose from around the world, we recommend Equi-Analytical, a New York, USA laboratory. Equi-Analytical offers several testing packages. We generally direct customers to either the ‘Trainer’ or the ‘Equine Complete’ package.

Choosing Between the NIR or Wet-Chem Test

Some commercial testing labs offer a choice in testing methods. Near-Infrared Reflectance (NIR) spectroscopy bases its analysis on standard calibrations for common feed types. While these calibrations are the result of thousands of samples, bear in mind that NIR can only be used on a feed type for which it has been calibrated. And NIR results are only as accurate as the reference samples used in that calibration. 

Wet Chemistry (Wet-Chem) procedures are the more traditional testing method and can be applied to any sample type. We always suggest this method to clients, because it: 1) tests your actual hay sample (Wet-Chem methods are used for samples where no NIR calibrations exist and do not require any past tests or similar samples to create an analysis); 2) consistently provides more reliable and accurate results, and 3) is the gold standard for hay testing.

Wet-Chem testing is a bit more expensive than NIR, and takes two to three days to complete, as time proven methods are used to determine nutrient composition. 

Getting a Good Sample for Testing

 Watch this video to learn how to take a hay sample for testing. 

The Results Are In - Now What?

You’ll more than likely receive your hay test results by email. The collection of information, acronyms, and laboratory terminology might make your head spin.  Let’s go over the components that really matter. 

Moisture vs Dry Matter

Moisture is the percent of water in the hay sample, and the dry matter is everything else. The general rule of thumb is to look for moisture levels under 15%, though this will vary slightly depending on where you live.

‘As Sampled’ Vs ‘Dry Matter’ Basis

‘As Sampled’ refers to the nutrient results for the entire sample, including both moisture and dry matter. Another way to think of this, is “As Sampled’ is what you are actually feeding in its entirety. ‘Dry Matter’ is the nutrient results for just the dry matter portion (no water) of the sample.

Crude Protein (CP)

Crude protein is the total protein in the sample. For the average horse in moderate work, 10-14% protein (as sampled) is generally recommended. 

Neutral Detergent Fiber (NDF) vs Acid Detergent Fiber (ADF)

Neutral Detergent Fiber (NDF) measures hemicellulose, cellulose, and lignin (the fibrous bulk of the forage). NDF should generally be between 40-50%. As a rule of thumb, it’s commonly said that the higher the NDF, the less palatable the hay. Acid Detergent Fiber (ADF) measures cellulose and lignin only. ADF should generally be between 30-40%. The lower the ADF, the more digestible the feed.

Crude Fiber (CF)

Crude Fiber is an old method of fiber analysis, and not the most accurate measurement for fiber, particularly for forages, so we don’t use this figure when looking at hay tests.

ESC + Starch

** The most important for IR/EMS Horses **

If you have an IR horse, this is the number you’ve been waiting for! 

When looking at the carbs on a hay test, the first thing to look at is the Ethanol Soluble Carbohydrates (ESC) and Starch. If you have a horse with metabolic challenges like Insulin Resistance or Equine Metabolic Syndrome, add the measure of ESC to the measure of Starch. These are the two carbohydrates that cause glucose spikes and increased insulin levels. 

“Good” is a total of less than 10%. 

ESC + Starch < 10%

Remember that generally, the higher the starch, the higher the energy content in the hay. But starch converts 100% to glucose, so for horses with metabolic issues (IR/EMS), the lower the starch, the better.

You may have heard about another measure, Non-structural Carbohydrates (NSC). This is an old term, and was used to describe the total of Water Soluble Carbohydrates (WSC) and Starch. As with all health discussions, there are conflicting arguments as to which numbers should be used to analyze hay for metabolic horses. 

Water Soluble Carbohydrates (WSC) are the carbohydrates solubilized and extracted in water. WSCs include the ESCs. The difference between the ESCs and NSCs is mostly fructans, which are not often considered to affect insulin levels in EMS/IR horses.

Digestible Energy (DE)

Digestible Energy is the energy that is digested and absorbed. The higher the energy output of the horse, the higher the DE should be. Feeds with higher DE are often associated with horses becoming “hot.”

Relative Feed Value (RFV)

Relative Feed Value is a way of measuring forages based on digestibility and intake potential. An average RFV is 100. The higher the RFV, the better the quality. 

Nitrates (NO3)

Nitrates can become a problem when fed in high amounts. **This is not included in hay analysis packages but is a great add-on for the additional cost.**

Conclusion

The forage your horse eats provides a multitude of nutrients. As you can see, a hay test can give you much, much, much more information about the quality of the forage you’re buying and feeding. 

In this blog, we attempted to cover the key metrics included in your hay test analysis, but we didn’t cover all the information which also includes measures for the various minerals included in the hay. For help understanding these values, we recommend consulting a qualified equine nutritionist. You can also check out the Calculator for Nutrient Requirements of Horses put out by the National Research Council. 

Hopefully, this blog gives you information you can use to better understand what you’re feeding and how it supports your horse’s overall health and nutritional needs. Especially if you’re dealing with IR, Cushing's, PPID, or other Equine Metabolic Syndrome horses, this level of detail is crucial.