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How to Test Your Hay

Updated: Dec 30, 2023

Congratulations!!! You've decided to stop guessing about the primary constituent of your horse’s diet. By defining the strengths and weaknesses of your horse’s primary forage, it will become crystal clear what is necessary to compliment it. This is the most important step in designing the perfect diet for your horse. Very soon you can start gloating over the results.


I would assume that less than 1% of horse owners take a forage sample over the course of their equestrian careers. So, well done, you're at the top 1% of the entire horse owner pyramid! Perhaps you have come around to the necessity of forage testing due to the rising cost of hay, a recent diagnosis from your veterinarian, or you want to be sure that you're supplementing correctly. There are infinite reasons to get a hay test done, but the first time can be daunting. This article describes the process to you in three steps. A "How to Test Your Horse Hay" YouTube video can be found in this article as well if you prefer an audio-visual.


But first, let me lay out a few assumptions. This article covers the testing of hay bales (square or round). It does NOT cover fresh pasture sampling of live grasses. Secondly, I'm assuming that you are feeding horses, donkey and/or mules. I'm also going to assume that you have not done this before, so I will try to be very thorough.

Your Management Preferences + Strengths and Weaknesses of Your Hay = The Correct Feed/Supplement Diet Plan


The first step towards acquiring a forage analysis is the hardest, because it requires the greatest degree of “activation energy”. This step is also the most critical to get right, because the results are only as good as your sampling technique. You want the hay sampled to be a sound representation what your horse is actually going to be eating over the course of the next few months. If you are going to design an entire diet plan from the results, you want to be confident in your methods. This is especially critical when you are feeding horses with disease or at very high performance levels. Is that reported non-structural carbohydrate level an accurate representation of what your laminitic horse is eating today? Is that crude protein level an honest average of what your upper level sport horse is consuming during show season? Is that relative feed value worthy of making a large buying decision? Again, the results are only as good as your sampling technique.

It is also VERY important that you keep your sampling to bales that come from same species, year, and cutting number. DO NOT MIX SAMPLES FROM 1ST OR 2ND CUTTING! DO NOT CORE A STACK FROM THIS YEAR AND LAST YEAR AND MIX TOGETHER! YOU WILL ONLY CONFOUND THE RESULTS.

Gather Your Equipment

  1. Forage probe with punger

  2. Drill

  3. Electricity (outlet, generator or cordless drill batteries)

  4. Plastic grocery bag

  5. Quart sized zip lock bag or sample bag from lab kit

  6. Sampling form provided by the laboratory

  7. Black sharpie and pen

Sourcing a Forage Probe and Drill

It is absolutely critical that you source a hay coring device (aka forage probe). Handfuls of hay grabbed from the floor of the barn are worthless. There are many styles of forage probes, but my preferred device is commonly known as a Penn State forage probe- 18-24” in length. These probes attach to an electric drill and finely chop the hay as they bore into a bale.

There are three common ways to acquire a forage probe:

  1. Borrow one from your county’s extension office run by your state's land grand university. Your tax dollars are paying for this, and it's usually free. Simply Google "your county" + "your state" + "extension office" for contact information. A few progressive feed stores might do this as well.

  2. Contact your regional feed company representative to come sample for you. When I was a sales representative, I would often do the first coring and test for free.

  3. Purchase a probe for yourself. There are several places online to purchase a Penn State forage probe including Nasco or Best Harvest.

You will also need a hefty drill- the more powerful the better. I prefer a corded drill whenever possible (I’ll even bring a generator when there isn’t a power source at the stack), but a cordless drill is doable as well. Just make sure that you bring several extra charged batteries with you as coring hay bales drains drill batteries very quickly.

CORE 10-12 BALES (round or square)

No matter the size of your stack, whether it be 10 bales or 100 ton, I recommend taking 10-12 cores with your forage probe. Core into the short, square end of the bale, so that your probe crosses as many flakes as possible (*see image below). The amount of effort you have to exert on the drill and probe will vary with the species of forage and how tightly the grower packed the flakes with his/her baler. Coring bales is a bit of a workout, so don't be surprised if you break a sweat and wear good shoes. Be careful, because the tip of the forage probe can often get very hot.

The most important point to remember in this step is to be as unbiased as possible when choosing bales to core. Again, the result are only as good as your sampling technique. DO NOT consider color or consistency when choosing bales. You may use the very scientific, “close your eyes and point” technique. Sample bales that are high, low, and midway up the stack. Travel the length of the hay stack and core from as many areas as are safe to access. This will give you the best confidence in the results.

Core perpendicular to the flakes in the bale.

A plunger placed down the barrel of the coring device will push the hay sample into your bag.


Deposit each cored sample into a plastic grocery bag or gallon sized zip lock bag. Ten to twelve cores will just about fill up a gallon sized ziplock. Then, mix the finely chopped hay thoroughly for 2 minutes with your hand. The more you mix the merrier. From that mix, cup your hand and extract enough chopped hay to fill a quart size zip lock or the provided sample bag. Cupping your hand with your palm facing up will keep the very fine bits of hay from being left behind at the bottom of the bag. Label that quart sized zip lock bag with the type of forage, the cutting, a description of the field where it was cut, and the date that you sampled it. This is the sample that you will send to a lab.

Label Your Sample

  1. Type of forage (i.e. mixed meadow grass hay, alfalfa-grass mix, soybean hay)

  2. Cutting (i.e. 1st, 2nd, or 3rd)

  3. A description of the field or grower's name (EX: Cameron North Field)

  4. Date of Sampling


*Mixing the cored samples together thoroughly will ensure best results.

You can also watch this video of the same techniques on YouTube.



If you just want to know where to send the sample, know that Equi-Analytical, a division of Dairy One out of Ithaca, NY, is my preferred testing lab [CLICK HERE TO GO THERE]. For 99% of you, I will recommend the Trainer package #603. If you are interested in the details of WHY, that is below.

Laboratories vary in their testing methods, packages, and costs. As far as testing methods, there are basically two types: 1) near infrared spectroscopy (NIR) and 2) wet chemistry. In the simplest of terms, NIR machines shoot light waves at a hay sample and compare the light waves that bounce back to a standard. The NIR method is relatively quick and inexpensive. It will always be the cheaper package options on a lab form- typically between $20-$40. There is a good example in the image below. The analytical packages 600 and 601 are NIR. The second method of analyzing nutrient composition is wet chemistry. In essence, this is the extraction of nutrients out of solution- imagine the classic chemistry lab with lots of clear glass jars and tubes bubbling over. Wet chemistry is more expensive, but generally regarded as more accurate especially with mixed grass hay samples. This is especially true when you are hoping to understand the non-structural carbohydrate value of your hay. These packages are typically around $60-$80.

Most small, local labs will only offer NIR, so be sure to ask or consult their forms. Larger, regional or national laboratories have more expensive equipment and can do wet chemistry. Sometimes they will package NIR and wet chemistry together to optimize cost. For example, Trainer package #603 uses wet chemistry for protein, carb and fiber values but uses NIR for the minerals. This helps you balance cost with reliability. Local labs will sometimes send the sample onto their larger parent labs when wet chemistry is requested.

Most laboratories report nutrient results that best optimize for beef and dairy cattle. This is why I recommend using Equi-Analytical for newbies. They are unique in that they have packages that optimize results for horses. For example, they will report Digestible Energy in values we can translate to equine diets.

Forage labs also vary in their quality. You can learn more about how your local or regional lab rates at the National Forage Testing Association. They have a list of labs that are certified in NIRS and Wet Chem analysis of forages. Check out the list and other excellent resources on their website-



How you interpret the results will depend on your horse’s needs. If you have a fat, laminitic pony you will be looking for a very different forage than if you own a stable of race horses. It’s important to understand that there are no “GOOD” or “BAD” forage results for horses. There is only what is appropriate for your horse or herd. You can start learning about the key elements of a forage test result in an recent article titled "Relative Feed Value: The Most User Friendly Number for Feeding Horses."

Below are the results of a local, first cutting grass hay which makes up the majority of hay in my barn. My horses will be subsisting on this for about 6 months of winter, so it's critical that I understand it's strength and weaknesses in order to supplement appropriately and ensure that my horses look their best when show season comes around again.

If the numbers on this forage test look completely foreign to you, then you will want to seek the help of a nutritionist who is familiar with forages. It's important to understand the differences between As Fed and Dry Matter, how to estimate digestibility, and how the numbers interact with each other. Natalie is uniquely qualified to help you interpret your forage results due to her education and experience in the United States Forage Industry. She spent four years across three states testing nine different variables to affect the quality and non-structural carbohydrates values of horse hay. During her studies, she collaborated with forage growers, researchers and extension agents at multiple conferences and meetings around the US to better understand the industry. She has evaluated thousands of forage tests and helped hundreds of horse owners feel confident about their hay choices. Schedule a FREE 15 Minute Discovery Call to learn more.

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