Feeding a quality forage should be the basis of every feeding program. Given the forage portion will account for the large majority of nutrient intake for your horse, isn’t it important to understand what is in that forage?

By knowing what is needed to fill in the gaps, you can take the guesswork out of feeding grains, commercial feeds, and supplements to your horse.

Obtaining and knowing how to read a hay analysis is a skill that can help you create the optimal starting point for your horse’s nutrition program.

Taking a Hay Sample

Forage Probe for Taking a Hay Sample

A forage probe is the best way to obtain a hay sample to send for analysis.

The first step in obtaining a hay sample result is getting a representative sample of your hay.  This is best done using a forage probe, which is just one example of the many probes available on the market.

For many horse owners, purchasing a forage probe may not be practical. Local feed stores, agriculture cooperative or government agency will have forage probes on hand that can be borrowed.

Ideally, 10-20 individual bales should be sampled to get a representative sample. Smaller sample sizes as few as 2 to 5 can be done as well.

It is important to note though that the fewer the samples, the more likely you are to sample an outlier that may not be representative of the batch. This is particularly important in alfalfa/grass blends as the amount of each can vary widely between bales.

Failing any of the above options for obtaining a forage probe, it is possible to take grab samples of forages with a sturdy pair of scissors. Open the bales gently (you do not want to lose the leaf matter in your sample, as horses will preferentially eat this and they are the most likely to fall out of your sample).

Firmly grab a sample out of the slab and use the scissors to cut each side of the hay, so you are left with a handful of hay sample. Drop the hay sample in your ziplock bag and repeat 9 more times on different bales.

Most labs only require about 100 grams of sample for a full analysis, but you should obtain more than that, but do not exceed 500 grams (1 lbs) of sample.

Selecting Your Lab for Analysis

With your hay sample secured, now it is time to send the sample off to a certified laboratory. Most forage laboratories will offer an ‘equine’ sample analysis. This is no different in terms of the analysis they do, it is just a tailored report for horse owners.

You’re going to the trouble of taking the sample, now is not the time to cheap out. Ensure you get a complete trace mineral analysis by wet chemistry done on your hay sample.  For most labs, this will be an extra checkbox and of course charge. A hay sample with full analysis with trace minerals by wet chemistry should not cost more than $50.

Unless, you totally want to ‘geek’ out and get a full ruminant analysis done, which will include NDF digestibilities – that will cost more. I will save that for another article. An example submission form from SGS laboratories in Guelph, ON is shown below. The submission form must be included with your sample.

Sample Hay Analysis Submission Form

Below are links to some certified forage laboratories and their respective feed submission forms:

Quebec

Valacta Ste-Anne-de-Bellevue, QC
Agri-Analyse Lennoxville, QC

Newfoundland

Fisheries and Land Resources St. John’s, NFL

Prince Edward Island

PEI Analytical Laboratories Charlottetown, PEI F2 Forage Package (Non-Silage)

Western Canada

Central Testing Laboratory Ltd. Winnipeg, MB 10FF Equine Forage Pack
Parkland Laboratories Chilliwack, BC FP 3: FP 2 plus minerals
Fraser Analytical Abbotsford, BC
Nutrilytical Calgary, AB 604 Equine Complete

Kentucky

Kentucky Department of Agriculture Frankfort, KY
Waters Agricultural Labs, Inc. Owensboro, KY Feed Test 5 + Mineral Analysis

New York

Equi-Analytical Ithaca, NY 604 – Equine Complete
Batavia Forage Lab Batavia, NY A2 – NIR 2

Pennsylvania

Cumberland Valley Analytical Services Waynesboro, PA

Texas

Circle H Headquarters LLC. Dalhart, TX NIR 2

California

Southern Counties Forage Lab Shafter, CA NIR 2
Analytical Feed and Food Laboratory Visalia, CA Forage Test “B” + Trace Mineral Test

The Next Step: Reading the Analysis

You’ve patiently waited for your hay sample results, now it’s time to go through an hay analysis report and decipher what they all mean for your horse’s nutrition.

Presented here is a report generated from a sample of first cut, Ontario hay. This particular report is from SGS Laboratories in Guelph, Ontario and the analysis chosen is called “Equine Complete,” which tests for nutrients significant to horses.

Sample Forage Analysis Report for Horses

Dry Matter % and Moisture %

Hay is just dried grass, and grass contains a lot of water. Hay will have some amount of moisture in it- typically around 10%. The “dryness” of a hay is measured in percent dry matter, so if you have hay with 90% dry matter, the moisture or water content will be 10%.

When you read the values on your hay analysis, there are typically values on both an “As is/As sampled” and a “Dry basis.” Whichever you choose to look at, you want to be consistent. Often, animal nutritionists use the values on a Dry matter basis due to the variation in the moisture content of feedstuffs. We will use the Dry matter values in this guide.

Protein %

Crude Protein %

Protein % is often also referred to as Crude Protein %, and it is an estimate of the total protein content of the hay based on the nitrogen content. Legume hays, such as alfalfa, will contain higher amounts of protein (15-20%) than grass hays (8-14%) like timothy and orchard grass.

The average, mature horse can do well on a hay with 8 – 10% crude protein, whereas growing horses or broodmares in late gestation will require hay that is 12-18%. Hay with less than 8% crude protein may not be sufficient to reach requirements for a mature horse and supplemental protein may need to be added to the diet

This particular hay has 12.21% protein, so it would be on the high side for a horse at maintenance and not enough for a lactating mare or young growing foal.

Remember, excess protein in the diet requires extra energy for the horse to metabolize, and is excreted in urine as urea which can result in a strong ammonia smell. Ammonia is a strong irritant to the respiratory tract and it should be every horse owner’s goal to minimize ammonia levels in barns.

Soluble Protein %

Soluble Protein %, or SP %, is the soluble fraction of the protein that is readily available to the animal. It contains small amino acid chains and non-protein nitrogen (NPN).  NPN is of limited to no value to the horse. In dry hay, SP% should be between 20-35% of the total CP. The soluble protein value is used more for ruminants and in particular for ensiled feeds, than for evaluation in horse diets.

ADF-CP%/ADP/ADIP – Acid Detergent Insoluble Protein

This is the amount of protein that is bound to the ADF or insoluble fiber fraction of the hay. For a more accurate assessment of protein available for utilization by the horse, subtract this value from the crude protein. 12.21-2.21 = 10.00%.  In other words, 18.1% of the total crude protein will not be digested by the horse.

This is a close representation of ‘available protein’. To get a more accurate assessment, we would also have to subtract the NPN fraction of the soluble protein as well, but that is well beyond the scope of most nutrition balancing programs.

NDF-CP%/NDP/NDIP – Neutral Detergent Insoluble Protein

As with ADIP, this is the fraction of protein bound to the NDF fraction.

Note: ADIP & NDIP are not given on most common equine forage samples as they are not utilized in most ration balancing. Although the values are important, they are not a key focus of most equine ration formulation.

Plant Carbohydrates

Plant Carbohydrates in the Horse Diet

Acid Detergent Fiber (ADF) %

The ADF of a hay is the portion comprised of cellulose and lignin. It gives an estimate of how much energy the horse can derive from the hay.

As lignin content increases, digestibility of cellulose decreases, which lowers the potential energy that is available to the horse. So, a low value means that cellulose is more available to be digested.  The DE (digestible energy) value for horses is calculated based on the amount of ADF.

30-40% ADF is a good range for horses and values above 45% may be too fibrous or indigestible for the horse to acquire adequate energy from. This is the common cause of ‘hay belly’ – feeding hay too high in ADF.

In this case, the ADF is 40.3%, which is a little bit on the higher side, so it may not deliver the nutrients needed for a high-performance horse or a mare at peak lactation but is a sound choice for horses that are at maintenance or doing light work.

Neutral Detergent Fiber (NDF) %

NDF is a measure of insoluble fiber and includes all of the cell wall carbohydrates- lignin, cellulose, and hemicellulose. Lignin is indigestible, but hemicellulose and cellulose can be partially digested by microorganisms in the hindgut.

NDF can be used to estimate forage intake- the higher the NDF, the less a horse will eat. NDF levels between 40-60% are suitable for horses, but when hays reach NDF values over 65%, it may limit intake and therefore the horse may not be able to obtain sufficient energy for maintenance.

This hay has an NDF value of 56.6%, which is fairly high. It would be good hay to feed to an easy-keeper, where the goal is to make sure the horse is consuming enough roughage to keep the gut moving, but not to provide excess calories.

Lignin %

Lignin is the indigestible component of plant cell walls. This means that even the fiber-digesting hindgut microorganisms are unable to break it down to be used as energy. The lignin in this hay is 7.8%.

Fat

Fat % or Ether Extract (EE)

Hay contains fat in the form of fatty acids. Typically, mixed grass hays contain 1 – 3 % fat. The laboratory process of extracting fat from hay, ether extraction, removes other plant residues (waxes and pigments) that are not ‘true fat’, so it is reported as crude fat. Generally, the true fat content of dry hay is 80-90% of the reported value.

In this case, fat (%) is 1.48%, but the ‘true fat’ content would be 1.33% (90% of 1.48). Most laboratories will not report ‘true fat’ on an equine analysis, but will on a ruminant forage sample.

Sugars and Starches

Balancing sugars and starch in your horse’s diet is a crucial step on the journey towards developing a balanced diet. Most hay analyses for horses will include WSC, ESC and starch values; it is important to double-check that these will be included in your forage sample.

Water Soluble Carbohydrates (WSC) %

WSC includes simple sugars, disaccharides, oligosaccharides, some polysaccharides, and fructans and pectins – forms of sugar stored in plants.

Ethanol Soluble Carbohydrates (ESC) %

ESC is a portion of WSC and includes mainly monosaccharides, disaccharides, and oligosaccharides (saccharide is just a generic term that could include the sugars fructose or glucose) that are broken down and digested in the small intestine.

This number is often important when looking at diets for horses with insulin resistance and/or chronic laminitis, as it is what will contribute to the glycemic load.

Starch %

Starch is a polysaccharide (long-chain polymer of glucose molecules) that is present in hay, generally at very low levels. It is digested in the small intestine and will also contribute to the glycemic load.

Forages that are very mature can have a lot of seeds and that can significantly increase the starch level of the forage. 

Feeding large amounts of starch can cause it to escape digestion and rapidly ferment in the cecum, which can increase lactic acid production and cause dysbiosis.

Non-Structural Carbohydrates (NSC) %

Non-structural carbohydrates form the fraction of the hay that is made up of starches and sugars.

The NSC value is a calculated value that is useful for evaluating the diets of horses that are sensitive to large amounts of NSC in their diet. These include horses with metabolic problems such as insulin resistance, Equine Metabolic Syndrome or Polysaccharide Storage Myopathy.

Horses like these require a ration that is limited in starch and sugar and should be fed hay with an NSC concentration below 10%. NSC can be calculated as ESC + Starch.

NSC  represents one of the most misunderstood values in horse nutrition. This is due to the fact that most laboratories report NSC as WSC + Starch, which is used in ruminant nutrition.

The difference between WSC and ESC (in this case 2.47%) represents fructans and pectins in the hay. These are not digestible in the small intestine and do not contribute directly to glycemic load. However, they are rapidly fermented in the hindgut.

NSC calculated for the purposes of horse nutrition is: ESC + Starch = NSC.

Minerals

All of the minerals that are reported on a hay analysis are essential nutrients that are necessary for overall health and must be available in the diet in adequate quantities to reach daily requirements. Some ratios of these minerals are particularly important to note due to their relationship with other minerals.

Ash %

The ash content of a forage is just what you might think it is. When the hay sample is burned at very high temperature, what is left is the ash %, which is a gross measure of all the minerals present in the hay.

Sodium %

Hay contains very small amounts of sodium. According to the NRC, 2.4% sodium is the maximum tolerable intake, and this hay contains only 0.09%. Access to free choice loose salt and fresh water should be available to horses, at all times, so that horses can attain their requirements.

Iron (ppm)

Most forages are naturally high in iron, and this hay contains 255.69 ppm (mg/kg) of it. The max tolerable limit for iron is 500 ppm.

Extremely high iron can interfere with the absorption of other minerals like copper and zinc, and so it should be balanced accordingly with a proper mineral and vitamin premix.

Ca:P Ratio

Calcium and phosphorus are the main structural components that make up bones and teeth. The ideal ratio of calcium to phosphorus is >1.5:1 & <4:1, which means that there needs to be more calcium than phosphorus in hay to maintain this ratio.

The Ca:P ratio of this hay is 2.89, meaning that there is almost 3 times as much calcium as phosphorus, making this hay balanced in terms of calcium and phosphorus. Ratios are important, but total intake needs to be considered as well to ensure adequate intake of each nutrient.

In this case, the hay is 0.29% P. At an intake of 10 kg of hay per day, the horse would be consuming 29 grams of P, which would be more than adequate for most class of horses.

Zn:Cu Ratio

Zinc and copper have crucial roles in the functioning of many enzyme pathways and in protein synthesis. Two very important proteins that zinc and copper help synthesize are keratin and collagen, which make up hoof and hair tissue.

The Zinc:Copper ratio is ideally at 4-3:1. This hay is at 7.15, so more copper will need to be supplemented in order to reach an appropriate Zn:Cu ratio.

Energy

Total Digestible Nutrients (TDN)

Today, TDN is rarely used in equine nutrition.  It is used to assess the total digestibility of the forage.

Digestible Energy (DE) (Mcal/kg)

Digestible energy is a measure of calories that are in the hay, and therefore a hay’s energy content. It is most commonly expressed as Mcal/kg, or megacalories per kilogram.

Often times, the DE value will show up on an equine hay analysis as “Horse DE,” depending on the lab analyzing the sample. This is because the DE values of forages for horses are around 15% lower than that of cattle, since horses utilize fiber less efficiently than cattle.

This hay contains 2.08 Mcal/kg hay. A 500 kg horse, at maintenance, requires an average of 16.7 Mcal of DE daily (1). A horse consuming 2% of its bodyweight of this hay (10 kg) would then receive 20.8 Mcal per day, which exceeds this horse’s daily requirement. It would be expected that this horse would gain weight if given this hay ad lib (free choice access).

Digestible Energy is a crude measure of energy. It is up to each individual horse owner to monitor the body condition of their horse/s to determine if more or fewer calories are needed.

 

After reading this article, we hope that you have gained a better understanding of how to better approach reading your hay analysis. For a detailed review of your hay analysis and more advice on equine nutrition, contact Mad Barn.

References

  1. National Research Council. Nutrient requirements for horses, National Academy Press, Washington, D.C., USA, 2007