In part 1 of this series, we discussed characteristics and nutritive values of different types of forages along with factors that influence forage quality. In this article, we will explore how to test your forage, how to interpret the results, and some practical guidelines for hay management.
Hay Testing
As mentioned in our previous issue, forage quality cannot be determined reliably by species alone. How then can horse owners evaluate the nutritional value of hay? The answer is forage testing. A forage analysis provides an objective assessment of the nutrient composition of a specific lot of hay and can help horse owners make informed feeding decisions. For most horse owners, the cost of a forage analysis is small relative to the cost of hay and concentrate feeds and may help prevent unnecessary supplementation.
A forage analysis is only as accurate as the sample submitted to the laboratory. For this reason, proper sampling techniques are critical. Ideally, hay should be sampled using a forage probe designed to collect a core sample from the interior of the bale. Samples should be collected from multiple bales within a single lot of hay, as nutrient composition can vary even within the same cutting. Most recommendations suggest collecting core samples from at least 10 to 20 bales and combining those cores into a single composite sample for analysis. Sampling from the center of the bale provides a more representative sample than collecting hay by hand from the outside, where weathering and handling may have altered the forage.
A “lot” refers to hay harvested from the same field, cutting, and management conditions. Hay from different fields, cuttings, or suppliers should generally be sampled separately, as nutrient composition may differ substantially among lots.
Once collected, samples can be submitted to a forage testing laboratory for analysis, such as through your local Extension office or private labs like DairyOne, or Equi-Analytical. Many laboratories offer packages specifically designed for horse owners and provide information on moisture, crude protein, fiber concentrations, nonstructural carbohydrates, minerals, and digestible energy.
Interpreting Hay Tests
While forage reports can appear intimidating at first glance, a few key values provide much of the information needed to evaluate hay quality and determine whether additional supplementation may be necessary (Martinson, 2021).
Moisture is a critical value when evaluating a forage test. Ideally, hay moisture should fall between approximately 10 and 20%. Hay that is excessively dry may experience greater leaf loss during handling, while hay baled at excessive moisture levels is at greater risk of mold development, heating, and in extreme cases, spontaneous combustion. Moisture also affects calculations associated with nutrient intake and ration formulation. For this reason, forage nutrients are typically reported on a dry matter basis, meaning the water has been removed from the calculation. Reporting nutrients on a dry matter basis allows for more accurate comparisons among different forages and feeds.
Crude protein (CP) represents the total nitrogen content of the forage and serves as an estimate of protein concentration. For many mature horses at maintenance, forage containing approximately 10–12% crude protein can provide adequate protein when consumed in sufficient quantities (Martinson, 2021). However, growing horses, lactating mares, performance horses, and other horses with elevated nutrient requirements may require greater protein intake or supplemental protein sources.
Neutral detergent fiber (NDF) and acid detergent fiber (ADF) are measures of the structural fiber within forage. Both generally increase as plants mature. NDF represents the total cell wall fraction of the plant and is associated with voluntary intake and palatability. As NDF concentrations increase, horses may consume less forage. For horse hay, NDF values between approximately 40 and 65% are generally considered acceptable (Martinson, 2021). ADF represents the less digestible fiber components of the plant and is closely associated with digestibility and energy availability. In general, ADF values between 30 and 45% are considered desirable for many horse hays (Martinson, 2021). Horses with lower energy requirements may benefit from forage on the higher end of these ranges, while growing, lactating, or working horses may benefit from forage with lower fiber concentrations and greater digestibility.
Nonstructural carbohydrates (NSC) include sugars and starches that are readily digested by the horse. NSC concentrations are particularly important when feeding horses affected by metabolic disorders such as equine metabolic syndrome, insulin dysregulation, or a history of laminitis. While there is no single ideal NSC concentration for all horses, many nutritionists recommend forage containing less than 10–12% NSC for horses requiring dietary carbohydrate restriction (Martinson, 2021).
When low-NSC forage is unavailable, management strategies may help reduce dietary carbohydrate intake. Research has demonstrated that soaking hay in water prior to feeding can reduce water-soluble carbohydrate concentrations, although the degree of reduction varies depending on forage characteristics and soaking conditions (Wassel, 2017). While soaking may be a useful management tool for some metabolically sensitive horses, it should not be viewed as a substitute for forage testing.
Although no single value tells the entire story, understanding these measurements allows horse owners to move beyond marketing claims and evaluate forage quality objectively. Ultimately, forage analysis provides a far more accurate assessment of hay quality than species, appearance, color, smell, or other visual characteristics alone.
Evaluating Hay Without a Forage Test
Although visual evaluation cannot replace a laboratory forage analysis, it can help identify obvious quality concerns when purchasing hay. Consider the following questions:
- Are there any obvious problems?
Inspect hay for excessive weeds, foreign material, mold, dust, moisture damage, or signs of heating. Hay should be free of visible mold, have minimal dust, and should not feel damp or unusually warm. These issues may reduce palatability and, in some cases, pose health risks to horses. - Does the hay appear leafy or stemmy?
Leafy hay generally indicates a less mature forage, while coarse stems and abundant seedheads often indicate greater maturity. As forage matures, fiber concentrations increase and digestibility generally declines. - Are there excessive seedheads present?
Seedheads suggest the forage was harvested at a more advanced stage of maturity. While not necessarily undesirable for every horse, mature forage often contains greater fiber concentrations and lower digestibility than younger forage. - How does the hay smell?
Good-quality hay typically has a fresh, pleasant forage aroma. Musty, sour, or moldy odors may indicate spoilage, moisture damage, or improper storage conditions. - What color is the hay?
Color is often one of the first characteristics horse owners notice, but it should not be overemphasized. While green hay is commonly perceived as desirable, color alone does not determine nutrient value. Sun exposure, curing conditions, and storage practices can influence color without substantially affecting feeding quality.
Even when hay passes each of these visual assessments, appearance alone cannot accurately predict nutrient composition. Two hay lots that look nearly identical may differ substantially in protein, energy, fiber, or nonstructural carbohydrate concentrations. Whenever possible, forage testing remains the most reliable method for evaluating hay quality.
Making Practical Hay Decisions
By this point, one conclusion should be clear: selecting hay is about much more than choosing a species. While species influences nutrient composition, forage quality is ultimately determined by a combination of maturity, environmental conditions, harvest management, storage practices, and nutrient composition. Horse owners can use several practical strategies to make more informed forage decisions.
- Whenever possible, test your hay. A forage analysis remains the only reliable way to determine nutrient composition. Forage testing is relatively inexpensive and is available through numerous commercial and university laboratories. A forage analysis can provide valuable information regarding crude protein, fiber, energy, mineral concentrations, and nonstructural carbohydrates.
- Match forage quality to the needs of the horse. Growing horses, lactating mares, and performance horses typically require higher-quality forage than mature horses at maintenance. Conversely, lower-quality forage may be entirely appropriate for easy keepers or horses with lower energy requirements.
- Feed hay by weight rather than volume. Flake size and bale density vary considerably, meaning that two flakes may contain substantially different amounts of forage. Using a scale provides a much more accurate assessment of daily forage intake.
- Use forage that is consistently available, affordable, and appropriate for your management situation. In many cases, the “best” hay is not the species with the highest nutrient concentrations but rather the forage that reliably meets the needs of the horse while fitting within the owner’s budget and local availability.
Calculating Hay Needs
Selecting high-quality hay is only part of the equation. Horse owners must also determine how much hay will be needed to meet their horses’ nutritional requirements throughout the year.
Current recommendations suggest that horses consume a minimum of 1.5 to 2.0% of their body weight in forage dry matter each day, although some horses may consume more depending on age, physiological status, workload, body condition, and management conditions (NRC, 2006). For a 1,000-pound horse, this recommendation equates to approximately 15 to 20 pounds of dry matter in forage daily. Since hay is not 100% dry matter, horses consume slightly more (usually 17-22 pounds of hay) in order to meet their dry matter requirements. In certain situations, such as medically supervised weight-loss programs for obese horses, forage intake may be restricted to approximately 1.0% of body weight; however, such restriction should be implemented under the guidance of a veterinarian or qualified equine nutritionist to ensure nutrient requirements continue to be met (Phillips, 2019). At the other end of the spectrum, horses with greater nutritional demands or unrestricted access to forage may consume considerably more. Total dry matter intake from all feeds is commonly reported to range from approximately 2.0 to 2.5% of body weight per day, although intake may approach 3.0 to 3.5% of body weight under certain circumstances (Liburt, 2026).
Feeding less than recommended forage amounts may increase the risk of digestive disturbances, gastric ulcers, stereotypic behaviors, and other health concerns associated with restricted forage intake (Ermers et al., 2023).
Using the forage intake guidelines discussed previously, horse owners can estimate seasonal hay needs by multiplying daily forage consumption by the number of horses being fed and the expected feeding period. For example, a single 1,000-pound horse consuming approximately 20 pounds of hay daily would require about 1,800 pounds of hay during a 90-day winter feeding period.
However, the amount of hay purchased is not necessarily the amount of hay consumed. Hay losses occur during storage, handling, and feeding. Depending on storage conditions and feeding methods, hay waste may range from less than 10% to more than 40%. Feeding hay in a feeder, using slow-feed systems, and protecting hay from weather exposure can substantially reduce losses (Martinson et al., 2012).
As an example, consider a farm with six mature horses averaging 1,000 pounds each. If each horse consumes approximately 20 pounds of hay daily, the group would require about 120 pounds of hay each day. Over a 90-day feeding period, total forage needs would be approximately 10,800 pounds. Assuming 20% feeding and storage losses, the farm would need approximately 12,960 pounds of hay available to meet winter feeding demands.
These calculations can help horse owners estimate annual hay needs, identify potential forage shortages, and budget for hay purchases before winter feeding begins. While actual intake will vary depending on pasture availability, horse size, activity level, and environmental conditions, estimating hay needs in advance can help prevent unexpected forage shortages and rising feed costs.
Horse owners seeking a more detailed approach to hay inventory planning may benefit from the Hay Inventory and Purchasing Calculator for Horse Owners developed by Stewart and Wassel (2024), which incorporates horse numbers, body weight, feeding duration, bale weights, and anticipated hay losses into the calculation process:
How Do You Know if your Forage is Working?
Ultimately, the goal of any feeding program is to meet the horse’s nutrient requirements while maintaining appropriate body condition. Unfortunately, this is not always easy to determine by simply looking at a horse or evaluating the feed being offered.
Energy requirements can often be assessed by monitoring body condition over time. Horses that consistently lose weight may not be receiving adequate calories, while horses that continue to gain weight may be consuming more energy than they require. Because changes in body condition occur gradually, several weeks to several months may be required before the effects of a feeding program become apparent.
Body condition scoring is one of the most important skills horse owners can develop. The Henneke Body Condition Scoring System evaluates fat deposition at six locations on the horse’s body and assigns a score from 1 (poor) to 9 (extremely fat) (Henneke et al., 1983). Most mature horses perform well at a body condition score between 4 and 6.
Body condition scoring provides valuable feedback regarding whether a feeding program meets energy requirements. While forage analysis can help predict nutrient intake, body condition scoring helps determine whether those predictions align with what is occurring in the horse. More information on body condition scoring can be found in this Equine Exchange video and our flow chart tool.
Forage selection should be viewed as part of a larger nutritional management strategy. The “best” hay is not necessarily the most popular species or the forage with the highest nutrient concentrations. Instead, the best hay is the forage that consistently meets the nutritional needs of the horse, supports appropriate body condition, and fits the owner’s management goals, budget, and forage availability.
References
Ball, D.M., Bade, D. N., Lacefield, G. D., Martin, N. P., and B. W. Pinkerton. 1998. Minimizing Losses in Hay Storage and Feeding. National Forage Information Circular 98-1. Graphic Center, Sacramento, CA.
Ball, D.M., Hoveland, C. S., Lacefield, G., D. 2007. Southern Forages: Modern Concepts for Forage Crop Management. IPNI.
Ermers, C., McGilchrist, N., Fenner, K., Wilson, B., & McGreevy, P. (2023). The Fibre Requirements of Horses and the Consequences and Causes of Failure to Meet Them. Animals, 13(8), 1414. https://doi.org/10.3390/ani13081414
Henneke, D. R., Potter, G. D., Kreider, J. L., & Yeates, B. F. 1983. “Relationship Between Condition Score, Physical Measurements and Body Fat Percentage in Mares.” Equine Veterinary Journal 15 (4): 371–372. https://doi.org/10.1111/j.2042-3306.1983.tb01826.x
Liburt, N. 2026. Nutritional Requirements of Horses and Other Equids. Merck Veterinary Manual. https://www.merckvetmanual.com/management-and-nutrition/nutrition-horses/nutritional-requirements-of-horses-and-other-equids#For-More-Information_v51038865
Martinson K, Wilson J, Cleary K, Lazarus W, Thomas W, Hathaway M. 2012. Round-bale feeder design affects hay waste and economics during horse feeding. Journal of Animal Science. 1;90(3):1047-55. https://doi.org/10.2527/jas.2011-4087
National Research Council. 2007. Nutrient Requirements of Horses. 6th rev. ed. Washington, DC: National Academies Press. https://doi.org/10.17226/11653
Phillips, S. 2019. Weight Loss Strategies in Horses. J. Anim. Sci. 97(3). https://doi.org/10.1093/jas/skz258.264
Wassel, B. 2017. Solubilization of nonstructural carbohydrates as a function of soaking interval and water temperature in southern forages commonly fed to equids. Thesis. Auburn University. https://etd.auburn.edu/bitstream/handle/10415/5732/Wassel%2C%20Brooklyne%20Thesis%20.pdf?sequence=2&isAllowed=y
Witherow, B. 2025. The Significance of Chewing in Horses. UK Vet Equine. 9(1) https://doi.org/10.12968/ukve.2024.0035