What We Can Learn From a Hay Analysis

Everyone wants to do what is best for their horse, and that includes feeding an optimal daily ration. Picture yourself heading to the feed store to pick out a new product to feed your horse. Chances are that you have a general idea of what you want, whether a high-energy performance feed, or a simple ration balancer for your easy keeper. However, even within those categories there are a plethora of options. You will probably read the feed tags of at least a few products before deciding, because of course if you are feeding something to your horse, you want to know what is in it.

Now let’s flip the scenario; what if none of the products in the feed store had labels or nutritional information on them? It would be challenging to leave feeling confident in your decision, as you simply do not have any information to base your choice on. Scary, right?

Well, if that sounds like a terrible situation, why do we do that with hay? Simply roll the dice, hope for the best and that our horse does well on the hay, or make diet adjustments after they have started to have negative changes in body condition?

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A hay analysis is imperative, as it is like a feed tag. You wouldn’t feed your horse a product from the store with no label, so we shouldn’t think it is okay to do that with their hay.

A sample hay analysis chart.

What analysis tells you

First you need to know what values to look at on your hay analysis. There will be a “Dry Matter” column as well as an “As Fed” or “As Sampled” column. For comparing analyses, it is recommended to use the “Dry Matter” values, as this is the nutritional content with the moisture removed. Another important reminder is that when sending your hay analysis to a lab you want to ensure that you are selecting an equine-specific analysis. This will provide you with the important information described below:

Moisture

The moisture content of the hay is important, as we want to avoid any mould risk in our bales. For horse hay, the recommended range is about 8-15%. When hay has a moisture content greater than 15%, mould can become a concern. However, when the hay is too dry, the leaf matter will be brittle. You want to avoid this as the leaves hold most of the nutritional content, so when they are brittle there can be significant nutrient loss. With moisture it is important to remember that storage conditions of the bales can also play a factor.

ADF, NDF, Lignin

Acid detergent fibre (ADF), neutral detergent fibre (NDF) and lignin (organic polymer deposited in the cell walls which makes them rigid and woody) provide insight into how digestible the nutrients of the hay are as well as the content of indigestible fibre. ADF includes both cellulose and lignin, whereas NDF includes cellulose, hemicellulose, and lignin. Lignin is indigestible for horses, therefore, as these numbers increase, the digestibility of the hay decreases. For horses, you do not want to exceed 45% ADF or 65% NDF.

Digestible Energy

Digestible energy (DE) content provides you with information to balance the caloric content of your horse’s diet. The energy content will vary greatly – if we take the averaged value for mixed, mainly grass hay from the Equi-Analytical database (2004-2023), the range for DE content ranges from 1.83 Mcal/kg – 2.28 Mcal/kg. Therefore, if you have a very easy keeper that struggles to remain at a healthy body weight, it is going to be challenging to meet their long-stem fibre intake needs without providing excess calories if you have a forage that is at the top end of the range. On the other hand, if you have a hard keeper and the energy content of your hay is low, you will likely be spending a significant amount on supplemental feeds.

Crude Protein

The protein content of the hay will be influenced largely by the plant species and plant maturity. The protein content in grass hay tends to be lower (~6-12%) than legume forages (~15+%), with grass-legume mixes falling in the mid-range. For a horse at maintenance or in light work, about 10% crude protein is adequate. Horses that are in a higher plane of nutrition will require more; for example, horses in heavy work or lactating broodmares.

Sugar & Starch

For starches and sugars there are a few different values to look at. Forages are typically low in starch, but this value is important in the calculation of non-structural carbohydrates (NSCs). The two sugar values are ethanol-soluble carbohydrates (ESC) and water-soluble carbohydrates (WSC). ESC includes simple sugars and WSC includes both simple sugars and fructans. For calculating the NSC content, the Nutrient Requirements of Horses (2007) recommends using WSC + starch. However, in recent years, a debate has sparked around whether fructans should be included in the calculation. Therefore, if your horse is at risk of developing hyperinsulinemia-associated laminitis, or has PSSM, it is recommended to have your nutritionist or veterinarian review your hay analysis.

Minerals

Hay alone will not meet all of your horse’s vitamin and mineral requirements. However, it is also important to look at the values in the forage for any skewed ratios or abnormal values. The calcium-to-phosphorus ratio is recommended to be between 1:1 and 3:1, and most equine hay analyses will provide you with this value already calculated. The mineral content of your forage becomes important when you are choosing a supplemental source of vitamins and minerals.

Making nutritional decisions for your horse

Of course, the sugar and starch content will provide you with critical information on the safety of your hay if you have an at-risk horse. The moisture content will also contribute to understanding the safety of the forage.

From there, using the digestible energy, ADF, NDF, and lignin can assist you in choosing a hay that better matches your horse’s energy needs. For example, if they are an easy keeper, it makes sense to opt for a forage that is lower in digestible energy, as you will save yourself a lot of frustration in trying to reduce their hay intake. Additionally, if you have a hard keeper, it will be optimal to source a higher-energy hay with lower ADF, NDF and lignin.

For crude protein, both over-supplementation and under-supplementation negatively impact the horse. Therefore, if you receive your hay analysis results and the protein is adequate, you can save money and avoid over-supplementing your horse! It’s a win/win! Whereas, if the hay is low in protein, you can ensure that you are supplying adequate supplemental amounts prior to them losing muscle mass or resulting in a poor topline.

If you don’t have the luxury of testing your hay prior to purchasing, a hay analysis after purchase is still imperative to optimal nutrition. For example, if you have a hard keeper that has been doing well and you receive a new batch of hay, testing it and adjusting the supplemental feeds to that analysis can save your horse from potentially experiencing weight loss.

To summarize, hay is often over 90% of what a horse consumes on a day-to-day basis, therefore it only makes sense that you are equipped with the nutritional information of what is in it! Investing in a hay analysis each time you receive new hay can provide peace of mind and reduce the chances of nutritional problems, enabling you to adjust your supplementation choices before issues arise instead of in response to them.

If you have further questions about hay testing and how to optimize your horse’s nutrition, it is recommended that you consult a qualified equine nutritionist.