Horse Tales: Nutritional value of hay and making sense of hay analysis results

During this time of year our horses are very dependent on their supply of hay to get them through the winter. It’s a nice, satisfying feeling when the hayloft is full, knowing our horses will have plenty to eat in the cold months, as hay represents the bulk of their diets in winter.
However, knowing the nutritional value of that hay is important — and a horse’s requirements will vary widely depending on its age, sex, condition and classification.
The best way to determine whether your horse is being adequately fed is to have your forage analyzed. As mentioned in last month’s Horse Tales, we brought a sample of our hay to our local Cornell Cooperative Extension office and filled out the required form for submission to the Forage Laboratory in Ithaca, NY. I received the results via email in just a few days, and a written report of the analysis results within a week of sending out the sample.
The analysis results were a bit confusing to interpret, as there were a number of unfamiliar values listed under the Components column; and two columns to the right, As Sampled Basis and Dry Matter Basis, showed different results.
I sent an email to the Customer Support person that had sent my report and asked for assistance in figuring out how to read the analysis results. I was told that my sample was analyzed as a (325) Forage NIR package which is under their Dairy One website, but Equi-Analytical is a subsidiary of Dairy One — basically is the same company, laboratories, and technicians, but sends different report formats. She sent a link that better matched the package I was sent, and noted that while some of the parameters listed (such as energies NEl, NEM & NEG) that appeared on my report are geared toward dairy cows, cattle and other ruminant animals, the DE energy value shown would be appropriate for the Equines and single stomach animals. She said in comparing my results I should be using the “Dry Matter” values rather than the “As Sampled” values. She sent a document titled “Understanding my Forage Analysis” in the hopes that it would prove to be more helpful. The chart provided information based on samples the company tested from grass hay samples sent in that were accumulated from crop years May 1, 2000 – April 30, 2016, and provided an Average, Normal Range and Standard Deviation. It was not made clear to me if the Normal Range was the range for optimum horse nutrition, or if it was the “normal” range of all those thousands of samples analyzed.
Deciding to do some more in-depth research, I typed “ideal hay analysis for horses” in my internet browser, and came up with an article titled “How to Interpret Your Hay Analysis Report: the Basics”, written by Juliet M. Getty, Ph.D that was useful in helping me understand the results of my hay analysis.
Some of the basic parameters used in analyzing a hay sample, and an explanation of the importance of each, are listed below:
Crude Protein (CP) is not representative of the protein quality but is rather based on the amount of nitrogen present in the hay. Most grass hay contains 8-10 percent crude protein; legume hay, such as alfalfa or clover, has a much higher percentage of CP, generally from 17–20 percent. With a reading of less than 8-10 percent protein, a horses would need to eat more hay to make up the difference — or you can feed a mix of grass and legume hay to provide a higher quality protein which helps maintain and repair tissue in their diet. Generally grain hay, such as that from oats or rye, contains a lower CP than grass hay.
Acid Detergent Fiber (ADF) and Neutral Detergent Fiber (NDF) are a measure of two of the five fibers present in the hay. They are digested by the microbes present in your horse’s cecum and large colon, and therefore a healthy population of these microbes is important for your horse to derive needed calories from the fiber. An ideal ADF value is less than 31 percent, and ideal NDF is less than 50 percent. If these values are much higher, the horse will need to consume more hay, which can be done by allowing your horse to have free access to hay 24 hours a day.
Lignin is actually an indigestible fiber. The amount of lignin in a plant increases as the plant matures; if your hay was late-cut it will contain more lignin and your horse will not benefit from this hay; she may find it unpalatable, and much will end up being wasted or passed through in the manure.
Water-soluble carbohydrates (WSC) measures the simple sugars and fructan levels in the hay. Simple sugars are digested in the horse’s foregut (the foregut of the horse includes the esophagus, stomach, and small intestine) and raises insulin levels. Too high a WSC value can lead to laminitis because of elevated blood insulin. Starch, like simple sugars, is also normally digested in the foregut down to the individual blood sugar) molecules, and also can have a strong effect on elevating blood insulin levels.
Fructan, on the other hand, is digested in the hind gut — including the cecum, large and small colon. Too much fructan can also result in laminitis caused by endotoxins in the bloodstream.
The two percentages, WSC and starch, are added together to reveal the total amount of sugar, starch, and fructan in the hay, which is called Non-Structural Carbohydrates (NSC).
You probably will not see a value for NSC. This is an important value to be aware of, however, if your horse needs to have a low sugar/low starch diet. The percentage of NSC should be less than 13.0 percent. Again, this percentage is found by adding the WSC and starch values. If the percentage of NSC in your hay tests higher than 13.0 percent and you have an insulin-resistant horse or one with Cushing’s Disease and you need to reduce the amount of sugar and starch in her diet, you can soak the hay to lower the levels of carbohydrates. Soaking hay also has the bonus of decreasing the allergens and dust in the hay, which will help a horse with “heaves”.
Ethanol-soluble carbohydrates (ESC) is a subset of the Water Soluble Carbohydrates, and provides you a better idea of just the simple sugar level. If you take the percentage of the WSC and subtract the percentage of the ESC, you will have a measurement of fructan levels. Ideally, the percentage of ESC + Starch should be less than 11 percent on a dry matter basis for a horse with equine metabolic syndrome or PPID (Cushing’s disease).
Minerals generally tested for include calcium, phosphorus, magnesium, iron, zinc, copper, manganese and selenium. The first three need to be in a proper ration in order for the horse to receive the benefit of each.
The calcium to phosphorus ratio should ideally be 2:1, with more calcium than phosphorus in the hay. Most grass hay (except orchard grass) will have this balance. The level of calcium can be higher than 2:1 and still be considered safe, but the percentage of phosphorus must never be higher than the percentage of calcium.
The calcium to magnesium ratio should ideally have the calcium content not be more than twice that of magnesium. Most hays contain less magnesium than what horses ideally require, and that magnesium is not well absorbed.
Ideal iron, zinc, copper, and manganese ratios should have iron no more than five times that of zinc; copper: zinc: manganese a value of 1:3:3. Remember that minerals interact with one another, and will interfere with the horse’s ability to absorb them. If your hay is close to these ideal ratios, it’s best to be conservative when supplementing these minerals.
Care should be taken before supplementing selenium in your horse’s diet, as too little selenium can be just as damaging as too much. It’s a good idea to know the amount of Selenium present in your hay before you supplement.
As with any question or change in your horse’s diet, it’s a good idea to consult an expert in the field. Your local Cooperative Extension Office can be very helpful, as was ours when I inquired.
Our Agriculture Educator II, Michelle Lipari, offered to provide an in-depth analysis of how our hay ‘stacks up’, so to speak, with what our horses’ nutritional needs are and how they are met. More information on nutrition, hay and supplements to come in next month’s Horse Tales!

2018-03-15T15:35:43+00:00March 15th, 2018|Mane Stream Articles|0 Comments

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