Hay! What Are You Feeding?

By Bernie Willis

Reprinted from The Icelandic Horse Quarterly: Issue Four 2004.
The Icelandic Horse Quarterly is the official publication of the US Icelandic Horse Congress. The magazine is printed four times annually and mailed to the membership. Back issues may be purchased for a small fee and may be read online at www.icelandics.org/quarterly.

What do you do when the love of her life dies? She was 12 then, her horse was 8. He was a handsome gray gelding. Along with her best friends, she rode often and 'was at our stable to visit her horse every day. Then one day he didn't eat in the morning. I was called to take a look. He stood like a statue. His temperature was normal, respiration was within range. No gut sounds at all. An Icelandic horse that doesn't eat is not good. Some treat perhaps? Not even a look of interest. A stone statue. If he'd shown some discomfort, wanting to roll or biting at his flank, it would have made me think of colic but something else was happening here. The young owner was becoming distraught because I didn't have answers for her. Obviously something was wrong, but what could we tell the vets that would make a difference for their analysis? Then she asked me, "What's happening here?" She had reached out to pet his neck and felt some strange reaction. There were tremors in his neck muscle on the right side. So we did have something more than "no gut sounds" to tell the vets. The call was placed and Dr. Joe was on his way.

Upon examination he wasn't sure of a diagnosis, but he thought some kind of poisoning was likely. He was convinced that a neurological problem was in evidence. He explained that there were many causes for symptoms like these. But to find the right treatment was difficult. To have a chance of saving Kalsi, he needed to come to the clinic. So we pushed and pulled the statue into the trailer and down the road we went. After the 45 minute ride he seemed better and walked into the clinic. But soon he stiffened up again. I don't know everything the vet did, but in a few days it was arranged to end the life of Kalsi. He was showing signs of severe pain and nothing was helping. Minutes later, after the doctor returned with the only source of comfort in his hand, the horse was dead.

I don’t wish the thoughts that ran through my head on anyone. First there were the tears of the young owner. Then the facts that the horse had been purchased from me and that it became sick at my stable.

And oh yes, the girl's father is a lawyer. We all did some soul searching and the hurt is gradually going away. My soul searching turned to finding reason for the problem.

One day I suddenly realized that I needed two international health certificates to attend a show in Canada. My usual vet wasn't available, so a new vet just out of vet school did the examinations. We got to talking about the recent tragedy in my stable. She was familiar with a similar situation with a Morgan horse. She asked about what I'd been feeding. I explained that Icelandic horses have lived for centuries on grass and that I was feeding good quality grass hay. Then she shared with me a message she had recently received from Cornell University on the vet hot line. The message said that recent research had determined that hay loses nearly all its vitamin E during twelve months of storage. The effect is that horses without fresh pasture or recently cut hay develop a vitamin E deficiency at about 16 months. The symptoms of vitamin E deficiency are the same as Kalsi's. She wondered, did I have another horse that had been fed the same as Kalsi for the same length of time? When I answered yes, she offered to take a blood sample to see what the vitamin E levels were. If you're guessing that they were low, you're right. In fact they were off the scale low. Immediately after notification, I began supplementation with lOOO IU per day. After three months another test indicated the horse was in mid range. Does this mean that Kalsi died from lack of vitamin E? Perhaps, but we'll never know for sure. What I do know is that my horses won't be low on vitamin E in the future. So what about all the other nutrients that horses need? How was I doing?

My next step was to contact Svanhildur Hall at the Hvanneyri Agricultural University, Iceland. She taught animal science and was very familiar with the Icelandic horse. I chose her because she was a graduate of Auburn University, Alabama, and would be familiar with my general situation. After some e-mail correspondence she referred me to Virginia Tech's Equestrian Department, because their basis for calculation was more universal than the "feed unit" system used in Iceland. This is what I learned.

The basis for these tables is an 800 pound or 363 kg horse fed for maintenance. A hard working or pregnant mare would have greater needs in some areas.

These are the common items listed on a feed analysis. Often they are listed on a percentage basis so a little math is needed to convert them to weight.

Energy 13,400 calories

Crude Protein 536 grams

Lysine 19 grams

Calcium 16 grams

Phosphorus 11 grams

Reading these tables it is evident that feeding 6 kg of hay requires 1200 IU of vitamin E to be adequate. Since there is some vitamin E in new hay, and a horse can store it for a couple months, the vet recommended a 1000 IU gel tab per day. Even on fresh grass pasture the horse would be within the upper limits. So we have made a decision on vitamin E, but what about the other required nutrients?

An analysis of hay done by your local Ag. University will give you the results for protein, calories or energy, calcium and phosphorus. This common test usually costs about 40.00. For a small additional fee you can get counts for each of the minerals. There are labs that will do an analysis for each vitamin, but the cost is over a hundred dollars for each one. When I pursued these tests one lab advised against it because of the extreme variability caused by storage conditions of the feed. You could easily get $300.00 involved in the tests for one hay sample. A more economical program would be to simply supplement the volatile vitamins. Vitamin and mineral imbalances can cause severe health problems and sometimes even death.

But inadequate protein and energy can lead to long term problems as well. This is why common hay analyses begin with protein. 8% to 15% on a dry matter basis is the usual recommendation.

These minerals and vitamins are listed on many feed supplements.

Magnesium .09 %

Potassium .30 %

Sodium .10 %: maximum tolerance level 3.0

Sulfur .15 %: 1.25

Iron 40 mg/kg of feed (if feeding 13 pounds or 6 kg of hay it equals 240 mg): 1,000

Manganese 40: 1,000

Copper 10: 800

Zinc 40: 500

Selenium 0.1: 2.0

Iodine 0.1: 5.0

Cobalt 0.1: 10.0

Vitamin A 2000 IU/kg: 16,000

Vitamin D 300: 2,200

Vitamin E 50: 35,000

Vitamin K: unknown

Thiamin 3 mg/kg: 3,000

Riboflavin 2 mg/kg: unknown

What are your options if the protein is too low? You must add feeds that are high in protein relative to their other nutrients. For instance alfalfa, a legume, is very high in protein but also imbalanced in the minerals phosphorus and calcium. So it must be used with caution. Another option is soybean meal or a blended supplement with soybean meal as an ingredient. A simple way to figure the ratios of protein or other feed ingredients is to use the following formula. Let's say your hay analysis indicates a protein level of 8 % but you want to feed protein at 10 %. The question is how much high-protein feed must be added to have a total protein of 10%. Take the normal weight of hay fed, multiplied by the target protein percentage, minus the current protein percentage, divided by the percentage of protein in the new high protein-feed.

Here's an example: 14 pounds of hay normally fed multiplied by .10 minus .08, or .02 multiplied by 14, which equals .28, divided by the protein level of the added feed, which in this case is soybean meal which is 47 percent protein. So we have .28 divided by .47 which equals .595 pounds. So with only a little over half a pound of soybean meal you can increase your protein level from 8 to 10 percent.

A few years back, while I was visiting in Europe, a proud Icelandic horse owner showed me the contents of a large chest freezer. It was full of a grain mixture of corn, oats and barley. We commonly refer to this as COB in this country. It is very palatable to horses and full of energy. This man knew what to feed to get the results he wanted. In his case he wanted very energetic horses. He lived for power and speed. When you look on a COB label for its analysis you'll see a protein level of around 10%. So it's not a supplement to increase protein but a good one to increase carbohydrates without the bulk of hay. Such feeds are commonly referred to as concentrates. Most authorities recommend a maximum of half of a daily feed ration be concentrates. This amount should be reached only after gradual increases over time. Icelandic horses usually have plenty of energy and don't need concentrates at all, except to provide a balance of nutrients.

If you're starting to wonder about what you're feeding, then I'm making my point. Take a sample for analysis, and for about $40.00 you can get either great satisfaction or direction to improve the nutritional situation for your horse. Each year I get several hay samples analyzed. It's a matter of health and economics. In my area local grass hay goes for about $240 per ton. Imported grass hay from Washington State sells for around $450 per ton. We know that feed value is not always equal to the weight of the feed, so knowing what's really in the hay determines what concentrates or other supplements are needed to make a balanced diet. The cost of these additives added to the lower cost hay may make the higher priced hay a better value.

Many Icelandic horse owners are urban folk with little experience as farmers. As far as many know, hay comes from the feed store and that's all they need to know. But if you're the curious type, here are some hay making concerns from the farmer's view point. If your economic security comes from the farm, then you need to sell for a fair price. To most farmers that means for as much as you can get. High quality means repeat customers, but high quantity means more money. In parts of Europe hay is now sold on the basis of its feed value, but in the U. S. it's still sold on weight or size unit basis. This creates a dilemma for the farmer. The longer he waits before cutting the more growth and the more tons per acre. But if he waits too long the protein will leave the leaves and go into the seed head. If he waits still longer the seed will ripen and fall to the ground leaving the protein level in the hay very low. Weather conditions often are the determining factor in hay cutting. In many areas the grass is cut and bailed within two or three days. But if it rains the hay must be turned or tedded to allow it to dry. Rain on drying grass reduces its protein content, as do additional days in the sun. Cutting before seed is formed and quick drying results in the highest quality hay. But sometimes this is beyond the farmers control. The fertility of the soil is another factor in the quality of the hay. The types and quantity of fertilizers used also affect the potential quality of the hay. Below you will find three abbreviated hay analyses done by the University of Alaska Fairbanks in 2004.

Sample from Bromefield,Skagafjordur farm, Iceland

Crude Protein %








Calcium %




Metabolizable Energy Mcal/lb




A quick review of this analysis indicates that each of these sample indicates adequate protein and enough energy at 13-14 lbs per day per horse weighing 800 pounds. But what about the phosphorus and calcium?

From above we noted that we need 16 and 11 grams respectively. So let's figure it out. From the Bromefield we have .19%. To convert that to grams we multiply .0019 times 14 pounds of hay fed. So you have .0266 pounds of phosphorus, or .0266 times 454 grams per pound and get 12 grams of phosphorus.

You could feed 19 pounds of hay or add a little bone meal. The extra hay would probably make your horse fat. But the hay would be enjoyed. The math procedure is the same for the calcium. You'll note that the Icelandic hay is adequate in both phosphorus and calcium.

Many of us have help around the stable. Do you. like me, wonder how much hay each horse gets? Do you know what a flake of hay really is? Usually when I ask, How much are you feeding? The answer will be, A flake or two? To know what makes a flake of hay you must understand how a baler of hay is made. A bailer is pulled by a tractor through the field. The dry hay has been raked into a long narrow pile. As the baler rolls along, a spiked cylinder picks up the hay and puts it in a chamber. Each time me cylinder makes a revolution, a plunger drives the hay in the chamber into a second chamber. In the second chamber another plunger adds the hay to the building bale. When enough plunger loads put the proper tension on an adjustable spring, the automatic knot tying finishes the bale and another is started. Each plunger load is a flake. The amount of hay in a flake is dependent upon the hay the spiked cylinder picked up in one revolution. If the baler went at the same speed and the hay grew evenly over the entire field, then each flake would be me same. But of course this is never the case. So feeding by flakes is not by weight. You'll come a lot closer to equal weight feedings if the same thickness of hay is fed each time.

One last nutrient concern, SALT. Why do horses need it? A lot of equine nutrition is similar to our own. But this is not the case with salt. The horse needs salt to assist in the osmotic regulation of body fluids. Sodium and potassium work together to regulate fluid content of cells. Potassium keeps them from drying out and sodium keeps them from filling with water. The amount of salt needed depends upon the work or sweating the horse does. For maintenance or lactation 8 to 12 grams a day will do. But heavy training may require 40 grams per day. It takes 102 grams of salt to supply 40 grams of sodium.

Free access to salt is recommended and loose salt is best for heavy users. With salt comes the need for water. Without salt and proper water horses will eat slower, develop rough haircoats and dry skin.

Learning how to take better care of my horses is fun and a lot cheaper than vet bills. Nutrition science is dynamic. Trying to keep up to date isn't always easy but it pays back in happier horses and lower overall costs of horse ownership. Knowing when to supplement and how much or not at all, can really affect the bottom line. Of all the books and articles I have on equine nutrition my favorite is Beyond the Hay Days by Rex A Ewing. It's published by Pixyjack Press, LaSalle, Colorado.

Official Publication of the United States Icelandic Horse Congress (USIHC), a member association of FEIF (International Federation of Icelandic Horse Associations).

The Icelandic Horse Quarterly is published in March, June, September, and December by the USIHC as a benefit of membership. Join online at www.icelandics.org/join. USIHC members are encouraged to submit articles and photos or illustrations for publication. Deadlines are January 1 (for the March issue), April 1, August 1, and October 1. Advertising rates and instructions are also online.

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