PSU Horse Barns Web Project
Dr. Nancy Diehl, Instructor

Grain Fed to Horses at Penn State University

Louisa Walker

Introduction to Grain

Grain is a common part of a horse’s diet. It can consist of a variety of types, such as oats, corn, or it can refer to “sweet feed” which is grain mixed with molasses. However, the primary source of nutrition for a horse should come from forages. If their energy needs cannot be met by forages alone, then grain or other concentrates should be used. Generally, grain should not be fed at more than 0.5% of the body weight of the horse per feeding. This means that you should not feed more than 5 lbs of grain for a 1000 lb horse per feeding. This is because carbohydrates are converted to lactic acid in the hindgut. Too much lactic acid, from a carbohydrate overload, will kill the good microbes in the hindgut. This may cause the horse to colic or result in poorer conversion of feed to energy and body mass.

Figure 1, This is the grain mix that we feed at Penn State. You can see the corn, oats, and a bit of the fines which is the soybean meal, dicalcium phosphate, and trace salt.

Grain Mixes

At Penn State, the horse barns use a standard formula to create their grain mix as given by Table 1 below. This mix is then fed to all the horses, mares, yearlings, 2-year-olds, and the stallions.

Table 1: Penn State Grain Mix
Oats	735 lbs
Trace mineral salt	7lbs
Dicalcium Phosphate	7lbs
Corn	185.5 lbs
Soybean Meal	42 lbs

Other nutrients and supplements could be included in the grain mix in accordance to the nutritional requirements of your horse. These could include linseed meal, bran, molasses, salt, limestone, and a variety of extra vitamins, and minerals.

Basic Grain Analysis

It is important to get a grain analysis done on your feed, particularly if you mix your own grain, as Penn State does. It is usually safe to assume that commercial feeds have already balanced their nutrients, but make sure that you always look at the tag for the proper proportions to feed the horse.

The important things to look for on a grain analysis is the Horse Digestible Energy (DE), total Horse Digestible Nutrients (TDN), crude protein, lysine, calcium, phosphorus, magnesium, and others (NRC 39). On most grain analysis the Horse DE and TDN will not be calculated out for you. These can be calculated for a horse at maintenance with the following formulas:

Horse DE (Mcal/lb): 1.85 – (0.025 x ADF [Acid Detergent Fiber])

Horse TDN (%): DE/0.02; unit of %DM
(calculations compliments of Virginia Ishler, Penn State)

All values should be calculated on a Dry Matter basis.

Penn State’s Grain Analysis

Table 2: Total Ration requirements from Horse NRC , Mature horse at maintenance.
Crude Protein	8.5 % DM
Calcium	0.30 % DM
Phosphorous	0.20 % DM
Magnesium	0.10 % DM
Potassium	1.0 % DM
Iron	60 ppm

Table 3: Penn State Grain Analysis
Crude Protein	13.5 % DM
Calcium	0.09 % DM
Phosphorous	0.41 % DM
Magnesium	0.14 % DM
Potassium	0.48 % DM
Iron	149 ppm

According to Penn State’s Grain Analysis, the Horse DE for their current mix is 1.395 Mcal/lb; with a Horse TDN of 69.75 %DM. A horse at maintenance weighing 1100lb/500kg Has DE requirement of 16.4 Mcal per day (NRC page 43). It is helpful to note that the standard amount of grain fed to Penn State broodmares in mid-gestation is 4.5lbs, 2 times a day, equaling 9lbs a day total. With this information we can take the 1.395 Mcal/lb from the current Horse DE and multiply it by the 9lbs a day (1.395 Mcal/lb X 9 lb/day) which would equal 12.5 Mcal/day. This is short of the 16.4 Mcal/day that is recommended by the NRC. However, the 16.4 Mcal/day is for the total ration. The horses at Penn State are also given hay and grasses which make up the difference.

Vitamin and Mineral Amounts in the Grain Analysis and Total Ration

The NRC also gives suggestions for the amounts of vitamins and minerals that should be found in a total ration for the horse. This can be seen in Table 2. The results from the Penn State Grain analysis can be seen in Table 3. Penn State seems to have plenty of iron, magnesium, and phosphorus to already meet the requirements for the total ration in just the grain. The calcium and potassium requirements are likely met with the hay and grasses that they are also fed. If anything, horses ingest excess potassium for their needs from forages. However, the main concern is with a Quarter Horse that has HYPP (Hyperkalemic Periodic Paralysis). It is a muscular disease characterized by episodes of muscular weakness, tremors, or paralysis due to an inherent genetic defect.

Feeding Grain

Each production group at Penn State receives different amounts of the grain to try and meet their individual nutritional requirements. The production groups are broken down into Mares, Yearlings, 2-year-olds, and Stallions. Table 4 shows the amount of grain that is fed to each production group, provided by Dr. Ed Jedrzejewski.

The lbs of feed that are given to the horses are based on a balanced ration analysis. Different feed types may require variable amounts of grain to be fed to the horse. You also need to take into consideration the individual needs of your horse, which may change the type and amount of grain you feed.

Table 4: Production Group	Amount of feed per horse
Mares	4.5lbs of grain 2 times a day
Yearlings	4.5lbs of grain 2 times a day
2-year-olds	Approximately 5 – 5.5lbs of grain 2 times a day
Stallions	4.5lbs of grain 2 times a day for two of the stallions; 4.5 lbs of oats and 3lbs of corn 2 times a day for the other two stallions.

Problems specific to Feeding Grain at Penn State

Figure 2, Grain Buster that is used at the horse barns to crack the oats.

Figure 3, Grain bin

Horses in different stages of production need different nutrition requirements. Penn State addresses this problem to an extent by customizing the amount of grain fed and the types of hay fed to the various production groups.

Another issue with the grain is that the horses have a tendency to not eat the fines, leaving behind valuable vitamins and minerals. Penn State does not top dress their grain, since in a group feeding situation, the horse to the grain first would get most of the vitamins and minerals. One of the options to make sure the horses get more of the fines is to add a binding agent, such as molasses. However, given the current facilities, grain buster shown in Figure 3 and a silo in Figure 4, this would not be a feasible solution. The current mixer cannot handle a wet mix, additionally, because the areas where the grain is mixed and stored is not climate controlled, the binding agent would likely freeze in the winter and become rancid in the summer.

A final concern is that the grain is rather dusty, as can be seen in Figure 4. This dust can irritate the respiratory tract causing problems in horses that may have allergies or are prone to heaves. This can be fixed by wetting down the grain to reduce dust content.

Figure 4, Dust rising off the grain mix as it is poured into a bucket. Penn State doesn’t use a binding agent, which would cut down on the dust.

One option would be to eliminate the grain altogether and use a complete pellet feed. Although still providing a single concentrate to all different production types, this would help fix many of the problems with the Penn State grain mix. It would be balanced if fed in the correct amounts, it would eliminate the problem with the fines as a pellet feed would not have any, and it would not be as dusty as the mixed grain.

However, nutrition should also be evaluated by outcome, in terms of the health and productivity of the horses being fed; it should be noted that the Penn State horses do fine on the grain/hay combinations that they are fed. Penn State sees minimal problems with developmental orthopedic disease or any other health concerns in the horses that are directly referable to their nutrition. Also the horses are usually turned out most of the time and Penn State has good pastures which add to the quality of the overall feeding plan for the horses.

Conclusions

Grain is a common part of most horses’ diets and it should fit into the horse’s overall nutritional plan. It is usually best to consult a grain analysis of your feed to help in formulating a ration for your horse, as well as the NRC requirements for horses. There are some problems with feeding grain which should be minimized, such as horses sorting feed and leaving the fines. The decision that farms, including Penn State, make to feed all their horses the same grain mix can be based on the efficiency of running the operation. In addition, with forages being the basis for the feeding program, the need for different types of grain is minimized. Carefully determine the nutritional requirements of your horse, and plan to meet that using forages and grain supplement as needed.

Works Cited

National Research Council. Nutrient Requirements of a Horse. Fifth Revised

Edition. The National Academies Press, 1989 Available at:

http://www.nap.edu/books/0309039894/html/

The content of this web page was produced by students in our Advanced Horse Production and Management (AnSc 407, 2004) course at Penn State. This page is not a product of the Equine Science Team. As such, it is intended for educational and entertainment purposes only. For recommendations specific to your farm or horse you should consult your equine veterinarian, local horse professional or County Extension Agent.

Where trade names appear, no discrimination is intended, and no endorsement by Penn State's College of Agricultural Sciences is implied. Issued in furtherance of Cooperative Extension Work, Acts of Congress May 8 and June 30, 1914, in cooperation with the U. S. Department of Agriculture and the Pennsylvania Legislature. T. R. Alter, Director of Cooperative Extension, The Pennsylvania State University.

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