Although I feed KER-formulated feeds purchased from Saracen Feeds, many people feed bread to horses in the region of Italy where I live. I believe bread fattens horses and contains an inappropriate balance of calcium and phosphorus. Are there other concerns with feeding bread? Some horse owners feed only bread and hay, even to broodmares and foals, and I fear these horses aren’t receiving all of the nutrients they need.
Assuming that the bread is made with wheat flour, yeast, salt, and water, there is nothing in it that is toxic to the horse, and it can contribute enormously to caloric intake if fed in large quantities. There is no harm in occasionally feeding bread, but it is not the most nutritious feedstuff when used as the sole concentrate. While bread is chock full of calories, it provides few nutrients.
When only bread is fed with hay, the major nutritional problem is an imbalance and/or deficiency of some minerals and vitamins. Wheat is deficient in vitamins A, D, and E, as well as trace minerals like zinc, copper, and selenium. All of these play important roles within the body. When horse owners purchase KER-formulated concentrates, there is no need to worry that sufficient essential nutrients are consumed as long as horses are fed recommended amounts. Conversely, when something is fed that is not specifically designed or formulated for horses, it might not supply all the nutrients needed by the horse and it might shift the nutrient balance of the total diet.
For example, if the calcium requirement for a horse is 32 grams per day and a given amount of grass hay supplies 20 grams, a fully fortified concentrate could easily deliver the remaining 12 grams of calcium. Because bread is not made to balance the forage-based diet of the horse, it probably does not have the calcium necessary to meet requirements.
In fact, wheat is low in calcium, so the chances of the bread providing the 12 grams of calcium are slim. Wheat is not, on the other hand, low in phosphorus, so it will probably supply sufficient phosphorus. When there is more phosphorus than calcium in the diet, interference in calcium absorption occurs and further exacerbates the calcium deficiency. Without enough calcium in the diet, the horse’s body will start pulling the mineral from its bones and weakening them and severe calcium deficiency can cause secondary hypoparathyroidism (big head disease). The chance of this type of imbalance happening increases with the amount of bread fed. Lucerne(alfalfa) is abundant in calcium, so if bread were fed with this type of hay, calcium deficiency would not be a concern. However, the same deficiency problems may occur because of insufficient intake of trace minerals. If bread is used as the sole source of extra calories, the addition of a complete vitamin and mineral supplement is necessary.
The protein content of bread flour (13-14%) is marginally adequate for a growing horse or pregnant/lactating mare as long as the hay or pasture available also has acceptable protein content. If the hay has a protein content below 6%, there would be reason to be concerned about inadequate protein intake. Some type of protein supplement would be necessary to support the proper growth of young horses, whether in utero or on the ground.
The high starch content of bread may be a potential problem if fed in large amounts. Diets rich in starch have been the focus of much research lately because of their possible connection to certain health problems such as rhabdomyolysis and developmental orthopedic disease.
Another concern with a high-starch diet is the limited capacity of the small intestine to digest it, allowing large amounts to pass through to be fermented in the cecum and colon. Starch fermentation causes a buildup of lactic-acid producing bacteria in the hindgut and a subsequent drop in pH. The results can range from inefficient feed conversion (weight loss) to colic.
It is not customary to feed wheat grain to horses because of the high gluten content. The problem with wheat gluten balling up in the stomach or intestinal tract and causing blockage (colic) is not a concern with feeding bread because the yeast and the heat of baking have altered the gluten starch.
In summary, feeding bread to horses may be cost effective and is not harmful in limited quantities, but it is not ideal nutritional management, especially for young horses or pregnant/lactating mares.