What’s important about protein in horse feeds? Are there simple, clear answers to these protein related questions that keep popping up? Here’s some information to help you understand, explain, and market horse feeds that contain a range of protein levels and sources.

A customer says, “I can understand why my dog and cat need meat for protein. Why do horses need protein? They eat grass, don’t they?” Although the sources are different, dietary protein is essential for all animals. Carnivores, like dogs and cats, easily digest the protein in meat, while horses and other herbivores, or plant eaters, derive protein from forage and grain.

“Why is protein so important?”
Protein makes up a large part of the tissue in the horse’s muscles, blood, internal organs, and skeleton. The processes of growth, reproduction, and cell replacement require a constant supply of protein. Protein is a necessary part of hormones, enzymes, antibodies, and other vital elements of body function. Horses can manufacture some amino acids (the building blocks that make up different types of protein) internally, but about half as the required amino acids cannot be synthesized by the horse and must be obtained from feedstuffs.

“Can you explain the protein content of the feed?
Feed manufacturers are required to state the level of crude protein on a feed tag. Usually the wording is something like “crude protein not less than 12 (or 14 or 16) percent”. This means that if a horse eats 5kgs of a 12% protein feed daily, this ration has provided him with 600gms of crude protein. The remainder of the feed supplies fibre, energy, vitamins, and minerals.

“What other feedstuffs provide protein to horses?”
A large amount of a horse’s protein is supplied by forage. Pasture, grass, and grass hay average around 8% protein, whereas lucerne hay is about 15% protein. Protein levels in grass and hay are influenced by weather, plant maturity and other factors. Pasture and hay can be analysed to determine their exact protein content.

“Crude protein doesn’t sound very nourishing. Are there different ways to measure how much protein is in a feed?"
Crude protein percentage is based on the nitrogen content of a particular feed. Although this number is different from digestible protein (the amount the horse can actually absorb and utilize), the crude protein figure is helpful in comparing different feeds, but remember that it is the total amount of protein ingested by the horse each day and the quality of the protein supplied, which is important.

“Does a feed with a higher protein percentage give a horse more energy?”

More protein in a feed does NOT equal more energy. Energy in a feed comes mainly from the carbohydrate portion of the grains and the fat content of the mix, while protein is used to build and repair body tissues.

“Is there a danger in feeding too much protein?”
Protein that is provided beyond what the horse requires for maintenance of body tissues can be metabolized to fuel exercise. The process of turning protein into useable energy produces such as nitrogen, must be excreted in the urine. This excretion is the natural work of the kidneys, so the process does not harm a healthy horse in any way. A consequence of overfeeding protein is increased water consumption that leads to the production of more urine. Ammonia fumes in a poorly ventilated stable may contribute to respiratory problems, especially in young horses.

”Isn’t protein bad for young horses?”
Protein is absolutely essential for proper growth and development of young horses. In the past, it was thought that foals and weanlings fed large amounts of high protein feed developed skeletal problems, and “stable wisdom” interpreted, this means that excess protein was the culprit. However, research has never showed a link between high protein feeds and developmental problems in growing horses.

Current understanding is that orthopaedic problems are most commonly seen in foals that experience rapid growth spurts, triggered by feed intake that is too high in energy.

It is common for high protein feeds to also offer high levels of carbohydrate, possibly oversupplying both requirements.

Orthopaedic problems in young growing horses can also be related to grazing, overrich pastures. Feed related risk of deformity can be minimized by management that allows steady, moderate growth, avoiding extremely high energy, dense rations.

”What happens if a horse doesn’t get enough protein?”
Young horses need high quality protein in order to grow steadily. While good quality hay and oats might keep a mature horse in good condition, this diet is deficient in lysine and amino acid that are essential for proper growth. Feeds designed for young horses often include; soybean meal, lucerne, or other lysine rich ingredients. Older horses require lower levels of protein for tissue maintenance and repair. Poor coat condition, loss of appetite, and lowered immune response are signs of protein deficiency in mature horses.

“There are so many factors to consider. How can I decide what to feed my horse?”
Base the equine diet around good quality forage, and supplement with a nutritionally balanced concentrate feed as needed to support growth, reproduction, or performance. Equine nutritionists have worked out formulations and feeding directions to provide superior nutrition to all types of horses. Capstone feeds and their representatives in this field can help an owner select a product that is correct for each situation.