Hay may not be enough for your thoroughbreds protein intake.

It is true that horses can maintain their body condition well on forage (grass or hay) alone, but she’s worried he does that mean that horse is getting enough protein in their diet. Dr. Clair Thunes explains whether horses can get enough protein from eating hay alone.

Mature Horses’ Protein Requirements

According to the Equi-Analytical feed database, on average, grass hay provides only 10% crude protein on an as-fed basis. A 1,100-pound horse at maintenance has a crude protein requirement of 630 grams. If fed 2% of the horse’s body weight (22 pounds) of this grass hay, the horse will ingest 1,000 grams of protein. This seems like enough protein to fill the horse’s needs. The same horse in a very intense work routine requires about 1,004 grams of crude protein each day. Hay at this intake can meet a broad range of requirements.

Protein content can vary by hay type. Legumes provide significantly more than grass hay while grain hays provide less. If you do the same calculations feeding the same horse the same amount of oat hay with 7.5% crude protein, the protein intake is 750 grams. This is enough for a nonworking horse, but not enough to support a hard-working horse’s needs.

If the amount of hay is restricted to 1.5% of body weight as in the previous scenario, the grass hay will provide 750 grams of crude protein (which is still okay for the horse at maintenance) while the oat hay will only provide 563 grams. This is below even maintenance requirements. In these cases, it’s not that the hay cannot provide enough protein, but, rather, how the hay is being fed that dictates whether it is enough. This is what creates the issue.


More Protein, Please

Protein content becomes much more of a concern when feeding lactating broodmares and growing young horses, especially those horses under one year old. If a 500-kilogram horse was a broodmare in the second month of lactation, her crude protein requirement would be 1,530 grams each day. A 6-month-old weanling with an expected mature weight of 500 kilograms would require 676 grams of protein each day. The latter amount seems easy to meet until we remember that this newly weaned horse likely only weighs about 475 pounds. Even if he’s eating 2% of his current body weight, he would only be consuming about 430 grams of protein from the grass hay and 322 grams from the oat hay. This is exactly why most lactating broodmares and young horses need additional supplemental protein and nutrient sources in their diets. If your lactating broodmare or growing young horse is in need of protein supplements in addition to the hay that the horse is consuming, then check out the protein supplements at RIGHT HERE.



The Bottom Line

Horses do not actually have a requirement for crude protein. What they require are the amino acids that make up protein. Some amino acids are essential and must be provided in the diet as a horse’s body can’t produce them. Horses can make other amino acids, which is why they’re considered nonessential in the diet. The greater the proportion of essential amino acids there are in a protein, the better the protein quality. Therefore, it is possible that hay could provide enough protein but it might not be the best quality.

That said, because we typically feed significantly more total crude protein in the diet than required, most of the mature horse’s essential amino acid needs will be met. If your horse is having problems with issues such as poor hoof, skin, or coat quality; poor topline development; or slow wound healing, it might require a source of better-quality protein than the hay is providing. In such a situation a high-protein ration balancer might be a good option.


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