Nutritional Changes Through Your Horse’s Life Stages

Life stage is one of the most important factors in deciding what to feed your horse. Life stage classifications range from weanlings and yearlings to adult and aged horses. Then, other considerations, including activity level and health, must be taken into account to determine their daily nutrient requirements.

Horse's Nutrition From Birth to Two Years of Age

Within just a few weeks of being born, foals start to explore and eat solids, mimicking their dams. Even though foals get most of their nutrition from the mare’s milk, we recommend that horse owners introduce a creep feed, such as Foal Foundation, to assist their growth and cover any nutritional gaps. At this stage of life, a foal’s digestive system can only digest milk-based proteins, thus a quality creep feed is always recommended. At this time, it is not appropriate to give them a feed designed for more mature horses. When a foal reaches the 3-month age mark, they can start to digest plant-based proteins. You can learn more about creep feeding HERE.

Weanlings are young horses older than 3 months of age, but not yet 1-years old, although most horses aren’t weaned from their dams until at least 4 months of age and most often, closer to 6 or 7 months of age. At this age, the horse is either nursing less or is completely weaned off their mother. It is also a period of tremendous growth. For most breeds, young horses reach nearly 80% to 85% of their potential height in just their first year of life. Thus, this is a dynamic period where young horses experience growth spurts and their nutritional demands can be at their highest.  According to the National Research Council, some of the daily nutrient requirements for a weanling are estimated to be:

  • 1.40 Mcal/lb. (calorie portion of the diet)
  • 14.5% Crude Protein
  • 0.60% Lysine (limiting amino acid)
  • 0.68% Calcium and 0.38% Phosphorus (nearly 2:1 ratio)
  • 720 (IU/lb.) Vitamin A

Yearlings are young horses that are older than 12 months of age, but not yet 2-years old. For some horse breeds, growth will slow down at this point. Yet, for slower growing breeds, like our draft type horses, they may continue to experience some rapid growth into their second year of life. According to the National Research Council, some of the daily nutrient requirements for a yearling are estimated to be:

  • 1.30 Mcal/lb. (calorie portion of the diet)
  • 12.6% Crude Protein
  • 0.53% Lysine (limiting amino acid)
  • 0.43% Calcium and 0.24% Phosphorus (nearly 2:1 ratio)
  • 980 (IU/lb.) Vitamin A

It is very important to remember that we must carefully monitor our young, growing horses. This is because they are prone to Developmental Orthopedic Disorders (DOD) that can be linked to their nutrition. If you are feeding young horses, our articles on feeding and the danger of DODs is highly recommended to review HERE and HERE.

When a horse at any stage of life enters training, it will obviously affect their nutrient requirements. They will require more energy, protein (amino acids), trace minerals and vitamins to support their continued growth and increased activity. However, in general terms, once a horse reaches 2-years of age, their diets are generally formulated like that of an adult horse. According to the National Research Council, some of the daily nutrient requirements for adult horses on a maintenance diet are estimated to be:

  • 0.90 Mcal/lb. (calorie portion of the diet)
  • 8% Crude Protein
  • 0.28% Lysine (limiting amino acid)
  • 0.24% Calcium and 0.17% Phosphorus (nearly 1:1 ratio)
  • 830 (IU/lb.) Vitamin A

Nutrition For Mature Horses

When a mature horse is in training and undergoing a moderate level of work, all of their nutrient requirements shift upwards. According to the National Research Council, some of the daily nutrient requirements for a mature horse at a moderate level of work are estimated to be:

  • 1.20 Mcal/lb. (calorie portion of the diet)
  • 10.4% Crude Protein
  • 0.37% Lysine (limiting amino acid)
  • 0.31% Calcium and 0.23% Phosphorus (a 1.5:1 ratio)
  • 1100 (IU/lb.) Vitamin A

Other life factors will also influence these quoted values. For example, stallions require more nutrients than a mature horse at maintenance. Likewise, pregnant and lactating broodmares have nutrient requirements like those of young, growing horses, dependent on their stage of pregnancy and lactation. According to the National Research Council, some of the daily nutrient requirements of a lactating broodmare for the first 3 months following birth are estimated to be:

  • 2.60 Mcal/lb. (calorie portion of the diet)
  • 13.2% Crude Protein
  • 0.46% Lysine (limiting amino acid)
  • 0.52% Calcium and 0.34% Phosphorus (nearly 2:1 ratio)
  • 1250 (IU/lb.) Vitamin A

Nutrition For Senior Horses

The final life stage of a horse is in their senior years. When a horse enters their senior years will depend on that individual animal. This is a time when their nutrient requirements will generally shift upwards due to a decrease in digestive ability. You can learn more about feeding a senior horse HERE.


The take home message: feeding your horses across all life stages is very dynamic. The above quoted values are only meant to illustrate how these nutrient requirements differ across life stages and are the baselines used to formulate a horse’s diet. If you have any questions or need any advice on your horse, please contact us for a free, personalized feeding plan.

Article By: Chris Mortensen, Ph.D.
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