Optimal Nutrition for Weanlings

Weanlings, despite their small size, have intensive nutritional needs that are often overlooked, with many being fed like miniature adults. It is crucial not to underestimate the importance of a well-rounded feeding plan tailored to meet the specific calorie, mineral, and vitamin requirements of these growing horses.

At four months, weanlings exhibit higher daily total mineral needs than they do as yearlings, even though their daily calorie needs are lower. During this period of rapid growth, it is imperative to provide nutrient-dense diets with elevated levels of protein/amino acids and minerals per calorie. Attempting to feed weanlings the same diet as adult horses is not only insufficient but can have severe consequences.


Contrary to popular belief, managing calories for weanlings is not a complex task. In fact, many weanlings are overfed, a practice linked to developmental orthopedic disease. A six-month-old weanling requires 7% fewer calories than it will at full adult weight. By feeding the weanling 93% of the adult diet, not only will it receive the appropriate calorie intake, but it will also obtain 7% less protein and minerals.


Weanlings cannot generate the minerals needed for growth from their diet, and the stockpiles at birth are minimal. The disparity between the mineral needs of weanlings and adults is most evident at six months, where the weanling requires nearly twice as much calcium and phosphorus as it will as an adult. A mere 93% of the adult diet falls significantly short, leaving the weanling potentially deficient by up to 20 grams of calcium.


While calorie requirements decrease, protein needs increase by 7%, with lysine requirements rising by 10%. If the adult diet is reduced by 7%, the protein and lysine gap widens. For a horse maturing to 500 kg, this results in a deficit of 90 grams of protein and 4 grams of lysine. Many adult diets may not be adequate for lysine in the first place.

The Solution

To address these nutritional challenges, fortify the adult diet with modest levels of grain/concentrates specifically tailored for weanlings. Adjusting the adult diet to meet weanling needs is neither difficult nor expensive but yields significant benefits in terms of growth, health, and soundness.

  1. Assuming the adult diet meets minimum protein and mineral requirements, consider a supplement with approximately 25% protein, at least 1.5% lysine, 5% calcium, and a balanced mineral profile. Feed 1 pound per day of this supplement.
  2. If you are already providing supplemental minerals, introduce an unsupplemented high-protein source with at least 40% protein, 2% lysine, and a blend of milk/whey protein with vegetable sources. Feed 1/2 pound per day. If total protein is sufficient but primarily from hay with unknown lysine content, supplement with an amino acid supplement containing 10 grams lysine and 2 grams threonine per dose.
  3. In the absence of pasture during fall and winter, consider incorporating essential fatty acids into the diet. Omega-3 fatty acids, crucial for eye and heart health, are often compromised during hay curing and storage. Flax and chia, providing 4 to 6 ounces per day, are excellent sources of these essential fatty acids.

    By Staff writer