Why Feeding the Weanling Correctly Matters
Weaning is one of the most stressful transitions in a young horse's life. Between the ages of roughly four and eight months, the foal goes from relying on its dam's milk for a significant portion of its nutrition to depending entirely on forage, concentrates, and supplements. How you manage this dietary shift has a lasting impact on bone development, joint health, muscle growth, and even temperament.
Get it right, and you lay the foundation for a sound, athletic adult horse. Get it wrong, and you risk developmental orthopaedic disease (DOD), poor topline, weak hooves, and growth abnormalities that can follow the horse for life.
This guide covers everything you need to know about feeding the weanling — from energy and protein requirements to mineral ratios, forage choices, and the mistakes that catch even experienced breeders off guard.
Understanding the Weanling's Nutritional Needs
A weanling is not simply a small adult horse. Its digestive system is still maturing, its skeleton is rapidly mineralising, and its overall growth rate is at one of the highest points it will ever reach. Nutritional requirements per kilogram of body weight are significantly greater than those of a mature horse.
Energy Requirements
Weanlings typically need between 13.5 and 15 megacalories (Mcal) of digestible energy per day, depending on breed, expected mature weight, and current growth rate. For context, that is roughly 30-40% more energy per kilogram of body weight than a horse at maintenance.
However, more energy is not always better. Overfeeding energy — particularly from starch and sugar — is one of the leading dietary risk factors for DOD. The goal is steady, moderate growth, not maximum growth rate.
Protein and Amino Acids
Protein is critical for muscle development, organ growth, and immune function. A weanling's diet should contain approximately 14-16% crude protein on a total diet dry matter basis. But crude protein alone does not tell the whole story.
The quality of protein matters enormously. Lysine is the first limiting amino acid in horses, meaning that if your weanling's diet is short on lysine, it doesn't matter how much total protein you provide — growth will be compromised. Aim for at least 30-35 grams of lysine per day for an average weanling expected to mature at around 500 kg. Threonine and methionine are also important for optimal growth.
Good sources of quality protein for weanlings include soybean meal, alfalfa (lucerne), and specifically formulated youngstock feeds.
Minerals: The Non-Negotiable Foundation
Mineral nutrition in the weanling is arguably the single most important — and most commonly mismanaged — area of young horse feeding.
#### Calcium and Phosphorus
Calcium and phosphorus are the primary building blocks of bone. A weanling needs approximately 36 grams of calcium and 20 grams of phosphorus per day (for a foal expected to mature around 500 kg). The calcium-to-phosphorus ratio should stay between 1.5:1 and 2:1. An inverted ratio (more phosphorus than calcium) can lead to serious skeletal problems.
#### Copper and Zinc
Copper and zinc play essential roles in cartilage and bone development. Copper deficiency is strongly linked to osteochondrosis (OCD), one of the most common forms of DOD. Weanlings need approximately 75-100 mg of copper and 300-400 mg of zinc per day. Many pastures and hays in the UK, Ireland, and Australia are deficient in copper, so supplementation is often necessary.
#### Other Trace Minerals
Manganese (200-400 mg/day), selenium (1-1.5 mg/day in total diet), and iodine also support healthy skeletal and thyroid development. Iron is almost always adequate in forage and soil and rarely needs supplementation — in fact, excessive iron can interfere with copper and zinc absorption.
Vitamins
Vitamin A and vitamin E are the two vitamins most likely to be marginal in a weanling's diet, particularly for those on conserved forage during winter. Fresh pasture is an excellent source of both, but hay loses vitamin E rapidly after cutting. Consider supplementation if your weanling is stabled or on older hay for extended periods. Vitamin D is usually adequate if the weanling has access to sunlight or sun-cured hay.
Forage: The Cornerstone of the Weanling's Diet
Forage should form the foundation of every weanling's diet. As a general rule, weanlings should consume between 1.5% and 2% of their body weight in forage dry matter per day. For a 250 kg weanling, that translates to roughly 3.75-5 kg of dry matter, or approximately 4.5-6 kg of hay as fed (depending on moisture content).
Choosing the Right Forage
Not all forages are created equal for weanlings.
- Good-quality grass hay is a safe staple. Look for hay that is leafy, free from dust and mould, and ideally cut at an early stage of maturity for higher digestibility.
- Alfalfa (lucerne) hay is an excellent addition because it provides higher protein, lysine, and calcium than most grass hays. Feeding alfalfa at 30-50% of the total forage ration is a common and effective strategy for weanlings.
- Straw is too low in energy, protein, and minerals to serve as a primary forage source for growing youngstock. Small amounts can be used for fibre, but it should never replace good-quality hay.
- Haylage or baleage can work well as long as it is properly fermented, free from spoilage, and its higher moisture content is accounted for when calculating intake.
Pasture
Good-quality pasture can meet a significant portion of a weanling's energy and protein needs during the growing season. However, pasture alone is rarely balanced in minerals — particularly copper, zinc, and sometimes selenium. Even weanlings on lush pasture typically need a mineral supplement or a well-formulated concentrate feed to fill nutritional gaps.
Also be cautious of very lush, high-sugar pastures in spring and autumn, which can contribute excessive energy and trigger rapid, uneven growth spurts.
Concentrate Feeds for Weanlings
Most weanlings benefit from a concentrate feed designed specifically for growing horses. These feeds are formulated to complement forage and provide the additional energy, protein, vitamins, and minerals that forage alone cannot deliver.
What to Look For in a Weanling Feed
- Specifically labelled for youngstock or growing horses. Adult horse feeds and general purpose mixes are not formulated with the mineral ratios weanlings need.
- Moderate starch and sugar levels. Combined starch and sugar (NSC) should ideally be below 25-30% of the concentrate. High-starch feeds increase the risk of DOD and digestive upset.
- Adequate copper, zinc, and other trace minerals. Check the guaranteed analysis. If copper is listed below 40 ppm in the feed, it may not provide enough when fed at the recommended rate.
- Quality protein sources. Soybean meal, alfalfa meal, and other high-lysine ingredients are preferable to cereal-based protein.
Feeding Rate Matters
This is a critical point that many owners overlook. Concentrate feeds are formulated to deliver the correct nutrient levels at a specific feeding rate. If the bag says to feed 2-3 kg per day for a weanling, but you only feed 1 kg, you are not providing half the nutrition — you are providing the correct calories but only a fraction of the minerals and vitamins. This is one of the most common causes of mineral deficiency in well-meaning owners.
If your weanling does not need the full recommended amount of concentrate for energy reasons (perhaps it is an easy keeper or on excellent pasture), consider using a ration balancer or a concentrated supplement designed to fill the mineral and vitamin gap without adding excess calories.
Common Mistakes When Feeding Weanlings
1. Overfeeding for Rapid Growth
Pushing a weanling to grow as fast as possible — whether for the show ring or impatience — is one of the most damaging things you can do. Rapid growth places enormous stress on developing joints and cartilage. Aim for a steady growth curve, not a steep one.
2. Ignoring Mineral Balance
Feeding a generic supplement on top of an unanalysed forage is a gamble. High iron in hay can block copper absorption. Excess calcium without proportional phosphorus creates its own problems. The only way to know what your forage provides — and what it lacks — is to have it tested.
This is where analysing your horse's diet becomes invaluable. By understanding exactly what your forage delivers, you can tailor the concentrate and supplement programme to fill genuine gaps rather than guessing.
3. Feeding Adult Horse Feeds
All-purpose or adult maintenance feeds do not contain the elevated levels of calcium, copper, zinc, and lysine that a weanling's diet requires. Always use a feed specifically formulated for youngstock.
4. Restricting Forage
Weanlings should have near-constant access to forage. Restricting hay or pasture access can lead to gastric ulcers, stereotypic behaviours (such as cribbing and wood chewing), poor gut development, and inadequate fibre intake.
5. Abrupt Dietary Changes at Weaning
The stress of weaning itself is enough to cause digestive upset. If the foal was receiving creep feed before weaning, continue it. Introduce any new feeds gradually over 10-14 days to allow the gut microbiome to adapt.
Feeding Schedule and Practical Tips
Meal Size and Frequency
A weanling's stomach is still relatively small. Divide the daily concentrate ration into two or three meals rather than one large feed. This improves digestion, reduces the risk of hindgut acidosis, and keeps blood sugar levels more stable.
Fresh Water and Salt
Ensure clean, fresh water is available at all times. A salt block or loose salt should also be provided, as forage and concentrate feeds rarely supply adequate sodium and chloride.
Body Condition Monitoring
Learn to body condition score your weanling regularly. You should be able to feel the ribs easily without pressing hard, but they should not be visually prominent. A score of around 5 on the 1-9 Henneke scale is ideal. Adjust feed amounts based on condition rather than sticking rigidly to a set amount.
Growth Monitoring
Weighing your weanling regularly — ideally every two to four weeks — using a livestock scale or a well-calibrated weight tape, helps you track growth rate and catch problems early. Sudden growth spurts or plateaus may warrant a diet review.
Special Considerations
Breed Differences
Larger breeds (warmbloods, draught crosses) grow more slowly and reach maturity later, but their absolute nutrient requirements are higher. Thoroughbreds and other early-maturing breeds may reach a higher percentage of mature weight by weaning but can be more susceptible to DOD. Pony breeds and native types are generally easier keepers and may need less concentrate, but their mineral needs per kilogram of body weight are just as significant.
Weanlings with DOD Concerns
If your weanling shows signs of joint effusion, angular limb deformities, or has been diagnosed with OCD, work with your veterinarian and an equine nutritionist to review the diet immediately. Reducing energy intake (especially starch), ensuring adequate copper and zinc, and correcting any mineral imbalances is the first line of nutritional management.
Winter Feeding
Weanlings going through their first winter face increased energy demands for thermoregulation. Increase forage (which generates heat through fermentation in the hindgut) before increasing concentrates. Make sure vitamin E supplementation is in place, as conserved forage is typically low in this nutrient.
Summary: A Weanling Feeding Checklist
- Forage first: 1.5-2% of body weight in forage dry matter, with near-constant access.
- Quality protein: 14-16% crude protein in the total diet, with adequate lysine (30-35 g/day).
- Balanced minerals: Correct calcium:phosphorus ratio (1.5-2:1), adequate copper (75-100 mg/day), zinc (300-400 mg/day), and selenium.
- Moderate energy: Avoid high-starch feeds. Target steady, moderate growth.
- Youngstock-specific feed: Never substitute adult horse feeds.
- Feed at recommended rates: Or use a ration balancer if feeding below the recommended amount.
- Monitor body condition and growth: Adjust the diet as the weanling develops.
- Analyse your forage: Test hay and pasture so you can fill genuine nutritional gaps rather than guessing.
Feeding the weanling well is not about spending the most money or offering the fanciest feed. It is about understanding what a growing horse truly needs and delivering it consistently, in balance, and at the right rate. The effort you invest now will pay dividends for the rest of your horse's life.