When it comes to feeding a mare, the most important thing to understand is that her nutritional needs change significantly depending on her reproductive status, age, and workload. A mare that is pregnant, lactating, or in heavy work requires more energy and specific nutrients than a maintenance or idle mare. Our editorial team emphasizes that a mare’s diet should always be based on high quality forage, such as grass hay or pasture, with concentrates added only to meet additional requirements.
Mares are hindgut fermenters, meaning they digest fiber in the cecum and colon. This makes a steady supply of forage critical to their digestive health. Overfeeding grain or rich feeds can lead to colic, laminitis, or metabolic issues. The foundation of any mare’s diet is clean, mold free hay or fresh pasture, supplemented with a balanced vitamin and mineral mix if needed. Always provide fresh, clean water and a salt block.
Forage: The Foundation of a Mare's Diet
Forage, whether pasture grass or hay, should make up the majority of a mare’s diet. Mares evolved to graze for up to 16 hours a day, so providing free choice hay or ample pasture mimics their natural feeding behavior. Good quality grass hay, such as timothy, orchard grass, or brome, is ideal for most mares. Legume hays like alfalfa are higher in protein and calcium, which can be beneficial for lactating mares but may be too rich for idle mares, potentially causing weight gain or metabolic issues.
Mares should consume roughly 1.5 to 2.5% of their body weight in forage daily. For a 1,200 pound mare, that is about 18 to 30 pounds of hay per day. Pasture grazing can reduce hay needs, but be cautious of lush spring grass that is high in non structural carbohydrates, which can trigger laminitis in susceptible mares. In winter or when pasture is poor, hay is the primary forage source.
Concentrates and Supplements for Mares
Concentrates, such as grains or pelleted feeds, are used to fill nutritional gaps that forage alone cannot meet. This is especially important for pregnant and lactating mares, who have higher energy, protein, calcium, and phosphorus demands. A mare in the last trimester of pregnancy may need a feed formulated for broodmares, while a lactating mare requires even more calories and nutrients to support milk production. Working mares, such as those in light to moderate exercise, may also benefit from a balanced grain ration.
For idle or easy keeper mares, concentrates are often unnecessary and can lead to obesity. If supplements are used, they should be based on forage analysis to correct specific deficiencies. Common supplements include vitamin E and selenium for mares on hay lacking these nutrients, and a balanced mineral mix. Avoid over supplementing, as excess can be harmful. Always introduce grain gradually over a week to avoid digestive upset.
Feeding Schedules and Water Requirements
Mares should have access to forage at all times or be fed at least two to three times a day to maintain gut health and prevent ulcers. Grain meals should be split into two or more feedings to reduce the risk of colic and laminitis. A typical schedule might include hay in the morning and evening, with grain fed at the same times. Changes to the diet should be made slowly over 7 to 10 days to allow the hindgut microbes to adjust.
Water is critical: a mare drinks 5 to 10 gallons per day, more in hot weather or when lactating. Clean, unfrozen water must always be available. In winter, heated water buckets may be necessary to encourage adequate intake. Dehydration can lead to colic and impaction. Salt, either loose or as a block, should be offered free choice to encourage drinking and replace electrolytes lost in sweat.
Common Feeding Mistakes and Health Considerations
One common mistake is overfeeding grain relative to forage. This can cause obesity, which in mares is linked to insulin resistance, laminitis, and reduced fertility. Another mistake is feeding moldy or dusty hay, which can lead to respiratory issues or colic. Mares should also be kept at a healthy body condition score of 5 to 6 on a 9 point scale. Underweight mares may need more calories, while overweight mares require restricted energy from concentrates and possibly limited pasture turnout.
Pregnant mares should not be allowed to become obese or underweight, as both affect foal health and ease of foaling. Lactating mares need extra calcium and phosphorus, but these must be balanced. Always consult with an equine nutritionist or feed company representative to tailor the diet to your specific mare’s needs based on forage tests and body condition.