When temperatures rise: Summer management for mares and foals

Summer is often considered the ideal season for young foals. Long days, turnout on pasture and warm temperatures create excellent conditions for growth and development. Yet periods of prolonged heat can place significant additional demands on both broodmares and foals, making careful management essential throughout the warmest months of the year.

For breeders, summer management extends far beyond providing shade and water. Heat affects hydration, milk production, fertility, respiratory health, pasture quality and even the immune function of young foals. During heatwaves, seemingly small management details can make a considerable difference.

Shade is essential, but so is ventilation

Access to shade is one of the most important requirements for mares and foals during hot weather. Natural shelter, trees and field shelters all help horses avoid prolonged exposure to direct sunlight.

However, shade alone is not always enough. Poorly ventilated shelters can quickly trap heat and become significantly warmer than the surrounding environment. This is particularly important for young foals, which often spend large portions of the day resting or sleeping.

A foal sleeping for extended periods in an overheated shelter may nurse less frequently and drink less, increasing the risk of dehydration during periods of extreme heat. Good airflow and ventilation are therefore just as important as protection from direct sunlight. Ideally, shelters should provide both shade and continuous air circulation. During periods of extreme heat, many breeders also adjust turnout schedules, allowing mares and foals greater access to pasture during the cooler morning and evening hours while avoiding the most intense heat of the day.

The lactating mare faces increased demands

Hot weather places considerable pressure on broodmares, particularly those nursing young foals. Lactation significantly increases water requirements, and during periods of extreme heat fluid losses through sweating rise dramatically.

Milk production depends heavily on hydration, nutritional intake and overall health. Reduced appetite, dehydration or declining body condition can all influence milk production, potentially affecting the foal's nutrient intake and development. Careful monitoring of both mare condition and foal growth is therefore particularly important throughout the summer months.

Fresh, clean water should always be available and checked regularly throughout the day. In hot weather, water quality can deteriorate quickly and consumption may increase substantially.

Heat stress and fertility

Summer heat can also influence reproductive management. High temperatures place additional physiological stress on broodmares and may negatively affect fertility, particularly when mares are already managing the demands of lactation.

Breeding mares during periods of extreme heat requires close attention to hydration, body condition and overall health status. Heat stress can impact normal reproductive function and may reduce the likelihood of optimal conception and embryo development. Maintaining mares in good condition and minimizing unnecessary stress becomes especially important during the breeding season.

Foals require extra attention during heatwaves

Healthy foals are generally resilient, but their ability to regulate body temperature is still developing. During prolonged heat, foals may become quieter, spend more time resting and nurse less frequently.

Daily observation remains one of the breeder's most valuable tools. Subtle changes in behaviour often provide the earliest indication that a foal may be struggling with heat stress, dehydration or illness. Particular attention should be paid to nursing frequency, activity levels and overall alertness. A foal that appears unusually lethargic, reluctant to nurse or less interested in its surroundings should never be ignored.

Dust, dry conditions and respiratory health

Dry summer conditions create another challenge: dust.

Dusty paddocks, dry turnout areas and heavily used fields can significantly increase respiratory irritation in both mares and foals. Young foals are especially vulnerable because their respiratory and immune systems are still developing.

Many breeders are particularly aware of the potential association between dusty environments and Rhodococcus equi, a bacterial disease that remains a concern on breeding farms worldwide. While no management system can completely eliminate risk, reducing dust exposure wherever possible remains an important preventive measure. Good pasture management, proper ventilation and avoiding excessively dusty environments can all contribute to healthier respiratory conditions for young foals.

Breeding farms with a history of Rhodococcus equi should be particularly vigilant during prolonged periods of dry weather, as dusty conditions may increase exposure risks for young foals. Reducing dust wherever possible and avoiding excessively dusty or sandy turnout areas remains an important part of preventative management.

When green pastures are no longer enough

One of the most common mistakes during summer is assuming that green fields automatically provide adequate nutrition.

During prolonged drought or extreme temperatures, pasture quality can decline significantly even when fields continue to appear visually attractive. Nutritional value, protein levels and overall forage quality may decrease, while lactating mares continue to have exceptionally high nutritional demands.

Regular monitoring of body condition remains essential. A mare supporting a growing foal can lose condition surprisingly quickly when pasture quality deteriorates. Supplemental forage and carefully balanced nutrition may become necessary long before the fields appear depleted.

Fields may continue to appear green despite significant declines in nutritional value, making regular assessment of mare condition more reliable than visual evaluation of pasture alone.

Observation remains the most valuable tool

While every breeding farm develops its own management routine, one principle remains universal: careful observation.

The most successful breeders are often those who notice small changes before they become larger problems. Monitoring mares, checking foals regularly, evaluating body condition and responding quickly to early signs of heat stress remain among the most effective ways to safeguard health throughout the summer.

Summer remains one of the most important periods in a young horse’s development. While warm weather creates excellent opportunities for growth, successful management relies on careful observation and attention to detail. From ventilation and hydration to nutrition and respiratory health, small adjustments can make a significant difference, helping mares and foals remain healthy, comfortable and able to thrive throughout even the hottest months of the year.