Summer care

The BHS points out that horses find it easier to warm up than to cool down. Summer care is mostly about water, shade and timing, and about knowing the signs that a horse is struggling.

Water

Horses drink more in hot weather. The BHS says a 500kg horse may drink 50–70 litres a day, or four to six buckets, and more if it's working. Too little water raises the risk of dehydration and impaction colic.

• Give more than one water source, away from field corners, so one horse can't keep others away. Larger containers may encourage drinking.
• Clean troughs and buckets regularly to stop algae and bacteria building up.
• A sweet flavour such as apple juice can tempt a reluctant drinker, but always offer plain water as well.
• Soaking hay adds water to the diet. In warm weather soak it for less time, to limit mould and bacteria, and remember soaking removes nutrients. Soaked feed is not a substitute for drinking water.

Signs of dehydration listed by the BHS include dark or less urine, very dry or fewer droppings, a higher heart rate, dullness, a dry mouth with thick saliva, dull or sunken eyes, dark gums and a slow capillary refill (press the gum: it takes longer than normal to turn pink again). One sign alone doesn't confirm it; the more signs, the more likely and severe it is. The BHS says the skin pinch test is not an accurate measure, and to call your vet if you're worried.

Shade and shelter

The BHS recommends shelter or shade in hot weather. A field shelter gives the best protection from sun and biting insects. Trees and hedges can do instead, but Bransby Horses points out that their shade moves with the sun, so there may be times of day when your horse can't reach it, and natural shelter may not keep insects off. Check that no tree or hedge is poisonous.

Stabling through the hottest part of the day is an option if the stable stays cool and well ventilated. A badly ventilated stable can become hot and stuffy, which is bad for a horse's body and mind. Make any change of routine gradually, to reduce the risk of colic.

Flies

Flies and biting insects are worse in hot weather. Bransby Horses notes they gather round the eyes and can make them sore and swollen, and some horses come up in lumps where they're bitten. To reduce them, the BHS and Bransby suggest:

• keeping your horse in during the day and out at night
• thin fly sheets and fly masks
• fly repellent used as the maker's instructions say, never on inflamed or broken skin
• picking up droppings often, in the field and the stable, and keeping the muck heap away from your horse

In very hot weather, a fly rug can stop a horse cooling down, so take it off or use a light-coloured, breathable one, with plenty of shelter. For horses with sweet itch, see skin and coat problems.

Sunburn

Horses with pink skin under grey or white hair burn most easily. The BHS strongly recommends sun protection for them, especially for pink noses.

Grass in summer

• Dried grass. Sun-dried grass still has calories, but less goodness, so a low-calorie balancer or vitamin and mineral supplement may be needed. A horse that isn't losing weight doesn't necessarily need extra forage; one in medium to hard work may need more calories. Horses burn fewer calories in summer than winter, so check workload and fat score first.
• Bare paddocks. Horses may eat more soil or sand, which raises the risk of colic. Extra forage can help; introduce any new forage over at least 10–14 days.
• Rain after sun. Grass grows fast, which raises the risk of laminitis for overweight horses and those with equine metabolic syndrome or Cushing's disease. Bransby Horses also warns that grass is higher in sugar through spring and summer. Control grazing (see spring care).

Poisonous plants

Ragwort flowers from May to October, says World Horse Welfare. If you have to pull it while it's flowering, wear a face mask as well as gloves, so you don't breathe in the pollen, and take every trace out of the field: dead ragwort is still poisonous. The BHS says foxgloves flower from June to September, and stay poisonous when dried, so don't leave pulled plants in the field. Check hay for both. Grass sickness is most common between April and June, says the BHS.

Exercise and travel in the heat

The BHS's advice to prevent heat illness:

• Work in the cooler parts of the day, at a lower intensity, with more breaks, and give your horse time to get used to rising temperatures.
• Offer fresh water and watch how much your horse drinks. Electrolytes may help a working horse replace the salts it sweats out; use a balanced product as the maker directs, and keep plain water available.
• Hot, humid weather is the riskiest, because sweat evaporates less easily.
• Overweight horses, and horses with a thick or long coat such as those with Cushing's disease, are at greater risk. Clipping a thick coat in the warmer months can help.
• Horses often drink less when travelling. On long journeys, stop every three to four hours and offer water. See travelling safely.

Heat exhaustion and heatstroke

A horse's normal temperature is about 37.5–38.5°C. The BHS says a temperature above 38.9°C should be checked by a vet, and above 40.5°C is a medical emergency.

Heat exhaustion often comes with dehydration, after long exposure or exercise in very hot or humid weather. Signs include fast, shallow breathing and flared nostrils, a temperature that stays high after rest, a raised or irregular heartbeat, too much or too little sweating, eating and drinking less, slow recovery after work, muscle spasms, dullness or irritability, and "thumps" (synchronous diaphragmatic flutter). Changes in behaviour may show before the physical signs.

Heatstroke is when the horse can no longer cool itself. It can appear suddenly, and signs include unsteadiness, confusion, aggression, collapse and seizures. It can damage the brain, heart, lungs, kidneys and muscles, and can kill.