Managing Horses in Summer

Managing Horses in Summer

It is the beginning of Summer and today is hot!  This Summer is going to be a scorcher, so along with the ongoing drought and threat of bushfires, dealing with extreme heat is going to be another concern for horse owners.   Prolonged exposure to high temperatures can result in heat stress, heat stroke and issues such as dehydration, colic and muscle spasms.
 
To help avoid the above issues here a few management strategies to consider.  Obviously, horses must have access to adequate shade to provide relief from the sun and if a horse is stabled, fans and mist are a great way to help keep them cool.  The horse’s work-load should be slowed down with work taking place in the cooler parts of the day if possible.   Make sure that tack is removed as soon as the ride is finished and hose the horse down on completion.  Clipping horses that have a long hairy coat is also a great help to keep them cool.  Along with these tips, the following is an example of what can be done nutritionally to help horses through the heat of summer.
 
Provide unlimited access to fresh, clean, palatable water.  This one is absolutely crucial as water is the number one absolute most essential nutrient.  With hard exercise and hot weather horses can drink around 10-15 litres/100kg of bodyweight daily (that’s around 75 L for a 500kg horse).  If dams/creeks have run dry this will mean that troughs and buckets have to be constantly filled and cleaned.  When a horse is stabled, make sure that they have a few large buckets filled, this is especially important on hot days and for horses that love to play with anything and everything.
 
There is also nothing worse than going to an event and finding out that your horse won’t drink.  If you have a horse that goes off water while away there are a few things you can do to encourage them to drink such as taking your own water from home, adding flavouring to the water (apple juice, cordial, molasses - find out what flavour your horse prefers), adding a bit of grain/apples/carrots to the water or adding electrolytes.  Remember you need to determine what works for your horse at home prior to leaving and if you are adding anything to the water then it will have to be cleaned even more regularly.  It’s recommended that you provide a second water bucket without anything added to it.
 
Another way to increase a horse’s water intake on a daily basis is by providing a diet high in fibre as fibre loves to hold water.  Using ingredients like copra meal, soy hulls and sugar beet pulp that swell up when they are soaked is a great way to provide a small internal reservoir of water for the horse to draw on when it is needed.  Add any supplements to the soaked feed just prior to feeding and don’t leave to soak for long periods especially in hot temperatures where they can quickly spoil.
 
This brings the topic to salt.  When it is hot horses need to sweat to prevent their bodies from dangerously overheating.  Water and electrolytes including sodium, chloride, potassium, magnesium and calcium are all lost from the body through sweat.  For effective sweating to occur a horse needs to be well hydrated and have a good supply of electrolytes in its body.  Salt (NaCl) is composed of sodium and chloride and they are the most commonly deficient electrolytes in a horse’s diet. Unfortunately, very few forages contain enough sodium to sufficiently meet maintenance requirements.  So, along with a good quality vitamin and mineral supplement (MegaMin Equine Enhancer) to balance shortfalls in pasture, it’s also recommended that free choice plain salt is also provided as horses will actively seek salt when they need it.  Many equine nutritionists prefer using loose rock salt to a salt block as it is cheaper, plus it is difficult for a horse to lick enough of a hard block to fill high requirements.  Using a commercial electrolyte supplement when horses are away from home, competing and working a lot harder, longer and sweating more than usual is valuable.  According to (Richards, 2019) a well formulated electrolyte supplement will contain 43-48% chloride, 20-25% sodium, 10-12% potassium and smaller amounts (usually 1-2%) of calcium and magnesium.  They also shouldn’t be filled with glucose or other fillers.
 
Watch for horses that don’t sweat, as your horse could be suffering from a serious condition called Anhydrosis.  Horses rely on being able to sweat to cool themselves down and if they don’t have the ability to sweat, they find it very difficult to stay cool.  You might notice these horses “puffing” as they resort to offloading heat via their lungs by breathing faster and harder.  These horses are at serious risk of hyperthermia (signs of heat stroke below) and veterinary advice should be sought.
 
Try to avoid diets that contain very excessive levels of protein as during the process of digestion and metabolism of protein a lot of heat is generated.  However, keep in mind that during drought conditions when forage quality is poor there is often a significant protein deficiency, so it is important that protein and in particularly essential amino acid requirements are being met.
 
It is usually recommended that horses have a diet that is high in forage but when the fibre is fermented in the hindgut a lot of heat is produced which in turn increases the amount of heat that the horse needs to get rid of to keep its body temperature normal.  So, for horses that are in significant work in hotter climates then a lower forage diet may be warranted.  However, it is still essential that horses receive a minimum of 1.5% of their bodyweight in forage on a daily basis.  Adding oil (best option as it produces the least heat) or cooked grain to the diet will help meet the horse’s energy requirements.  Don’t feed raw grain as this will once again lead to a lot of fermentation and heat production in the hindgut.
 
Make sure you are aware of the signs of heat stress:

  • Rectal temperature above 39°C
  • Increased breathing rate
  • Increased heart rate
  • Tiredness
  • Profuse sweating
  • Dehydration
  • Droopy ears
  • Reduced feed intake
  • A skin tent lasting several seconds after pinching the skin of the neck or shoulders

Heat stroke is an emergency and is a serious overheating condition in horses, which may occur from being worked hard in extreme heat and/or humidity.  Signs of heat stroke include:

  • Rectal temperature above 41°C
  • Rapid heart (more than 60 beats/min) and breath rates (more than 40) that don’t decline within 20 minutes of stopping exercise
  • Dehydration with dry mucous membranes and prolonged skin tents of 4-10 seconds
  • Distress (whinnying)
  • Muscle weakness
  • Incoordination
  • Collapse

If you suspect your horse is suffering from heat stroke contact your veterinarian immediately and get your horse into a cooler environment.
 
Shannon Godwin.
BAppSc GDTL

References

Johnston, J. (2019, November 10). 10 Hot Weather Horse Care Tips. Retrieved from The Horse: https://thehorse.com/117663/10-hot-weather-horse-care-tips/

Martinson, K. (2018, November 15). Caring for horses during hot weather. Retrieved from University of Minnesota Extension: https://extension.umn.edu/horse-care-and-management/caring-horses-during-hot-weather

Richards, N. (2019, October 30). Does Your Horse Need Electrolytes? Retrieved from FeedXL: https://feedxl.com/40-electrolytes/