Horse Health
Hot Weather Facts
Help Your Horse Survive Summer
The hot summer months can be hard on horses. Training and
riding becomes more stressful and time in the pasture becomes more
uncomfortable. For horse owners in the hot, humid south this can be a
significant problem. Owners need to prepare their facilities to provide
the best relief possible. In addition, there are several heat related
illnesses that horse owners need to be aware of and try to prevent.
Heat stress results from multiple factors which work together to create
a serious health risk.
- The first factor in heat stress is the ambient temperature. As the summer heats up so do the horses. The increase in ambient temperature hinders the horse’s ability to get rid of excess heat. This is escalated significantly by the inability of the horse to loose heat at night because of humidity. In arid climates ambient daytime temperature is lost in the cool, dry night not causing the same scenario.
- The second factor, high humidity, further hinders cooling by slowing the evaporation of sweat.
- The third factor, calm conditions or lack of moving air, also slows the evaporation of sweat, prevents convection and therefore slows cooling.
- The fourth factor, heat generated by metabolism, which is affected by the type and amount of feed the horse receives, must also be dissipated and therefore increases heat stress.
Take these four factors and add in some riding and the increase in body heat produced and you compound the problem even more.
Protecting horses from heat stress begins with environmental
modification. The extent of modification possible will vary depending
on the farm setting and the number of horses.
- Fresh clean water and access to salt, always a must, becomes extremely important during the summer to off set the losses of body water through sweat.
- Plenty of shade, natural or man made, will provide substantial relief from heat stress.
- The addition of fans to stalls and run-in-sheds increases cooling by helping sweat evaporate and improving convection cooling.
Keeping horses in stalls can be the right answer depending on the barn and the temperament of the horse. Some barns are far hotter than an outdoor run-in-shed and not all horses do well being kept in a stall.
Feed alterations may also be appropriate during periods of heat stress. Feeding high fiber diets, especially poor quality fiber that is hard to digest, greatly increases internal heat production. The same can be said for diets with excessive protein concentration. High fat diets on the other hand provide more energy in a smaller volume and produce less heat during digestion.
Providing opportunities to cool off during riding will help avoid heat related problems. Simply wetting the horse and scraping dry will cool a horse rapidly. The key to hosing a horse is removing all excess water from the hair. Water left on the horse will act as insulation and slow down the cooling process. Cooling sheets and finding shade when possible will help. Access to fresh water is vital. Horses must be able to keep themselves hydrated to fight off heat stress.
More serious illnesses can develop from prolonged exposure to, or, excessive exercise in hot humid conditions.
Heat stroke develops when:
- The horse is producing more heat through metabolism and
external factors than
it can dissipate. - Heat stroke can be brought on by exercise, confinement in
hot stalls or trailers with
poor air flow. - Clinical signs can be seen as weakness, depression, colic, convulsions and, sometimes, death.
- Rectal temperatures are frequently above 105 - 106 degrees.
Heat exhaustion has similar signs to heat
stroke. Heat exhaustion occurs when
the horse’s fluid and energy reserves become depleted through
excessive sweating and exercise. Treatment of these diseases can be
successful if the signs are noticed early enough.
Another common problem during hot weather is Anhidrosis. Anhidrosis occurs when a horse stops sweating or the amount of sweat produced is significantly decreased. This condition usually develops gradually but can have a rapid onset in horses that have some other stress that is present, such as Influenza, pneumonia, COPD, etc. This is a very common condition in horses with COPD. Without the ability to sweat horses can not cool themselves which can result in heat exhaustion or stroke. This condition can be difficult to treat but many cases respond to supplements and minimizing heat stress by moving the horse to a dryer climate.
By taking some precautions and providing some protection from the summer heat most horses can handle the hot humid climate with minimal difficulty.