Page 65 - July 2020

tion. Pinching skin on the neck is not a reli- able indicator of dehydration. Thin and/or fit horses have little subcutaneous fat and so the skin on the neck can remain tented even in a well-hydrated individual. The point
of the shoulder and the upper eyelid more
consistently reveal true skin turgor.
• Rectal temperature: Normal rectal tem-
perature at rest runs less than 101 degrees Fahrenheit in an adult horse. Exercise may normally elevate rectal temperature to 101- 103 degrees Fahrenheit. A horse with a rectal temperature over 103.5 degrees Fahrenheit needs to be managed with cooling tech- niques. Once exercise is stopped, rectal temperature should decline steadily over 15 to 20 minutes. Rectal temperature exceed- ing 105 degrees Fahrenheit is dangerous, requiring immediate and aggressive cooling measures. At 106 degrees, kidney, liver, and brain damage can result. Rectal tempera- tures greater than 107 degrees may lead to convulsions, coma, or death.
COOLING TECHNIQUES
Many horses need assistance with cooling during and after workouts, especially in the summer months. Warm air temperature, espe- cially coupled with high humidity, can prevent a horse from adequately dissipating internal heat from his body while exercising. Heat stress generally develops due to overexertion, leading
to overheating rather than to external heating by the sun’s rays.
There are a variety of simple cooling strategies to use. While implementing these techniques, continue to monitor how well your horse is doing with intermittent assessment of vital signs and heart rate recovery.
• As a workout winds up, slow the horse to a
walk for 5-10 minutes. The rider should hop off, remove the saddle and keep the horse walking so blood flow continues to flush metabolic waste products and heat from
his muscles. Bringing a horse to a sudden and complete standstill after moderate to strenuous exercise causes blood to pool in the muscles. This compromises the circulat- ing blood volume, contributing to relative dehydration while being counterproductive to cooling.
• Copiously bathe the horse’s head, neck, armpits and legs with cool water. Large blood vessels in these locations flush heat to the skin surface, and repeated soaking facilitates evaporative cooling. While the horse is walking, he can be sponged and soaked, and this can continue once he is finally stopped to rest.
• Continuously apply and scrape water away until the horse’s skin feels cool to touch. Don’t be tempted to drape wet towels over the head and neck and leave them in place. Towels act as an insulator, thereby limiting cooling.
• Heat normally radiates from the head to keep the brain cooler than the inner core temperature of the body; increase in heat to the brain contributes to central or mental fatigue. Bathe the head as well as large blood vessels of the neck (jugular veins and carotid arteries) and legs to facilitate movement of heat out of the central body core.
• Cooling a horse down too rapidly can cause chilling or muscle cramps (tying-up, myositis). In hot and humid climates, ice water may be applied to the entire body with less risk of muscle cramping. How- ever, ice water baths in more arid climates may cause problems in large muscle groups – blood vessels constrict away from the surface while retaining metabolic byprod- ucts and heat that need to be carried out from muscle depths. Besides exhibiting poor metabolic recoveries, the horse might develop “tying up” syndrome with painful muscle spasms. In arid climates, it is best to confine cooling baths only to areas in front of the withers.
• Monitor rectal temperature and muscle tone of the haunches as the horse is cooled down. Once rectal temperature reaches 101 degrees Fahrenheit and/or the chest feels cool to touch, cooling assistance can be paused or stopped.
• Offer drinking water following exercise. For horses that have been exercised at gal- lops or sprints, initially only offer small, frequent drinks. In contrast, horses work- ing at steady aerobic paces can drink what they want.
• Shade is important to improve comfort and cooling. Find an area with good air circula- tion, preferably with a light breeze. Fans provide convective cooling – air flowing across the horse’s body pulls heat from the skin. Periodic, short walks help muscles pump heat away from deeper tissues.
If you see any abnormal signs (as described above) or if a horse isn’t cooling down appropri- ately within 15 minutes, contact your veterinar- ian immediately.
VETERINARY VIEWS
There are a variety of simple cooling strategies to use, including:
Continuously apply and scrape water away until the horse’s Bathing the horse’s head, neck, armpits and legs with cool water. skin feels cool to the touch.
Some vital signs you should check to determine how well your horse is coping with the exercise demand and climate conditions of the day are:
Heart rate Gum color and capillary refill time
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