On the heels of the recent heat wave, no one needs a reminder that it has been HOT and HUMID the last few weeks. So, I’m going to jump right into signs of heat stress and how to avoid heat-stressed animals!
A quick note to begin with: don’t overlook humidity! While the temperature may seem mild, high relative humidity can and will still contribute to heat stress much more quickly than you realize.
Cattle
Temperatures start to work their way above a cow’s comfort zone at about 70 degrees. Much above this and we need to be thinking about some heat abatement strategies.
- Avoid activity as much as possible during the heat of the day. Move, work, or handle cattle early in the morning or late in the evening.
- Make sure there is access to plenty of water. The shorter the distance the cattle have to walk to water, the better.
- Avoid large groups of cattle in one place. Do not pen cattle together without plenty of room in between to dissipate heat, and make sure they can all find a shady spot in the pasture (or barn) without having to group together too much.
Monitoring your cattle is key to making sure they are handling the heat well. Look for signs such as rapid breathing, open-mouth breathing, panting, and drooling. Cattle showing these signs will need to be cooled off quickly. In more serious cases, trembling and loss of coordination can occur.
Horses
In a pasture situation, the same heat abatement strategies will apply to horses. Where we really need to be careful is when it comes to riding and exercise. In hot, humid weather, it only takes 17 minutes of moderate-intensity exercise to raise a horse’s body temperature to dangerous levels. When deciding whether or not to exercise your horse, use this formula
Air Temperature (°F) + Relative Humidity (%)
If the total is 130 or less, you’re good to go and your horse should be able to cool itself down. The higher over 130 the number gets, the harder it will be for your horse to cool itself down. It is recommended that you avoid exercising your horse when the number reaches 150 or above.
Signs of an overheated horse include rapid breathing, flared nostrils, profuse sweating, unpredictable behavior and gait, and a very high body temperature. To cool off an overheated horse, spray the head, back, neck, rump, and legs with a steady stream of cool water. Continue this until the horse is cooled back down.
Small Ruminants
Though they may be a little more tolerant to heat than cattle and horses, the same recommendations and heat stress symptoms apply to sheep and goats as cattle. If you have wool sheep, do not sheer them in the heat of the summer. Wool works as a natural insulator to keep sheep from getting too hot or too cold. A close sheer in the summer can limit moisture absorption and will allow more solar radiation.
Again, take into consideration the relative humidity when thinking about heat stress in your animals. In more serious cases (an uncoordinated, trembling cow or a horse with an extremely high rectal temperature for example) heat stress should be treated as an emergency and a veterinarian should be called.
Something to keep in mind when it comes to heat stress, an ounce of prevention is worth a pound of cure.
