To detect problems before they happen or while they are still minor, it is important to understand your horses and their normal behavior. Spend some time every day watching them interact with their environment. Even taking five minutes a day will provide amazing amounts of insight into how they normally behave. If your horse gets ill, it will often act oddly. Odd behavior without reason is always worth investigating -- it could be the beginning signs of illness or injury.
To help you learn about your horses vital signs, ask your vet to show you how to take your horses heart rate, respiration rate and body temperature. Record your horse's normal vital signs during normal activities. Vital signs often change depending on whether your horse is working, eating, nervous or calm. While the chart of normal vital signs is a great place to start, the more information you have about your own horse's vital signs, the better.
In addition to watching your horses, you should groom your horse on a daily basis. If you are unable to groom them daily, make a schedule that allows you to touch and examine them at least once a week. Look for any obvious wounds or infections. Clean the hooves and look for any cuts or punctures in the hoof or leg.
If you are concerned about your horse's health, check its vital signs. Because a horse is a prey animal, they often do not show external signs of pain or distress (in nature, that could cause a predator decide to target them!) If your horse is in pain, it will be reflected in its vital signs. Your horse's body temperature, heart rate and respiration rate will shoot up. If that's the case, call your vet immediately!