Learning how to recognize when your horse is not feeling well is an important skill to develop. Like humans, signs of illness can include any of the following: lack of appetite, lethargy, depression, fever, nasal discharge, diarrhea or constipation.
A sick horse may stand towards the back of its stall with its head down and ears not erect. It may appear depressed: less responsive to your voice and to other stimuli. Such horses may or may not be feverish (pyrexic); taking temperatures should be done to confirm the presence of fever. Some horses may refuse their grain but continue to pick at their ration of hay. Diarrhea if present can take several forms from pasty liquid to watery and projectile. Persistent "cow pie" manure is also abnormal. Within the herd, the sick horse frequently separates itself from the others and travels well behind the rest or fails to follow.
Examination of your horse's mucus membranes can also give you valuable information: the membranes lining the mouth, vulva and around the eyes should be pink in colour. Dark red to purple or greyish colouration suggests toxaemia; pale pink to white suggests anemia (blood loss is one reason) or shock; and yellowish/orange colour occurs with jaundice (liver dysfunction is one cause). After you depress the gums with your thumb and release, the colour should return to normal within 1-2 seconds. Prolongation of the blanched colour for 3 seconds or longer occurs with several conditions such as shock and dehydration.
If you have a stethoscope, ask your veterinarian to guide you in listening to the sounds that your horse's intestinal tract makes. These normal gurgling sounds, called borborygmus, can be heard on both sides of his flank. These sounds can decrease in quantity in some types of colic, and increase in others. Get to know what your horse sounds like when he is healthy!