The indications afforded by the clinical thermometer are valuable guides as to the state of the animal’s health at the time, or what it will shortly be. Thus, in a horse at rest under ordinary conditions, if there be a rise of three or four degrees without the animal evincing any other sign of illness, we may be assured that disease in some form will, after a day or two, manifest itself in him. During illness, a temperature of, say, 106° F. or more points to a condition of great danger.
The clinical thermometer is especially useful in indicating the state of an animal during infective diseases and diseases of the organs of breathing. A fall in temperature, when it has been abnormally high, will generally point to a favorable termination of the disease; although in some cases it is the precursor of rapidly approaching death.
TEMPERATURE DURING HEALTH.
As a rule, there is a daily variation in the internal temperature of a healthy animal of about 1° F.; the maximum being attained at about 6 o’clock in the evening. In the adult animal, the temperature is about 1° F. higher than in a very young or very old animal. It is about 1° F. less in the female than in the male, except when she is “in season,” during which time it is about 2° F. higher than normal. The temperature of well-bred animals is higher than that of common animals. A rise of 4° or 5° F., compatible with health, may be observed in animals during violent exercise or work in hot weather. The temperature of well-fed animals is higher than that of poorly-fed ones. During digestion, it rises about 1° F., and falls about the same amount during sleep. Exposure to the rays of a hot sun for a few hours may cause a rise of as much as 3° F., and the effects of cold and rain may equally lower it.
Normal Temperature of the Horse.—
From 2 to 5 years old the temperature is 100.6° F.
From 5 to 10 years old the temperature is 100.4° F.
From 10 to 15 years old the temperature is 100° F.
From 15 to 20 years old the temperature is 98.4° to 100.2° F.