182 The Diseases of Animals 
are castrated on account of disease, to prevent them 
from breeding, to make them more tractable, to cause 
them to fatten more easily; and in some animals to 
improve the quality of the meat. 
In general, the younger the animals when operated 
the better they withstand the operation. Colts are 
usually castrated the spring they are two years old, but, 
if they are not well developed, it is sometimes better to 
let them go until they are three vears old. Calves, 
lambs and pigs are usually castrated when a few 
weeks old, or as soon as they are growing nicely. 
Heifers are spayed as yearlings or two-year-olds; 
sows and bitches at any age after three months. 
Females should not be spayed when pregnant, or in 
heat. Animals should not be operated when sick 
or debilitated. Operating when the weather is very 
hot or very cold, or when the flies are bad, should 
be avoided. The spring of the year, when the weather 
is cool and pasture good, is an excellent time. 
Before operating, the animals should always be 
examined to determine whether both testicles are 
“down,” that is, in the serotum, not in the abdominal 
eavity, and to determine, also, whether there is a hernia 
or rupture into the scrotum. (Page 179.) Colts with 
testicles not down are called “ridglings,” or “eryptor- 
chids.” (Page 186.) Hernias are more likely to be 
found in colts and pigs. 
In castrating, the greatest danger to be guarded against 
is hemorrhage. In small animals this is inconsiderable; 
in larger animals measures must be taken to prevent 
this, as the artery that supplies the testicle is large. 
