278 Western Live-stock Management 
figure eleven months, and this is usually close enough. 
Mares vary greatly in the length of the period of gesta- 
tion. Some perfectly healthy foals may be dropped in 
less than ten months and others may be carried for twelve 
months. Usually, however, a variation of over two 
weeks is considered abnormal. 
Conditions affecting breeding. 
Some horse-men are successful in breeding mares at 
two years of age, but it is not customary to breed until 
three. When the mare is bred at two years of age she 
is usually allowed to skip the next year, and is fed very 
liberally. Otherwise the two-year-old mare will be 
stunted considerably in growth. The argument in favor of 
the early breeding is that it insures a more reliable breeder. 
This, however, has never been fully demonstrated. 
The breeding mare should not be overly. fat. A mare 
will breed better if she is in normal flesh than if she is 
pampered. A better plan is to have the mare increasing 
in flesh rather than decreasing at the time of breeding, 
if there is to be any variation one way or the other. If 
the mares have any sickness due to foaling, or any trouble 
with the sexual organs, they should not be bred until 
they have thoroughly recovered from the ailment. It is 
better to allow them rest until fall and breed them at that 
time than to run any unnecessary risks. If perfectly 
normal, the brood mare is generally bred at the ninth day 
after foaling, and if not bred at this time, she occasionally 
will not do so until the colt is weaned, although this is 
not usually the case. 
Serving the mare. 
The first item in serving the mare is to ascertain 
whether or not she is in heat. This is determined by 
