190 DOMESTICATED ANIMALS AND PLANTS 
and the scrub costs something, so that the increased cost of 
giving a calf half the advantage of pure breeding cannot be over 
a dollar apiece in a herd of this size. Moreover, this dollar is 
not on the calf but rather on the mature animal.! 
Any way it is estimated, the great fact is, that by the system 
of grading, a single parent will give to every one of the young of 
the herd half the advantage of pure breeding in the first genera- 
tion. When, however, these half bloods reach breeding age, 
their offspring from a pure-bred sire will be not half bloods but 
three-quarter bloods, and their offspring will be seven eighths, 
and so on indefinitely, according to the following table : 
RATE OF IMPROVEMENT BY THE SYSTEM OF GRADING 
Generation Sire Dam Offspring eee 
I Pure Scrub 4 blood 50. 
2 Pure 4 blood 4 blood 75: 
3 Pure 4 blood } blood 87.5 
4 Pure } blood 43 blood 93-75 
5 Pure 43 blood 31 blood 96.875 
By this we see that after five generations of grading the 
offspring have attained thirty-one thirty-seconds, or nearly 
97 per cent, of the improvement that is possible by the use 
of pure blood, and all by the use of a single animal only at 
any given time. By this we see, too, that the sire alone can 
in time accomplish practically as much improvement as sire 
and dam could both accomplish at once, and all at an expense 
vastly less. 
Too much cannot be said in favor of improvement by grad- 
ing. It is safe, cheap, and sure, and, moreover, it does not dis- 
turb the affairs of the farmer. It means only the initial cost of 
a well-bred sire, and after that the improvement of the herd will 
take care of itself ; whereas, with scrub parents on both sides, no 
1 Of course, if the herd is being used for dairy purposes, only half the calves 
would be utilized, which would double the cost. 
