THE DAIRY BREEDS OF CATTLE 283 
and breeding purpose. It “is identified,’’ says Professor 
Hengerveld, “ with their use, lodging, feeding and manage- 
ment.” The tendency of breeding, in the United States, 
is altogether in the direction of milk form. 
The heifers mature rapidly, and, if well fed, are ready to 
breed at twelve to fifteen months of age. As a rule, they 
deliver their calves without difficulty and may be relied 
on to enter the dairy herd, productively, when two years 
old. 
316. Use for milk. — Freshening between two and three 
years old the heifers produce with first calf about three- 
fifths to three-fourths the quantity of milk produced by 
mature animals of the breed, and if liberally supplied with 
suitable food will produce 8000 to 10,000 pounds of milk 
inone year. They will continue their growth and increase 
in productiveness until four and one-half or five years old, 
at which age they will reach, if in good milking condition, 
an average weight of 1300 pounds. From this time 
forward average cows of the breed will produce when in 
full flow of milk fifty to seventy pounds of milk daily or 
12,000 to 14,000 pounds of milk a year until eleven or 
twelve years of age. Tests of over two thousand ani- 
mals of all ages for a lactation period not exceeding 365 
days show that the average per cent of fat is between 3.3 
and 3.5 and that the total solids average 12 per cent. In 
Holstein-Friesian milk the solids not fat, to the fat, aver- 
age one to two and one-half. That is, in average Holstein- 
Friesian milk for every pound of fat will be found not less 
than two and one-half pounds of solids not fat. 
To the close of the fiscal year 1914-15 on April 30, 
1915, 1992 Holstein-Friesian cows and heifers had com- 
pleted tests covering a lactation period of not exceeding 
365 days as follows: 707 full-aged cows averaged: milk, 
