284 IOWA DEPARTMENT OF AGRICULTURE 
without any record ever being made as to his purchaser and he was 
never transferred on the records of the Jersey Club. His remarkable 
breeding value was recognized when it was too late and now we would like 
the chance of giving $1,000.00 to have him back. 
Minnette's Pedro is the last herd bull that has a sufficient number of 
daughters to give figures of any value. It may be observed that the 
herd remained practically at a standstill while he was at its head. In 
general this bull was not a very prepotent bull since we have wide 
variations and a lack of uniformity in his offspring. Among them are 
some excellent cows and some worthless. From the good dams we se- 
cured good daughters; from inferior dams the same quality of daughters. 
These figures show the immense difference in the way dairy qualities 
are transmitted even while all are pure bred animals. The selection ofi 
a herd bull is a very serious matter for the man who is trying to build 
up his herd and increase the average production. The more valuable 
the herd and the higher developed they are in the scale of dairy pro- 
duction, the more serious is the problem. 
One of the chief difficulties is that practically nothing can be predi- 
cated from the looks of the animal, if he has the inherent characteristics 
of transmitting good dairy qualities or not. Who will undertake to judge 
by the appearance of a bull if he is one that will transmit dairy qual- 
ities as did Missouri Rioter 3d or whether he is as worthless as Hugor- 
otus? The man who will discover some means of so judging will confer 
a benefit on breeders that can scarcely be estimated. 
There are two principles that are especially concerned with breeding 
and should be kept in mind. The first is that "Like produced like," and 
the second is the law of "natural variations." 
The cow in the condition nature made her undoubtedly produced only 
milk enough to feed the calf a few months until it could subsist on 
other foods. This milking characteristic was transmitted quite regular- 
ly. It was a case where like generally produced like but some cows 
even then were undoubtedly better milkers than others, due to the 
law of natural variation. The principles of selection did not come in to 
retain this variation and no improvement in this characteristic was 
made. 
After cattle were domesticated the same conditions existed but finally 
man began taking advantage of the natural variation and began saving 
breeding stock from those having the characteristics, such as greater 
milk production, which he found to be valuable. 
The animal which is different from others of its kind by natural 
variation will reproduce this characteristic in a certain proportion of its 
descendants. If this same natural variation is in the ancestry of both 
parents, the chance of transmission is much greater but under any cir- 
cumstances only a part of the progeny will have the new characteristic. 
The dairy cow of today is largely an artificial product or perhaps it 
would be better to say she is an abnormality since her mammary glands 
have been abnormally developed by taking advantage of the law of natural 
variations. 
The rule of "like produces like" is only true to a limited extent and 
the farther we get away from the original type in breeding the smaller 
