Vol. 6, 1920 
GENETICS: R. PEARL 
231 
This table gives to the breeder information of a sort he has never had 
before. It enables him at once to form a real judgment of the worth of 
various bulls which appear in the pedigree of Jersey cattle. Many of the 
bulls in the minus side of the table have at different times been regarded 
as leaders of the breed and they and their progeny have sold for fabulous 
prices. With a scientific measure in hand of their actual effect upon the 
breed it will in the future be exceedingly difficult to persuade any intelli- 
gent breeder of the transcendent merits of these minus sires. On the 
theoretical side there are many interesting points which flow from this and 
similar tables, but space cannot be taken here for their discussion. 
After presenting the basic tables for milk production, fat percentage, 
and net fat, similar to table 1 here, the complete paper goes on to discuss 
various related problems, such as the relation of inbreeding, amount of 
Island bred stock, etc., to production. The chief results of the whole 
study may be stated as follows: 
1. There are 224 Jersey Registry of Merit sires which meet the require- 
ments of this performance test for their transmitting qualities in milk 
production. One hundred and five of these sires or less than one-half 
raise the milk production of their daughters over that of the dams of these 
daughters. The largest number of daughter-dam pairs is 39 for the sire 
Hood Farm Pogis 9th, 55552. Of those sires which have a large number 
of pairs. Hood Farm Torono 60326 with 34 pairs stands first in his trans- 
mitting qualities raising the milk production of his daughters on the 
average 2620.1 pounds. 
2. Two hundred and twenty -five sires are included in the table giving 
the sires which met the requirements of the daughter-dam performance 
test for transmitting qualities of butter-fat percentage. Out of this num- 
ber 101 sires raised the butter-fat percentage of their daughters' milk as 
compared with the butter-fat percentage of the dams of these daughters. 
The leading sire in this butter-fat percentage performance test was Clear 
Brook Chief 74685 raising his daughters on the average 1.338% of butter- 
fat. This sire had two daughter-dam pairs. Hood Farm Pogis 9th 
leads in number of daughter-dam pairs with 42. This bull raised the 
butter-fat percentage of his daughter on the average of 0.243% over the 
butter-fat percentage of the dams of their daughters. 
3. The sires mentioned as superior in the milk transmitting ability, 
Hood Farm Torono and Spermfield Owl, do not check up so well in their 
ability to transmit high butter-fat percentage. Hood Farm Torono 
caused his daughter on the average to be 0.225 per cent of butter-fat below 
what the dams of these daughters produced. Spermfield Owl only raised 
his daughters on the average 0.027% of butter-fat over what the dams of 
these daughters produced. 
4. There are 224 sires of known transmitting ability for net butter-fat. 
Of this number only 99 sires raise the butter-fat production of their 
