GENETICS: W. E. CASTLE 
429 
further on the Bowlker farm, arrangements have been made for turning 
the entire project over to the University of Illinois, where experts in 
dairying and genetics will study the results in hand and such as may be 
forthcoming. At the generous suggestion of the new owners of the herd 
I am making this preHminary statement of results obtained at the 
Bowlker farm. 
Throughout the experiment the herd has been under the same system 
of management and in charge of the same superintendent, Mr. Leon 
Haley. The care and feeding have been such as are given to ordinary 
farm herds and the cows have been milked twice a day. Pure breds 
and crossbreds have been kept in the same barn and treated alike in 
every respect. The milk from each cow has been weighed at each milk- 
ing and these records are now available for study. Occasional butter- 
fat tests have been made for each cow but these are fewer than could be 
wished and make it possible only approximately to estimate the total 
butter fat production of each cow. 
Both the Fi and the F2 cross-bred calves have proved vigorous and 
have grown well. Some data have been accumulated on the relative 
growth-rates of the pure-bred and the cross-bred calves but these are 
insufficient as yet to lead to any definite conclusions. It should be 
observed, however, that the Fi cows have calved for the first time at a 
slightly earlier age than the cows of either pure breed kept on the farm, 
a bit of indirect evidence that in vigor and early maturity they con- 
form to the usually high standard of cross-breds. The recorded observa- 
tions on weight of milk given by pure bred and by Fi cows and the esti- 
mated amounts of butter-fat contained in this milk are summarized in 
tables 1, 2 and 3. Only data for comparable ages and lactation periods 
(first and second) are included in the tables. The column 'age' shows 
the approximate age of the cow at the beginning of the lactation period. 
The column 'time' shows the duration in months of the lactation period. 
If no entry is made in this column it will be understood that the lactation 
period covered a full year. The column 'total pounds milk' shows the 
amount of milk produced during the twelve months or less of the lacta- 
tion period. No account is made in this summary of milk produced 
after the cow had been in lactation for more than twelve months. 
Table 2 shows that 25 pure-bred registered liolsteins calving at an 
average age of 2.8 years gave in their first lactation period an average of 
7673 pounds of milk. The amount of butter-fat in the milk can be 
stated for only 8 of the 25 cows those which were still in the herd when 
the systematic taking of butter-fat tests for individual cows was under- 
taken. For these 8 cows the estimated butter-fat percentage is 3.4. 
