212 
The cows that had reached maturity 
before coming to the station all de- 
clined in production after their first 
year even though getting better feed 
and care than they had been accus- 
tomed to previously. It can not be 
stated, however, that good feed made 
no improvement in their case as it is 
undoubtedly true that their records 
at the station were better than any 
they previously made under adverse 
conditions, but they were unable to 
increase in production during their 
later years at the station as advancing 
age brought about a decrease that could 
not be prevented by good feed and care. 
When the scrub cows that came to 
the station after reaching maturity 
are compared with those coming at 
four years of age and those coming 
before first freshening, it is noticed 
that those arriving at four years of age 
produced 14% more milk and 8% 
more fat, while those coming as heifers 
produced 27% more milk and 24% 
more fat than did the older animals. 
This shows that the younger an animal 
is when subjected to good treatment 
the greater is its response. 
In other words environmental con- 
ditions, or feeding and general care, 
have a considerable influence on the 
milk and butterfat production of cows, 
and the younger animals are when 
subjected to a certain set of conditions 
the more readily will they respond. 
USE OF SCRUB SIRE 
Records are available for three cows 
and their daughters by a scrub bull, 
and though this is too limited a number 
The Journal of Heredity 
upon which to base definite assertions, 
certain inferences are justified. Two 
of the dams were mature on reaching 
the station while the other was a four 
year old. Consequently, though the 
calves received good feed and care from 
birth, the dams were under favorable 
conditions for only a limited period of 
their lives. 
The heifers by the scrub bull pro- 
duced on the average 10% more milk 
and 13% more fat than did their dams, 
and considering that these heifers were 
grown out amid surroundings much 
more favorable than those which their 
dams were subjected to at a similar 
age, it must be assumed that the in- 
crease obtained was due, not to the 
scrub bull but to the feed and care the 
heifers received. 
A scrub bull will sire scrub offspring 
and no improvement in the production 
of a herd of milking cows can be 
obtained where such a sire is at the 
head of it. 
USE OF PURE BRED SIRES 
A number of grade animals sired by 
purebred bulls and descended from 
the scrub cows have now completed 
records. These will be studied in two 
groups—the first generation grades, or 
those carrying 50% of the blood of one 
of the recognized dairy breeds, and the 
second generation grades, or those 
carrying 75% of the blood of one of 
those breeds. The only way to deter- 
mine correctly the value of a bull is to 
compare the records of his daughters 
with those of their dams though there 
are difficulties connected even with 
PaBLe VI: Average for First Generation Grades and Their Scrub Dams 
Dams Daughters Increase in 
Production 
Group =| 
No. of|No. of} Milk Fat |No. of|No. of} Milk Fat Milk | Fat 
Cows |Lacta- Ibs. Ibs.. |Cows |Lacta-| Ibs. lbs. % % 
tions tions 
Holstein 4 19 3406.2 168.74) 4 18 6444.4) 265.92} 89 58 
Guernsey 6 35 4186.0 | 189.39) 7 20 4899.8} 240.96] 17 27 
Jersey 3 20 4046.7 194.11 3 9 4833.4} ~265.88|] 22 34 
Average 9 47 3968.6 185.66) 14 47 5497.8 Dhsloensva | arch!) 37 
