McCandlish: Environment and Breeding 209 
_ THREE-QUARTER-BLOOD GUERNSEY NO. 236 OUT OF HALF-BLOOD GUERNSEY NO. 87 
The average production of this cow has been 6345.7 pounds of milk and 320.16 pounds of fat. 
“Records are now available on two generations of grades descended from the scrub cows, and one 
animal of the next generation has just entered the milking herd.” 
and the remainder were mature, that is 
they were over five years of age. The 
behavior of those three groups under 
improved conditions is of interest. 
The animals that were four years of 
age on reaching the station produced 
an average of 3,804.6 pounds of milk 
and 149.24 pounds of butterfat during 
their first lactation period, and with 
good care and liberal feeding they 
increased steadily in production until 
at seven years of age they were yielding 
4,907.7 pounds of milk and 229.91 
(Fig. 12.) 
pounds of butterfat, or 59% more milk 
and 54% more fat than they did during 
their first year at the station. An 
increase of only 10% in milk and 8% in 
fat yield was expected as the result 
of the maturing of the animals and 
consequently, the greater portion of 
the increase secured must be attributed 
to environmental factors. After seven 
years of age the decrease in production 
due to advancing age was quite notice- 
able—a condition which was expected. 
TABLE III: Production of Cows That Were Mature on Arrival at the Station 
Average Production Increase in Production 
Lactation Milk Fat Milk Fat 
No. Ibs. Ibs. % % 
1 3790.9 183.84 | 
I} 2874.0 133.50 —24 —27 
1 | 2841.1 141.60 | —25 23 
