% OF a . 21.” ON A ese Saag 
Y* a ot ype a. ie ee 
at ae x hie) Pry & 
; x ‘4 Pe Er at F 
a2) Peryipe a 
ee : 
456 Report oF THE DIRECTOR OF THE 
Changes in Actual Number of Globules During Lactation. 
* During the first period of lactation of several of the animals 
it was found that there was an apparent and large increase in the 
actual number of globules, without regard to their size, found in 
the milk during the successive months of lactation. To deter- 
mine whether this apparent increase was a characteristic change 
going on during lactation the following experiment was made 
during the second period of lactation and with greater care 
to avoid any possible error which may have existed before. 
In the following tables the first gives the average number of 
milk globules in samples of milk of .0001 c. m. m. from each 
cow and for each month of lactation up to and including the 
twelfth month; also the average count for each breed per month, 
and a general average and ratio of all. It will be seen that the 
mumber of globules increases very steadily from the first to 
the last month, the increase being quite 150 per cent., although 
the difference in this increase is very marked between the several 
breeds, as for example the Jerseys and Guernseys as compared 
with the Ayrshires and Holstein-Friesians; and the study of 
this table will show characteristics and resemblances of the dif- 
ferent breeds. , 
The second table gives the averages of the actual milk yields 
of each animal, on those mornings when samples were taken for 
microscopic examinations for each month of lactation and these 
amounts are just half of the daily milk yield. 
The table gives also the average of each breed and a general 
average of all the breeds as also a ratio of change in yield during the 
first twelve months of lactation. This ratio shows the general 
falling off in milk yield of these animals. It will also be seen that 
there is a general resemblance of this ratio to that representing 
the monthly changes in the number of milk globules, the latter 
ratio being very nearly the former ratio reversed. By combining 
the two ratios we have the following: 
Pion Th TSG ee Ne gals Palo she tak cen ae ee 100 ~ 
MONG SEGONG i°. 5 a2ba beeline anny ee Gk ain en 126 
MOLTEN UTIIING co ik. ow: ser ipe sk bree whet alee gk. tc ee Sage 
SA TNISGEL LOMIEEMY, 3.5 5. uh Poe ee ace Ce eis WH 187 
