232 PRODUCTIVE FEEDING OF FARM ANIMALS 
out the lactation period than cows that are thin and poor at the 
beginning of the lactation. 
Frequency of Milking.—Under otherwise similar conditions, 
the shorter the interval between milkings, the less milk is obtained 
and the higher are the percentages of solids and butter fat con- 
tained therein. Where the interval between milkings is nearly 
equal, the differences in quality will, as a rule, be small. If the 
cows are milked three times a day, the noon milking is richest and 
the morning milking generally lowest in butter fat, while the amount 
of milk is least at noon and heaviest in ihe morning. 
Les 
45 
POUNDS MILK "}S° 
40 PB 
NI Wi 
me pa 
35 — 
PERCENT FAT 3 
25 IN 
(di 
| 
\ 
N 
ji 
aS 
15 114.0 LBS 
i} 2 3 4 5 6 7 8 9 10 We 42 
Fie. 44.—Normal changes in the monthly yield and the fat content of the milk from 
dairy cows with the progress of the lactation period, based on the results obtained in the 
Wisconsin Dairy Cow Competition, 1909-11. 
Excitement.—A feverish condition is generally accompanied by 
a decrease in milk flow and an increase in the fat content; in cases 
of severe illness, the percentage of butter fat in the milk will, how- 
ever, be abnormally low. Cows in heat, cows handled roughly, 
chased by dogs, or excited through other causes, will, as a rule, give _ 
a greatly diminished amount of milk, which will test very high. 
Temperature and Weather. ein excessively high tempera- 
tures and cold, heavy rain storms are likely to cause a “marked de- 
crease in the percentage of butter fat in the milk. Periods of 
drought, according to Van Slyke, cause a decrease in the flow of 
milk and in the contents of casein and albumen, especially the 
latter, while either no change or an increase in the percentage of 
butter fat will occur.’ 
