DAIRYING IN POETO RICO. 
17 
General results of comparative tests made to determine the dairy yield of cows 
in Porto Rico — Continued. 
Approximate milk 
Butter- 
Butterfat test per cow. 
Average 
Testing period 
(8 months). 
Number 
of cows 
tested. 
yield of herd. 
fat yield 
of herd 
per 
daily 
miLk pro- 
duction 
Daily. 
Monthly. 
month. 
Lowest. 
Highest. 
Average. 
per head. 
Pounds. 
Pounds. 
Pounds. 
Per cent. 
Per cent. 
Per cent. 
Pounds. 
Herd No. 7, Maya- 
guez. 
October, 1920 
4 
40.9 
1,267.9 
63.67 
4.5 
6.6 
5.0 
10.2 
November, 1920.. 
6 
74.4 
2,232.0 
102. 45 
4.0 
6.2 
4.59 
12.4 
December, 1920. . 
4 
54.1 
1,977.1 
72.82 
4.0 
4.6 
4.34 
13.52 
January, 1921 
5 
59.8 
1,853.8 
66.01 
4.5 
5.4 
4.81 
11.96 
February, 1921 . . . 
5 
71.4 
1,999.2 
91.87 
4.0 
5.2 
4.6 
14.28 
March, 1921 
5 
74.9 
2,321.9 
109. 92 
4.2 
5.2 
4.74 
14.98 
April, 1921 
May, 1921 
6 
95.3 
2,859.0 
135. 64 
3.8 
6.0 
4.75 
15.88 
6 
96.0 
2,976.0 
126. 70 
3.6 
5.8 
4.6 
16.0 
The results given in the foregoing table were obtained by weigh- 
ing the milk, drawing samples, and making Babcock tests of the milk. 
As the seasons vary but little in Porto Rico and the cattle are allowed 
' to graze the year round, the results are more uniform for the months 
during which the study was made than they would be in temperate 
regions. Only those cows which were being milked at the respective 
dairies were tested. Some of them were coming in fresh and others 
were going dry through the period of the test. The results from in- 
dividual cases are rather indefinite, but the average for the whole 
herd is very good. Herd Xo. 1 was pastured on Guinea grass at 
Guanica, a dry section of the island on the south coast. The animals 
were milked once a day, with the calf. Herds Xos. 2, 3, and 4 had 
Guinea grass as the principal feed and were kept at Lajas, a dry sec- 
tion in the southwestern part of the island. This section, which 
has a limestone soil, is considered ideal for cattle raising. The 
cows in these herds were milked once a dav, with the calf. Herd Xo. 
5 carries more or less improved blood, having been bred to the sta- 
tion bulls. This herd was kept near Mayaguez, not far from the ex- 
periment station, in the western part of the island. The cows were 
milked twice a day, some with and some without the calf. Herd 
Xo. 6 belongs to the College of Agriculture of the University of 
Porto Rico, Mayaguez, and consists of purebred animals. The cows 
in this herd were milked twice a day without the calf. Herd Xo. 
7 is made of high-grade animals, mostly of Guernsey blood, and 
belongs to the station. (PL II, Fig. 2.) The cows were milked 
twice a dav, without the calf. 
The general results indicate the need of introduced blood to im- 
prove the milk stock of the island, and more modern methods of 
milking and handling than are now used. It is a noticeable fact that 
the native cows varied greatly in yields of milk and butterfat. The 
high-testing cows gave such large yields as to indicate that they are 
