16 
BULLETIN 29, PORTO RICO EXPERIMENT STATION. 
following a method devised by the Dairy Division, Bureau of Ani- 
mal Industry, United States Department of Agriculture, 1 and the 
data are recorded at the station for those dairymen in Porto Rico 
who are anxious to learn (1) to determine the actual value of each 
cow in their herds; (2) to compare the dairy yield of native with 
that of improved cattle; (3) the present condition of the industry; 
and (4) methods of improving it. The following table gives the 
general results obtained, but does not show the cost or profits : 
General results of comparative tests made to determine the dairy yield of coics 
in Porto Rico. 
Testing period 
(8 months). 
Number 
of cows 
tested. 
Approximate milk 
yield of herd. 
Butter- 
fat yield 
of herd 
per 
Butterfat test per cow. 
Average 
daily 
milk pro- 
duction 
Daily. 
Monthly. 
month. 
Lowest. 
Highest. 
Average. 
per head. 
Herd (native) No. 1, 
Guanica: 
Pounds. 
Pounds. 
Pounds. 
Per cent. 
Per cent. 
Per cent. 
Pounds. 
November, 1920.. 
66 
327.2 
9, 816. 
382. 32 
1.7 
6.8 
3.46 
4.95 
December, 1920.. 
82 
459.7 
14, 203. 3 
548. 42 
1.8 
6.4 
3.86 
5.60 
Januarv, 1921 
77 
444.3 
13, 778. 5 
520.80 
1.8 
6.6 
3.77 
5.75 
February, 1921 . . . 
7; 
505.7 
14, 160. 6 
472. 98 
1.3 
6.0 
3.34 
7.12 
March, 1921 
62 
406.7 
12, 558. 1 
409. 15 
1.5 
7.3 
3.26 
6.56 
April, 1921 
50 
291.4 
8, 742. 
329.56 
1.8 
8.2 
3.77 
5.83 
May, 1921 
54 
254.8 
7, 898. 8 
282. 14 
1.6 
6.7 
3.57 
4.72 
June, 1921 
73 
524.5 
15, 735. 
446.76 
1.0 
6.5 
2.85 
7.18 
Herd No. 2, Lajas: 
November, 1920.. 
104 
515.9 
15, 478. 5 
724. 71 
1.0 
8.8 
4.68 
4.96 
December, 1920... 
105 
594.5 
18, 429. 5 
858.80 
2.0 
11.0 
4.66 
5.66 
Januarv, 1921 
103 
524.8 
16, 391. 4 
786.05 
2.0 
9.0 
4.79 
5.09 
Februarv, 1921... 
109 
648.4 
18, 155. 
738. 91 
1.4 
8.5 
4.07 
5.95 
March, 1921 
100 
653.6 
20, 431. 1 
910. 87 
1.6 
7.4 
4.45 
6.54 
April, 1921 
95 
505.4 
15, 162. 
719. 88 
2.4 
9.4 
4.75 
5.32 
May, 1921 
104 
443.8 
13, 757. 8 
780. 70 
3.0 
11.0 
5.67 
4.27 
June, 1921 
114 
787.7 
23, 631. 
893. 97 
1.5 
7.7 
3.78 
6.90 
Herd No. 3, Lajas: 
November, 1920. . 
50 
373.0 
11, 190. 
489. 60 
2.0 
7.6 
4.38 
7.46 
December, 1920. . . 
54 
341.6 
10, 589. 6 
516. 90 
2.6 
7.6 
4.88 
6.32 
January, 1921 
46 
326.3 
10, 086. 3 
441.36 
2.8 
7.2 
4.37 
7.09 
February, 1921 . . . 
43 
254.8 
7, 142. 8 
310. 62 
2.2 
7.5 
4.35 
5.92 
March, 1921 
41 
289.6 
8,977.8 
370. 01 
2.2 
7.6 
4.12 
7.06 
April. 1921 
55 
"462. 9 
13, 887. 
555. 87 
1.8 
8.5 
4.03 
8.41 
May,l921 
56 
65 
401.0 
639.8 
12,231.0 
19, 194. 
461. 11 
637.88 
2.4 
1.7 
6.6 
6.2 
3.74 
3.84 
7.16 
June, 1921 
9.84 
Herd No. 4. Lajas: 
November, 1920. . 
104 
836.3 
25, 089. 
1, 145. 58 
2.2 
8.4 
4.57 
8.04 
December, 1920. . . 
109 
978.2 
30,324.9 
1, 303. 83 
2.0 
6.6 
4.30 
8.97 
January, 1921 
106 
555.0 
17, 206. 6 
837. 49 
2.4 
9.2 
4.86 
5.24 
February, 1921 . . . 
114 
471.0 
13,294.6 
588. 30 
1.1 
8.2 
4.16 
4.13 
March, 1921 
111 
612.3 
18, 980. 6 
917. 54 
3.0 
8.8 
4.83 
5.51 
April, 1921 
122 
775.0 
19, 854. 
935. 18 
2.4 
7.0 
4.71 
6.35 
May,1921 
112 
126 
504.3 
770.1 
15, 633. 
23, 103. 
689. 60 
926.44 
1.8 
1.8 
6.7 
10.0 
4.41 
4.01 
4.50 
June, 1921 
6.11 
Herd No. 5, Maya- 
guez: 
October, 1920 
17 
178.6 
5, 536. 6 
281. 26 
4.0 
6.7 
5.08 
10.50 
November, 1920. . 
23 
208.3 
6, 249. 
285.03 
3.0 
8.0 
4.56 
9.06 
December, 1920. . . 
19 
173.2 
5,369.2 
276. 52 
4.2 
8.5 
5.15 
9.11 
January, 1921 
18 
189.6 
5, 877. 
285.96 
3.8 
7.7 
4.87 
10.53 
February, 1921 . . . 
18 
177.2 
4, 961. 6 
234. 76 
3.9 
7.2 
4.62 
9.84 
March, 1921 
17 
220.5 
6, 823. 1 
306.59 
3.5 
5.8 
4.49 
12.97 
April, 1921 
20 
226. 5 
6, 795. 
312. 76 
3.0 
6.5 
4.60 
11.32 
May, 1921 
21 
255.1 
7,908.1 
353. 17 
3.3 
6.4 
4.47 
12.15 
Herd No. 6, Maya- 
guez: 
October, 1920 
7 
69.4 
2,151.4 
112.84 
4.8 
6.0 
5.24 
9.91 
November, 1920.. 
7 
66.0 
1,980.0 
108.45 
4.9 
5.9 
4.90 
9.43 
December, 1920. . 
7 
59.4 
1,841.4 
103.11 
5.0 
6.3 
5.60 
8.48 
January, 1921 
7 
55.8 
1,729.8 
93.95 
4.8 
7.4 
5.43 
7.97 
February, 1921... 
6 
46.9 
1,312.8 
69. .58* 
4.5 
6.2 
5.3 
7.81 
March, 1921 
4 
44.1 
1,367.1 
71.52 
4.4 
6.0 
5.5 
11.02 
April, 1921 
May, 1921 
6 
74.0 
2,220.0 
97.49 
3.7 
5.7 
4.39 
12.33 
6 
67.2 
2,083.2 
92.67 
3.6 
6.2 
4.45 
11.20 
1 Bureau of Animal Industry Circ. 179, Cow Testing Associations. 
