Joumal of Agricultural Research 
Vol. XXIX, No. 12 
610 
reductions in these rations in the second 
periods of Experiments I to V. The 
curve in Experiment I shows that a 
sharp reduction in both protein and 
energy content of the ration of a milk¬ 
ing cow produces a decided and abrupt 
drop in plasma amino N. In four days 
it dropped from 2.3 to 1.25 mg. per 
100 c. c., or 46 per cent. 
Experiment II shows that a similar 
drop in plasma amino N occurs when 
the energy content of the ration is 
reduced without materially altering the 
dietary protein. In period 1 of this 
experiment the cow was just recovering 
from the effects of a previous experi¬ 
ment, and the plasma amino N of 1.95 
mg. per 100 c. .c. was low. The energy 
content of the ration (Table I) was 
relatively higher than in Experiment I. 
Yet the plasma amino N dropped to 
1.64 mg. per 100 c. c., or 16 per cent. 
In Experiment II determinations 
were made of the glucose in the blood 
and plasma in order to determine 
whether this blood constituent under¬ 
went changes parallel to the changes 
in animo N. The results indicate that 
this was not the case; apparently the 
sugar content of the blood samples was 
more affected by the disturbance 
caused to the animal in obtaining them 
than by the changes in the diet. (See 
Table IV and its footnotes.) 
Table IV .—Experiment 77, cow 54- Change in energy content of ration 
Pe¬ 
riod 
No. 
Date 
Milk (daily) 
Blood 
Yield 
j 
| 
Nitrogen | Fat 
i 
I 
Lactose 
Amino N ° 
Sugar 
Blood 
(mg. 
per 100 
c. c.) 
Plasma 
(mg. 
per 100 
c. c.) 
Blood 
(mg. 
per 100 
c. c.) 
Plasma 
(mg. 
per 100 
c. c.) 
1. 
1920 
Nov. 25.... 
Nov. 26.... 
Nov. 27_ 
Nov. 28.... 
Nov. 29_ 
Nov. 30.... 
Dec. 1. 
Kg . 
11.66 
11.34 
11.84 
11.11 
11.34 
10.52 
11.16 
11.16 
11.09 
10.71 
10.52 
10.93 
10.39 
10.57 
10.61 
10.80 
10.30 
10.39 
9.35 
9.34 
9.66 
9.33 
9. 66 
10.61 
10.61 
10.48 
10.52 
10.93 
10.66 
10.30 
9.98 
10.43 
9.71 
9.89 
P.ct. 
Gm. 
P. ct. 
Gm. 
P. ct. 
Gm. 
1. 
0.4837 
.4946 
54.85 
58.55 
3.44 
3.64 
390.1 
430.9 
5.23 
5.34 
593.1 
632.2 
1_ 
2. 
4.05 
1.95 
64.1 
77.1 
2_ 
.4598 
52.14 
3. 77 
417.5 
5.39 
611.2 
2. 
2_ 
.4539 
.4714 
50.65 
52.68 
3. 39 
3.37 
378.3 
376.1 
5.42 
628.2 
2. 
Dec. 2. 
2. 
Dec. 3-4_ 
Dec. 5_ 
2. 
.4592 
.4661 
49.16 
49.05 
3.49 
3. 37 
373.6 
354.7 
5.37 
5. 39 
574.9 
567.2 
2. 
Dec. 6. 
2. 
Den. 7 
3.87 
1.64 
63.5 
70.9 
2. 
Dec. 8. 
.4419 
.4547 
.4502 
.4646 
.4569 
.4424 
45.91 
48.06 
48.01 
50.16 
47.04 
45.95 
3. 47 
3. 61 
3.43 
3.49 
3.20 
3.21 
360.5 
381.5 
364.1 
376.8 
329.5 
333.5 
2. 
Dec. 10_ 
2. 
Dec. 11. 
2. 
Dec. 12. 
2. 
Dec. 13. 
2. 
Dec. 15_ 
2_ 
Dec. 16_ 
3.72 
1.72 
6 73. 6 
b 89.8 
2. 
Dec. 17. 
2. 
Dec. 18-24. 
Dec. 25. 
3. 
3. 
Dec. 26- 
3. 
Dec. 27. 
3. 
Dec. 28. 
3. 
Dec. 29-31.. 
1921 
Jan. 1-7_ 
Jan. 8. 
3. 
3_ 
.4702 
51.40 
3.40 
3.39 
3.40 
3.43 
3.86 
3. 51 
3. 51 
371.7 
361.4 
350.1 
342.3 
402.7 
340. 7 
347.1 
3. 
Jan. 9. 
3. 
Jan.10. 
.4675 
48.14 
3. 
Jan. 11_ 
3_ 
Jan. 12__ 
.4772 
49.79 
3. 
Jan.13. 
3_ 
Jan. 15- 
.4819 
47.65 
4.14 
2.47 
‘54.7 
‘61.3 
« Average difference in duplicate amino-N determinations in blood 3 per cent, and in plasma 4.3 per 
cent. 
h This cow was most disturbed in obtaining this blood sample. 
‘ This cow was least disturbed in obtaining this blood sample. 
