———_ 
| 886 
will, in every instance, be found to arise either 
wholly or almost wholly from increase or dimi- 
nution of absolute nourishment. A cow kept 
through winter upon mere straw will cease to 
give milk, and when fed in spring upon green for- 
age will give a fair quantity of milk; but she 
owes the cessation and the restoral of the se- 
cretion to respectively the diminution and the 
increase of her nourishment, and not at all to 
the change of form or of outward substance in 
which the nourishment is administered. Let 
cows receive through winter nearly as large a 
proportion of nutritive matter as is contained in 
the clover, lucern, and fresh grasses which they 
eat in summer; and—no matter in what precise 
substance or mixture that matter may be con- 
tained—they will yield a winter’s produce of milk 
quite as rich in caseous and butyraceous ingre- 
dients as the summer’s produce, and far more 
ample in quantity than almost any dairyman 
with old-fashioned notions would imagine to be 
possible. The great practical error on this sub- 
ject consists, not in giving wrong kinds of food, 
but in not so proportioning and preparing it as 
| to render an average ration of it equally rich in 
_ the elements of nutrition, and especially in nitro- 
| genous elements, as an average ration of the 
_ green and succulent food of summer. 
Assuming 33 lbs. of meadow hay per day to be 
| the proper ration for a milk-cow, and referring 
to the article Foop for a view of the elements of 
| nutrition in the various substances usually given 
to cattle, and of the bulk or weight of each of 
these which is equal in nutrimental value to 33 
Ibs. of meadow hay, we may rapidly follow M. 
_ Boussingault through a course of well-conducted 
experiments by which he ascertained the con- 
trolling power of different kinds of food over the 
quantity and the chemical constitution of milk. 
One cow, who was 200 days after calving and 
was again pregnant, and who therefore was in 
a physiological condition to fall gradually and 
even rapidly away in her produce of milk, was 
subjected to seven distinct courses of feeding, in 
periods of from 7 to 14 days, and was found, 
during all the courses, and notwithstanding very 
wide diversity in the substances of their food, to 
yield milk of almost exactly uniform chemical 
constitution. She first, during seven days, re- 
ceived daily, 33 lbs. of hay, and she then yielded 
milk consisting of 3:0 per cent. of caseum, 4'5 of 
butter, 4°7 of sugar of milk, 0:1 of ash of caseum, 
and 87°7 of water; she next received daily, dur- 
ing eight days, turnips equal to 29°7 lbs. of hay, 
and straw equal to 3'3 lbs. of hay, and she then 
yielded milk consisting of 3:0 per cent. of caseum, 
4-2 of butter, 5:0 of sugar of milk, 0:2 of ash of 
caseum, and 87°6 of water; she next received 
daily, during fourteen days, field beet equal to 
29°7 lbs. of hay, and chopped straw equal to 3°6 
Ibs. of hay, and she then yielded milk consisting 
of 3:4 per cent. of caseum, 4:0 of butter, 5°3 of 
| sugar of milk, 0°2 of ash of caseum, and 87:1 of 
COW. 
water; she next received daily, during eleven 
days, raw potatoes equal to 29:7 lbs. of hay, and 
chopped straw equal to 3°6 lbs. of hay, and she 
then yielded milk containing 3:4 per cent. of 
caseum, 4:0 of butter, 5:9 of sugar of milk, 0:2 of 
ash of caseum, and 86°5 of water ; she was next, 
in consequence of the heating effect of the last 
regimen, and for a reason affecting the quantity 
of her produce, returned for thirty days to her 
original diet of 33 lbs. of hay per day,—she was 
afterwards fed for ten days on the same ration of 
potatoes and straw as before the return to the 
hay, but with the addition to each day’s allow- 
ance of about 24 ounces of salt,—and she was 
next fed for a time on a quantity of Jerusalem 
artichokes equal to 33 lbs. of hay per day, and 
she then yielded milk consisting of 3'3 per cent. 
of caseum, 3'5 of butter, 5°5 of sugar of milk, 0:2 
of ash of caseum, and 87°5 of water. The aver- 
age daily quantity of milk during the first course 
of hay was 934 pints; during the course of 
turnips and cut straw, 10°5 pints; during the 
course of field beet and chopped straw, 9'8 pints ; 
during the first course of raw potatoes and chop- 
ped straw, 8°7 pints; during the second course of 
hay, 62 pints; during the second course of 
raw potatoes and chopped straw, 5:9, or very 
nearly 6 pints; and during the course of Jeru- 
salem artichokes, slightly above 6 pints. The 
grand result, therefore, is that the chemical con- 
stitution, or what is popularly called the richness 
of the milk, was not appreciably affected by al- 
ternations and very great changes of diet,—that 
the quantity of the milk was affected principally 
by the physiological condition of the cow, and 
perhaps slightly by some circumstances which | 
are not noticed in the record of the experiments, 
—and that the main point, in altering the diet 
of a cow, is to take care that she receive a full 
allowance of nutritious food, and in consequence | 
have wherewith to secrete, not only all the or- 
dinary juices, but as much milk as the state of her | 
| system will admit. 
But two points of considerable importance re- 
mained to be ascertained, — whether the milk 
soon after calving differs in chemical constitution 
from milk at a remote period after calving, and 
whether fresh-cut clover exerts any such power 
upon the butyraceous richness of either recent or 
remote milk as is confidently ascribed to it by 
the great majority of dairymen. A cow, 24 days 
after. calving, and while fed upon a mixture of 
hay and green clover, yielded at the rate of 18:6 
pints of milk per day, consisting of 3:0 per cent. 
of caseum, 3'5 of butter, 4°5 of sugar of milk, 02 
of ash of caseum, and 88°8 of water; and the 
same cow, 35 days after calving, and while fed 
upon green clover, produced 21:2 pints of milk 
per day, consisting of 3'1 per cent. of caseum, 5°6 
of butter, 4°2 of sugar of milk, 0°3 of ash of cas- 
eum, and 86°8 of water. A sudden and extra- 
ordinary increase in the proportion of butter ap= 
peared in the second of these analyses; and to 
