Vitamins. Both the fat-soluble and the
water-soluble vitamins are present in milk.
Whole milk, cream, butter, and cheese made
from cream or whole milk are excellent
sources of vitamin A. The amount present
varies with the amount of green food avail¬
able to the cow. Since vitamin A is stable to
heat, boiled, dried, canned, and pasteurized
whole milks and cream still retain a large part
of their original content of this vitamin.
Butter is an excellent source of vitamin A.
Milk is only a fair source of the B vitamins
as a group. It is an excellent source of ribo¬
flavin and contains small amounts of thia¬
mine, niacin, and the other B factors. These
vitamins are all water-soluble and so are most
abundant in the nonfat portion of the milk.
Dried skim milk is one of the cheapest food
sources of riboflavin. Small and variable
amounts of vitamin C are present in raw
milk. This vitamin is very unstable, so that
heated milk contains little or none.
Milk fat may contain a small quantity of
vitamin D. The amount varies with the
season and the extent to which the cows are
exposed to the sunlight, while irradiated milk
is available which contains vitamin D.
Variations in Composition. A number of
factors influence the composition of milk.
Use is made of these factors in the manage¬
ment of herds to obtain milk of the general
composition desired. The amount of fat is
characteristic of the breed. Jersey cows give
milk with the highest percentage of fat (an
average of 5 per cent), while the average for
Holstein milk is 3.5 per cent. Between these
extremes range the Guernsey, the Ayrshire,
and the Dutch Belt, in descending order.
Individual animals and families within breeds
have certain tendencies in milk production
which are transmitted by inheritance. These
differences are shown in the amount of milk
and the amount of fat it contains. Breeding
for milk production within the different
breeds and by crossbreeding is based on these
individual and family differences.
Feeding influences both the quality and
the quantity of milk. A well-fed cow gives
more milk and a better quality of milk than
one that is poorly fed. However, food has
more influence upon the quantity than upon
the composition of milk. In general, both
quantity and composition of milk are more
affected by breed than by amounts and
kind of feed, but no cow will give the best
results in milk production unless properly
fed.
Seasonal and daily variations in composi¬
tion also occur. The milk of well-fed cows is
usually richer in winter than in summer ow-
[115]
r
ing to the prevalence of more succulent food
during the summer months. The morning
milk is of greater quantity, and contains less
fat than the evening milk.
Frequency of milking affects the quantity
of milk obtained but has little effect on com¬
position. If milked three times a day the
cow will yield from 10 to 15 per cent more
milk than if milked only twice, as is custom¬
ary. This gain usually is not considered
sufficient to offset the increased labor cost of
the extra milking.
While these variations can be followed in
the individual cow, in the milk from a mixed
herd the differences tend to neutralize one
another and there is less variation from day
to day than in the milk from one cow. The
differences in the compositions of milk from
different herds are controlled largely by
breed, care, and feeding.
Page 107
Presented as published in 1935. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
Vitamins. Both the fat-soluble and the water-soluble vitamins are present in milk. Whole milk, cream, butter, and cheese made from cream or whole milk are excellent sources of vitamin A. The amount present varies with the amount of green food avail¬ able to the cow. Since vitamin A is stable to heat, boiled, dried, canned, and pasteurized whole milks and cream still retain a large part of their original content of this vitamin. Butter is an excellent source of vitamin A.
Milk is only a fair source of the B vitamins as a group. It is an excellent source of ribo¬ flavin and contains small amounts of thia¬ mine, niacin, and the other B factors. These
vitamins are all water-soluble and so are most abundant in the nonfat portion of the milk. Dried skim milk is one of the cheapest food sources of riboflavin. Small and variable amounts of vitamin C are present in raw milk. This vitamin is very unstable, so that heated milk contains little or none.
Milk fat may contain a small quantity of vitamin D. The amount varies with the season and the extent to which the cows are exposed to the sunlight, while irradiated milk is available which contains vitamin D.
Variations in Composition. A number of factors influence the composition of milk. Use is made of these factors in the manage¬ ment of herds to obtain milk of the general composition desired. The amount of fat is characteristic of the breed. Jersey cows give milk with the highest percentage of fat (an average of 5 per cent), while the average for Holstein milk is 3.5 per cent. Between these extremes range the Guernsey, the Ayrshire, and the Dutch Belt, in descending order. Individual animals and families within breeds have certain tendencies in milk production which are transmitted by inheritance. These differences are shown in the amount of milk and the amount of fat it contains. Breeding for milk production within the different breeds and by crossbreeding is based on these individual and family differences.
Feeding influences both the quality and the quantity of milk. A well-fed cow gives more milk and a better quality of milk than one that is poorly fed. However, food has more influence upon the quantity than upon the composition of milk. In general, both quantity and composition of milk are more affected by breed than by amounts and kind of feed, but no cow will give the best results in milk production unless properly fed.
Seasonal and daily variations in composi¬ tion also occur. The milk of well-fed cows is usually richer in winter than in summer ow-
[115]
r
ing to the prevalence of more succulent food during the summer months. The morning milk is of greater quantity, and contains less fat than the evening milk.
Frequency of milking affects the quantity of milk obtained but has little effect on com¬ position. If milked three times a day the cow will yield from 10 to 15 per cent more milk than if milked only twice, as is custom¬ ary. This gain usually is not considered sufficient to offset the increased labor cost of the extra milking.
While these variations can be followed in the individual cow, in the milk from a mixed herd the differences tend to neutralize one another and there is less variation from day to day than in the milk from one cow. The differences in the compositions of milk from different herds are controlled largely by breed, care, and feeding.