264     Carotene and Vitamin-A Contents of butter-fat in cows

respectively, which clearly show the effect of dietary carotene on the charac-
teristics of butter.

The experimental results with red palm oil (Table IX) are very interest-
ing. Thus in the depletion period, when the cow was only on straw and
concentrate, the butter-fats gave the following values :—R. W. value—26.8 ;
Iodine value—33.6 ; Carotene content—3.8 Y. U. per grm. and vitamin-A
content—7.6 B. U. per grm. when the cow was given 4 oz. of red palm oil
daily (Malayan variety containing 56.8 mg. of carotene per 100 grm. of the
oil), the Reichert value increased from 26.8 to 28.2 ; the Iodine number also
increased from 33.6 to 36. 6, the carotene from 3.8 Y. U. to 6.8 Y. U. and
the vitamin.A increased from 7.6 B. U. to 10.4 B. U. At the end of the
2nd week as the cow was given 8 oz. of red palm oil daily, the Reichert value
exhibited a further increase, viz., from 28.2 to 29.4 and the Iodine value
from 36.6 to 37.4, carotene from 6.8 to 10.4 and the vitmain-A content
from 10.4 to 14.8. On return to the normal basal diet at the end of the 3rd
week, all the values gradually returned to the normal, most markedly the
carotene and vitamin-A contents. The Iodine value rather slightly increased
whilst the Reichert value diminished from 29.4 c.c. in the 4th week to 28.4 c.c.
in the 5th week.

The progressive increase in the carotene content of butter by ingesting
increasing dosages of red palm oil is, however, somewhat striking in view
that other workers [ Dann, 1932 ; Crawford, Perry and Zilva, 1932 ; Fraps
and Treichler, 1932 ] had shown that provided the cows' diet is not really
deficient in the vitamin-A, further additions to the diet had relatively little
effect on milk.

Further works are in contemplation on this line which are no doubt of
considerable importance from nutritional view-point.

All the above results considered together are highly suggestive and
demonstrate that the Lipochrome pigment carotene might play some part
in the production of lower fatty glycerides in butter-fats. This is probable
for carotene being a readily oxidisable substance may induce the oxidation
of fatty acids with which the pigment is closely associated. In Vikrampur,
wherefrom all the butter-fats have been procured, there is no fixed time for
calving. The cows are generally calved in such a way that the milk output
of a dairy does not vary much from the normal output. The effects of the
period of lactation on the Reichert-values of butter-fats will, therefore, be
minimum. Oil cakes are also used only in small quantities in that locality
(maximum 1 lb. per day) so that the effects of the administration of the oil
cakes can only be negligible. In fact most of the cows go without any oil
cakes. The Reichert-values given in the tables will, therefore, indicate the
effects of the climate and the carotene contents of the feeding stuff mainly.
The high Reichert values during the winter are coincident with the high
carotene content of the feeding-stuff in spite of the cold temperature of the