THE INFLUENCE OF DIETARY FAT ON THE YIELD AND COMPOSITION
OF BUTTERFAT.
By I. P. SINGHVERMA, T. M. PAUL, C. P. ANANTAKRI SHNAN and M. C. RANGASWAMY, IMperial Dairy
Research Institute, Bangalore
(Received for publication on 5 November 1946)
B UTTERFAT, being the most valuable constituent of milk, determines the quality of
milk and numerous investigations have been made to study the various factors affecting its
yield . Although there is a certain amount of disagreement among the findings of the various workers,
the concensus of opinion is that fat percentage in milk is an inherited quality of the particular indi-
vidual animal and the breed to which it belongs. In countries where large amounts of milk are
utilized for the manufacture of butter, this has led to the selective breeding of certain strains of animals
with higher fat percentage. Of the English breeds of cows, Jersey and Guernsey give higher fat
percentage in milk than Freisian or Shorthorn. In India Scindhi and Gir cows give milk richer in
butterfat as compared to many of the English breeds and the Indian buffalo is unrivaled in this
respect among the dairy animals of the world, so much so that it has been called a veritable butter
producing machine. This being the case there is no wonder if buffaloes are prefered in India where
ghee is the most important dairy product. But even among animals of the same breed variation in
the fat content of milk has been observed from time to time. This has led to many investigations
into the causes of the fluctuation in the fat percentage of the milk and it has been found that factors
like individuality, the interval between two successive milkings, time of milking, stage of lactation,
season of the year, and the age of the animal are mainly responsible for the fluctuations in the fat
percentage of the milk of the same animal at different periods or between the milks of different animals
of the same breed. The influence of the feed consumed by the animal on the yield of milkfat was
recognized only later, but now it is definitely known that the food consumed by the animal plays an
important part in the yield of both milk and milkfat.
The ordinary farmer knows the importance of the concentrate cattle feeds like oil cakes as food
for dairy cattle. The albuminoids of the cakes primarily contribute to the increased production of
milk. It is quite natural that the cakes might contain considerable amounts of oils but the function
of these oils in the cattle feeds has not been fully realized. Numerous investigations have been made
both in Europe and in America to study the effect of various oils on the yields of milk and butterfat.
In the case of a supplementary ration of fat in addition to an already adequate ration, a peculiar
situation is created whereby an additional amount of fat is made available to the mammary glands
of the animal for conversion into milkfat. If this hypothesis is correct, one can naturally expect an
increase in the fat content of milk when oils are fed to dairy animals. Depending upon the nature
of the fat fed, the effect may be qualitative or quantitative or even both. It is more than clear that
the analytical constants of ghee (butterfat) may be affected within a very short time by a supple-
mentary feed of any fat to the animal. This is particularly important in view of the fact that butter
and ghee are judged for purity by the analytical constants.
India produces large amounts of a variety of edible oils and hydrogenation of these oils is also
becoming very popular. In the near future, large amounts of hydrogenated oils may become avail-
able at a cheap rate. If the untreated oil has some effect on the yield and composition of the butter-
fat as reported by Moghul et al [1945], it is to be naturally expected that hydrogenated oils also should
exert some influence on the yield and composition of butterfat. Owing to the change in the degree
of unsaturation when an oil is hydrogenated, it is expected that the effect of vanaspati feeding would
be different from that of the untreated oil. Again if the hydrogenated oils can be economically
converted into the more nutritious butterfat through the medium of the dairy animal it will really
be an achievement. But so far no systematic work has been done to study this aspect of the problem.
Dustman et al [1941] observed that when one pound of hydrogenated soyabean oil was fed to cows,
the iodine number increased slightly, showing a slight desaturation by the cow. Hilditch and Jasper-
son [1943], supplemented the basal ration of dairy cows with groundnut oil, hydrogenated groundnut
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