236 Influence of Dietary Fat on yield and Composition of Butterfat
oils of iodine values 45 and 17 respectively and peanut oil of iodine value 17. The untreated ground-
nut oil of iodine value 85 increased the iodine value of the butterfat by 4.6 and lowered the R. M. and
Polenske values by 6.6 and 0.6 respectively. Hydrogenated groundnut oil of iodine value 45 had
more or less the same effect. But in the case of hydrogenated groundnut oil of iodine value 17, the
change in composition was less marked, butterfat being almost of similar composition as the control
butter. Palm-kernel oil of iodine value 17 lowered the iodine and R. M. values by 5 and 1.2 units
respectively and increased the Polenske value slightly. In neither of the cases was there any signi-
ficant increase in the milk yield or fat output. Moghul et al [1945] have reported that 1½ lb. of cotton-
seed oil had a beneficial effect on the milk yield of Scindhi cows and sesame and coconut oils had
more pronounced effect on the milk yield and fat output of Murrah buffaloes at the same time affect-
ing the composition of the resulting butterfat considerably in all cases. But no work seems to have
been done to study the effect of feeding hydrogenated oils on the milk yield and fat output of the
indigenous breed of cattle. Therefore, a series of experiments was conducted to study the effect of
feeding oils of two diffent degrees of saturation on the milk yield and butterfat output of Scindhi
cows and Murrah buffaloes and the results obtained are presented in this paper.
EXPERIMENTAL
Nine Scindhi cows and nine Murrah buffaloes of almost the same age, body weight, stage of
lactation and milk yield were selected for the experiment from the herd of the Imperial Dairy Research
Institute. These were divided into three equal groups, one for control and the other two for experi-
mental purposes. The control group received only the normal ration fed to the Institute herd through-
out the period. The normal concentrate ration of the Institute herd consisted of a mixture of wheat
bran, gram, gram husk and groundnut cake in the proportion of 4.0 : 1.5 : 2.0 : 2.5. This mixture
was fed at the rate of one pound for every two pounds of milk yielded by the animal. The roughage
consisted of 50 lb. of green grass (mixture of Guinea and Napier grasses) and 3 lb. of ragi straw in the
case of cows and 70 lb. green grass and 3 lb. of ragi straw for buffaloes. Till the actual feeding of the
vanaspati was started, all the animals, both control and experimental, were receiving only this ration.
The milk yield and fat percentage were noted for all the animals for a week, at the end of which a
day's yield of milk was separately collected from each animal for butter making. After this initial
control period for all the animals, including the experimental ones, one group of cows and buffaloes
was fed ½ lb. of hydrogenated coconut oil and the other group of cows and buffaloes ½ lb. groundnut
oil vanaspati per head on the first day. This was increased to 1 lb. on the second day and thereafter
1½ lb. were fed per head per day for a fortnight besides the normal ration which the animals were
already receiving. The control animals received only the normal ration all the time. The milk
yield and the percentage of fat in milk were recorded systematically every day. Every 5th day a
day's milk was separately collected from each animal for butter making and this butter was then
melted into ghee at 115ºC. filtered and analysed for R. M., Polenske and Iodine Values and B. R.
reading. The oil feeding was stopped after 15 days but the milk yield and fat percentage of milk
were observed for another one week at the end of which again a day's milk was collected for butter
making. The chemical composition of the vanaspathis fed to the animals is given in Table I.
TABLE I
Composition of vanaspathis fed to the animals
Nature of the fat
Groundnut vanaspathi . . . . . .
Cooonut vanaspathi . . . . . .
R. M.
value
0.0
5.3
Polenske
value
0.2
7.2
Iodine
value
70.4
4.2
B. R.
reading
52.9
38.6