September, 1953] M. L. MATHUR AND S. V. DESAI 157
There was no significant difference between the first three periods ; but all the
first three periods differ significantly from the fourth. Thus the cows could not
maintain high balances during the fourth period.
If the total intakes of CaO in the cow Lenjurki (Table VIII) during unmanured
berseem period and jowar silage period are compared, they are very nearly equal,
i.e. 150.0 and 152.34 gm. respectively. But the assimilation during the respective
periods were 44.14 and 34.24 gm., i.e. 9.9 gm. more during the unmanured berseem
period. Similarly in the cow Larajbani the intakes during manured berseem period
and silage period, were equal, but the assimilation was 13.21 gm. more during the
manured berseem period. In the cow Haskila also with equal intakes (182.08 and
181.39 gm.) during lucerne and silage periods, the assimilation was 8.49 gm. more
during the feeding of lucerne. It appeared therefore that the assimilation of calcium
was better from the legumes fodders than from non-legume fodders.
It was found that all the four cows, maintained positive balances during the
four periods even when the milk production was at its peak. This may be parti-
cularly due to the chalk supplement in the feed. The highest intake of CaO, which
maintained positive balances of 9.2 gm. was 249.11 gm. during the unmanured berseem
period. But a low intake of 120.5 gm. per day during the jowar silage period also
maintained a positive balance. By increasing the intake to twice its quantity, the
positive balance improved by five grams only. Hart, et al. [1927], were able to main-
tain calcium equilibrium in case of cows giving 40 to 60 pounds milk per day with
an intake of 200 grams CaO present in a ration consisting of grain mixture, chalk
and green grasses. In the present experiments in case of a cow giving 38 lb. milk
per day positive balance of 10.67 gm. CaO per day was maintained with an average
daily intake of 182 gm. CaO present in a ration of grain mixture chalk and green
lucerne. In case of another cow giving 30 lb. milk per day, an intake of 120 gm.
of CaO present in a ration consisting of grain mixture, chalk, lucerne hay and
jowar silage maintained a balance of four grams. Forbes, et al. [1916, 1917, 1918,
1922], however, obtained negative balances in high milking cows even when a good
ration was supplemented with calcium salts or bonemeal. In the present experi-
ments calcium was retained by cows giving upto 40 lb. milk per day on a diet
consisting of grain mixture, one per cent chalk and one of the four fodders. Ber-
seem contained a high percentage of calcium and the mineral supplement of chalk
further improved the retention of calcium; chalk supplement proved to be very
useful during the feeding of jowar silage, which was poor in calcium contents. It
was observed that after a certain limit, large excess of calcium in the feed was eli-
minated in the faeces and very little in the urine.
Thus it is not the amount of calcium ingested in the food that counted, but the
amount assimilated or absorbed by the system. The assimilation was 15 to 30 per
cent of the total intake, during the various periods in the present experiments.
Miller, et al. [1924, 1925], found that the utilisation of calcium was the highest at
the height of lactation and was about 23 per cent. The indications from the present
experiments appeared to warrant the conclusion, that even in case of high milk yield-
ing cows, it was possible to maintain positive balances by ingesting high amounts of
calcium in the ration by way of calcium salts and the calcium present in green forage
containing vitamins. Green fodders as berseem and lucerne afforded better assimila-
tion than hay or silage. Though equilibrium was maintained during the feeding of