146 EFFECT OF DIFFERENT FODDERS IN SAHIWAL COWS
[Vol. XXIII, Part III,
250 c.c. and kept in sealed stoppered bottles in cold room. Five hundred c.c. of
urine were evaporated to dryness and ashed. The ash was dissolved in. dilute HCl
filtered and made up to a known volume (250 c.c.) and kept in sealed stoppered
bottles in cold room. Chlorine in milk and urine samples was determined daily
and other elements after the collection period was over.
Five to ten grams of the oven dried material was weighed in a platinum dish
and ashed on a low flamed rose top or in muffle furnace at 500°C. The ash was
moistened with water with the help of a pipette and transferred to a beaker with
a fine jet of water. Any particles of ash still sticking to the dish were rubbed with
a rubber policeman and taken in the beaker. Forty c.c. of dilute HCl (1+1) was
then added and the beaker kept on the water bath to digest and then evaporated
to dryness. It was kept on water bath for ½ hour to dehydrate silica. The dehydra-
tion was completed by placing it in an air oven at 105°C. It was cooled and again
treated with 10 c.c. HCl (1+1) and the process repeated. The beaker was then
removed. 50 c.c. diluted HCl added and heated on water bath. The contents
were then filtered and collected in 250 c.c.volumetric flask and made up to 250 c.c.
Determination of calcium
Fifty to hundred c.c. of aliquot was taken in a 150 c.c. beaker, a few grams
ammonium chloride and 10 to 15 c.c. of 10 per cent solution of sodium citrate were
added to prevent precipitation of iron and aluminium and stirred; two drops of
methyl red were added followed by 10 c.c. of saturated solution of ammonium oxalate.
The contents of the beaker were heated to boiling and dilute ammonia was added
drop by drop with a pipette, until the indicator showed orange colour and calcium
oxalate precipitated. The beaker was covered and kept overnight. It was. filtered,
washed and the filtrate kept for magnesium. The rest of the procedure was as
described by Desai and Mathur [1945].
Determination of magnesium
The filtrate and washings after removing the calcium were evaporated to
about 100 c.c. in a 250 c.c. beaker, 10 c.c. of 10 per cent ammonium phosphate
solution was then added and the contents heated to boiling. The beaker was re-
moved the flame and NH 4 OH (1: 4) was added with constant stirring with a glass
rod, until the precipitation was apparently complete. At this stage there was
danger of hydroxides being precipitated if ammonia was strong; in that case the
precipitate was dissolved in HCl and the process repeated. With little care and
practice only magnesium ammonium phosphate was reprecipitated. It was then
allowed to cool and then 10 c.c. or ten per cent of the volume in beaker, of strong
ammonia was added, the contents vigorously stirred and allowed to stand in cool
place overnight. The precipitate was filtered and washed free from chlorides
with cold dilute NH 4 OH (1 :10). It was then allowed to remain over night or
washed with two or three washings of water and alcohol to remove free ammonia.
The filter paper was taken in the same beaker, 20 to 25 c.c. water added and a known
volume of decinormal HCl to dissolve the precipitate. The excess was back titrated
with decinormal caustic soda using methyl orange as indicator.