White Bluffs spokesman. [volume] (White Bluffs, Wash.) 1907-1938, 1929-07-26
why MILK TESTS VARY

Why does the milk of any COW or
any herd, vary from day to day or
week to week. This is most per-
picking question, but is being asked
daily ty any dairyman having his
herd or individual cows tested for
tutterfat by the Babcock method.
Even yet the most expert chemists
cannot explain all the changes that
occur, and we must admit that no one
has yet discovered all the laws that
govern the process of the secretion
of milk and butterfat.
We do know that changes in test
always occur even from one milking
to another even when every possible
condition we can discover affecting
the COW, is kept the same. For in
stance, cows on test for official record
are treated with as nearly perfect reg
ularity as possible every milking, and
yet study of the test chart of any
COW ever tested will show variations
from day to day. Thousands Of cases
are on record where such cows very
carefully handled and an exactly
weighed food. will vary in test from
one day to another as much as one,
two or more whole percent.
There are great many causes sus-
pected of causing milk tests to vary
from day to day Some of the well
known causes for changes in tests
are:
1. Weather conditions invariably
affect both test and quantity, either
ore way or the other.
Q. A change in mixers. 8. Care
less or incomplete milking causes
change. ~ Sudden changes of any
kind S.. Physical condition of the
COW. A fat cow tests higher than a
thin COW for a month or longer when
first fresh. Ak COW in heat may test
very high or very low. s Under
! feeding A cow which does not have
enough to eat or is run down will
test below normal for long time.
7. Ill treatment decreases produc-
ton and test. 8. Period of lactation.
Test usually increases toward the
end of the milking period 9. She'd
ding hair seems to reduce test, in
whatever season it occurs. 10. Feed
No particular kind of feed has been
discovered which seems to permanent
ly increase the test, but well-fed COW
tests higher than a partly starved ami
NAL, a fat COW temporarily under-fec
tests higher for short time, anc
any change to-. a much better feee
which stimulates a heavy flow of milk
| (such as new pasture) usually re
duces test for while. A thin COW
when turned on new pastures, VII
test very low. II. Churned or 1eath
cry cream on milk delivered, caused
by lack Of proper cooling or stirring
on the farm, reduces test because {
correct sample cannot he obtained
IL. Taking off cream for home ust
will of course reduce test Each
cupful taken will reduce about Ont
PORT on 100 pounds of milk.
Test Of milk means the percentage
of butterfat which it contains. Per
centage means the number of part
per hundred. Thus a per. cent milk il
one which contains 5 pounds of but
terfat in each hundred weight of milk
Tie Babcock test is 'fool-proof
and always reliable. Sometimes tn
question is asked whether strong aci'
does not burn away or dissolve
] some of the fat in the cream sample
or milk samples, and thus lower tn
test. Acid can mot burn or dissolve til
fat in this test It has no effect on III
fat wtatsoevet as fat will float ur
harmed on any strength Of this acid.
L. w. TERNAHAN,
, Assistant County Agent