Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1921-11-19

here presented figures to substantiate
the conclusion.
"These results are applicable to
most dairymen in the State for it
may be shown that the average S
months milk yield, cows two years
old, is 371O pounds. If we can in
crease the milk yield of our cattle
even the lowest per cent, 81 per
cent, by the use of bull from a
good producing strain It is well worth
our while.
It now becomes vital for our study
to determine what part heredity,
feeding and care and unknown
other factors influence milk yield
and butter-fat percentage. BY ap-
propriate methods it is possible to
show that, for Holstein- Friesian ad-
vanced registry cattle, heredity de-
termines 73 per cent. of their pro-
duction, feeding and care II per
cent. and unknown influences 16 per
cent. For a pure bred herd Of Jer-
sey cattle bred within island lines
and kept under the same conditions
heredity determined 30 per cent,
feeding and care ii per cent. and I'M
known factors SO per cent. Of the
cows milk yield. The cows butter
fat percentage in the Holstein- Fries
ian advanced registry is determined
to the extent Of about 20 per cent. by
heredity and 10 per cent. by feeding
and care and 20 per cent. by un-
known factors. In this pure bred
herd of Jerseys heredity determines
Oh per cent, feeding and care one
per cent. and unknown factors Al
per cent of the cows butter-fat per-
centage. The same relative compari-
son holds for the other breeds.
These factors are we'll worth con-
sideration. Feeding and care play
approximately the same part in de-
termining the production of the COW
in both the advanced registry cattle
and in the pure bred herd, what is
the explanation OF the difference in
the part played by heredity? Our
present knowledge of breeding indi-
Gates the explanation. Within any
herd under the systems of breeding
normally carried on there is nat
ural collecting together Of the fac
tors responsible for the inheritance
OF milk yield. This gradual collection
of these factors and consequent
purifying Of the herd, cause the cs-
Enlistment of certain level of milk
yield around which the. cows vary.
This level of milk yield can only be
broken by the bringing in Of other
IN rff IL a. 81
herd is very high it is, of course, not
desirable to bring in these outside
factors as it is more likely than not
that the milk yield of these cows will
be reduced rather than increased.
On the other hand If the milk yield
of the cows is low it is essential to
buy in other cows or bulls and thus
bring in other factors. AS the re-
suit of the experiment above de-
scribed indicates, great care should
be taken to get this bull from lines
known to be high in production, for
only by so doing can the production
be increased. For the breeder whose
herd is medium producing one, the
task is harder. He must always Sc
lect a sire whose transmitting ability
for milk yield is higher than that Of
his own herd. How can this be done?
The advanced registries Of the differ
ent herd association at present offers
our only source of information from
which to select bulls. But this in
formation is not in an easily access
ible form because of age difference in
the cows, etc. Here again these
animal husbandry Investigations
have presented an analysis OF these
data in such a form as to be readily
disable in practical work. Thus in the
progeny performance studies of the
Jersey and Holstein- Friesian breeds
it is easily seen that Chief Engineer
for the Jersey and King Segis Pom
tiac Count are two most excellent
bulls probably capable Of increasing
the milk yield Of almost any herd. Il
The address was illustrated by
lantern slides showing each point.