The Manchester journal. [volume] (Manchester, Vt.) 1861-current, 1916-01-13
LOOK 0uT FOR OK
MARBLES IN CATTLE

Of Cattle Discovered in Northern
States. Native Species Long pest
in South. Reduces Milk Production
and Retards Growth Of Animal as
Well as Damaging Hide.
Washington, y. C., Jan. Special
lists Of the L. S. Department Of Agri-
culture are urging cattle owners, in
the North as well as in the South, TO
take steps % rid their cattle Of OK
warhles or wolves" the importance Of
which to the cattle industry has been
generally underestimated Ok MARBLES
are the whitish grubs or maggots
which develop from the eggs deposited
by certain flies known as warble flies or
heel flies and which injure he hides,
reduce milk flow, and retard growth
OF the animals The maggots are
commonly found just below the skin
on the backs Of cattle, in the spring.
Their presence is revealed by local
swellings about the size OF pigeons
eggs, each with small central hole or
perforation through which the maggo.
brcaths. From this hole the maggot,
when mature, emerges TO enter the
ground and change 20 the adult or fly
stage. When full grown the grub is
about three-fourths Of an inch in
length.
In the past trouble from the MARBLES
has largely been confined to cattle in
the South, but recently the Bureau Of
Entomology has discovered that sec
ond species, heretofore not found in
this country but known to be even a
more serious pest, in Europe, than is
our native warble, has become well es-
tablished in certain districts in the
northern part Of the United States.
While ii is probable that this so-called
European OK warble will not be Of as
great Importance in the Southern part
of the United States as .he species al
ready established, there is every reas-
on TO believe that unless checked it
will become generally distributed
throughout the northern half Of the
country. This European species is
now generally distributed throughout
New York and the New England
States, and few specimens have been
obtained from western Pennsylvania,
western Maryland, southern Michigan,
eastern Iowa and Missouri, and west
.ern Washington. Attention is also di-
rec.ed to the fact that this species is
now generally distributed throughout
southern Canada, The Department,
therefore, is calling attention at this
time to the danger of spreading this
species promiscuously abou. the coun-
try, and is urging cattle owners to
take the simple means necessary to
prevent its spread.
Warbles Tamage Hides, Reduce Milk
Production and Retard Growth
Until recently MARBLES were not re-
garded as serious even in the South
because i. was thought that the loss
they occasioned came principally from
the damage they did TO hides. Even
this loss in the aggregate, however, is
important, as hides show warble holes
three TO six months in the year and
dealers pay from so cents to S1.50 less
for hides that show even moderate
warble infestation. In many cases the
scars left after the holes have healed
cause buyers to cut prices consider
ably
The loss from the warble, however,
is by no means limited TO the holes the
maggots cut in the hides Extensive
Investigations in Germany and Dem
mark indicate tina. the losses through
reduction in milk supply in dairy cat
tie, the retardation Of growth in
young stock, and the loss Of flesh in all
classes of animals are twofold greater
than the damage done TO the hides |
In some Of these tests the early ex-
traction of the grubs from the backs |
of infested cattle resulted in an in
crease of nearly 25 per cent in the
milk production. Animals from which |
the grubs had been extracted showed |
a gain Of more than 5 per cent in
weight over similar animals in which /
.he pests were allowed to develop
normally.
Methods Of Controlling Marbles
Thus far the veterinarians and en-
tomologiest of the Departemnt have
determined no better way of controll-
ing these pests than through he sys-
tematic extraction and destruction Of
the grubs from the backs of infested 1
animals
When the larvae are nearly ready TO
leave the host they may be easily \
squeezed out by pressing the swelling
with the fingers, but If not so far de-
velopcd il is often very difficult TO get
them out by squeezing. In such cases
a slender pair Of forceps may be used