The Sauk Centre herald., 1911-05-25
HOG CHOLERA---NO. !.
BY Dr.. M. II. Reynolds, Mime.
sofa University Farm.

j. i. !. + i. j. i. i. = i. j. !. + !. !: !. :.
Farmers ought to understand the
two methods of protecting susceptible
hogs. by vaccination, against cholera
Experimental work has been under
way at the Minnesota Experiment Sta
tioD since November. 1907. Such work
has been under way still longer in the
Federal Bureau of Animal Industry,
| very greatly to the credit of Doctors
Dorset and Niles. who have had
charge of the government work.
We can say to farmers that this
hog-cholera vaccine work has pro-
gressed to point where we have an
established method of producing a
I serum capable of giving ample pro.
lection. We can vaccinate hogs and
make them absolutely immune to
cholera, when the serum is intelli,
gently and fairly used according to di.
rections
The two methods of vaccination we
know as "serum-onIy" and "sinuItan.
eous." Serum-onIy vaccination con-
sists of injection, under the skin. of
blood serum taken from a hyper-im-
mune hog, as explained in Hog-Chol-
era Article No. g. Such treatment
gives immediate but very temporary
immunity. But if the treated hog is
soon after vaccination exposed to pen
infection with sick hogs, or given an
incubation with virulent blood from a
hog sick with cholera, it then be.
comes immune for long period, per-
haps for life.
The second method, which l called
simultaneous vaccination. consists Of
an injection of protecting serum under
the skin of one thigh; and, immediate.
ly afterwards, an injection of serum
from a sick hog under the skin of the
other thigh. BY this process we give
the susceptible hog the disease, and
at the same time give him something
which enables him to resist the infec-
ton. The hog IL then presumably in
about the same condition as though he
had gone through an outbreak of chol,
era and recovered. Everybody knows
that hogs which have gone through
outbreaks are usually immune for life
Vaccination by the serum.onIy
method gives instantaneous immunity.
Protection under the simultaneous
process is supposed to come a little
slower. but lasts very much longer.
We usually consider about two weeks
as necessary for the vaccination pro-
cess to be completed under the stimuli
taneous method.
Experience is accommodating which
shows that the death rate is not larg-
err when apparently well hogs in re-
cently-infected herds are given the
simultaneous vaccination, than when
such hogs are given serum only. The
double vaccination has the advantage
of permanent protection For the
present, we are generally advising the
serum-only method for use iI herds
where the disease has very recently
appeared. Our serum should not be
used at all in any herds where the
disease has not very recently ap-
peared.
There is no risk whatever from the
serumonly vaccination; but the mere
catching ind undue disturbance of
hogs that have been infected with
cholera, and are more or less feverish
sometimes results in hurrying the
case, Such hogs may die within ten
or twelve hours; when, without such
undue chasing and handling, they
might have lived for several days IN
such case owners usually blame tie
serum Such hogs would have died
just tbs same If they had been ii
jected with water, or had been chased
and handled and not injected at all
During the. past year. at the station.
we have produced about $500 doses Of
serum and only one batch of the en-
tire lot has failed to prove potent un.
der actual trial.
Our field results during the past
year have been very satisfactory.
Several disappointment in connection
with the use of our serum have been
reported 1t has been our policy TO
send an assistant to investigate such
cases; partly for, the purpose of show
ing the local people, for their own fl.
ture benefit, wherein the trouble lay
The next article will undertake to
present the causes and explanations
of disappointments in connection With
the serum, and to define the con1i
tions under which the serum is
tributed.