Montana farmer-stockman. [volume] (Great Falls, Mont.) 1947-1993, 1956-06-01
Veterinary
Veterinary
.JOhne's Disease
TO Be Watched
By STUART YOUNG, D.V.M.

to Stock-raiSerS in the northwestern
United States, Johne's disease continues
to be an increasing threat to world beef
and dairy cattle populations. Great ex-
pense and considerable efforts are
directed at the control or eradication
of this disease in Europe, Canada, South
America, North, West and South Africa,
Iceland, India and New Zealand. 1t is
growing problem in Australia, Tas-
mania and East Africa.
In the United States, the extent of
the damage done by this disease is still
not fully known. AS long ago as 1924
an American author prophesied that
Johne's disease, without effective con-
troll, could become a greater scourge
for future generations than tuberculosis
of cattle was for those past. The 1912
Yearbook of Agriculture quoted the be-
lief of veterinarians that the disease
was spreading and could become as
serious in the United States as it is in
Europe. This report estimated the ami
NAL financial loss to agriculture as
half million dollars. AS recently as
1851 one author has claimed that the
death-rate in America might be as high
as 10 per cent of adult cattle stock,
with an overall animal loss of about
8 per cent.
Known for 200 Years
JOhne's disease has been known to
exist for nearly 200 years. 1t is particu-
larly prevalent under temperate eli
mates and especially damaging in in
tensive dairying areas. 1t also occurs
in wet, humid areas of the tropics but
is almost unknown where the climate
is hot and dry.
JOhne's disease is chronic, insidious,
infectious disease caused by the multi
plication of a germ, related to that
which causes tuberculosis, in the intes-
tine and related glands. Almost always,
infection occurs in the young animal in
calfhood but, because the incubation
period is very long, symptoms usually
only appear in cattle 8 to years old.
An intermittent or persistent diarrhea
occurs, the coat becomes rough and
fades in color and great loss in condi-
ton occurs before death results.
1t has recently Q949) been shown
that, in an affected cattle population,
Is to II per cent of the cattle may
carry the infection without showing any
sign of disease. The feceS of these car
rier animals, as well as those of sick
animals, pour out the responsible germs
in vast numbers. These germs can live
on pastures for more than six months
and still be dangerous to calves.
Calves Born With Disease
One other disturbing fact about the
disease has also recently been I'm
cOvered-a calf born from an infected
carrier can itself be infected before
birth. 1t has always been hoped that
the damage done by this disease could
be reduced by raising dairy calves in
isolation from adult cattle, but a calf
born with the disease can spread it to
other calves in its feceS.
Usually the disease is brought into a
herd or district by bringing in cattle
infected with the germ but not showing
symptoms. The infected feceS from
these cattle contaminate pastures, wa
ter and feed and calves pick up the
infection. Whether symptoms are ever
shown or loss in condition occurs de-
ponds on other factors that may lower
the animals resistance. Such factors as