Monensin for the prevention of coccidiosis in calves


McDougald, L.R.

American Journal of Veterinary Research 39(11): 1748-1749

1978


Young calves (Holstein-Friesian) were inoculated with Eimeria bovis on the 3rd day after the start of 31 days' feeding of a ration containing added monensin in 2 dose levels: 16.5 g of 33 g/metric ton of feed. Monensin-treated calves were free of clinical signs of coccidiosis, but inoculated control calves developed diarrhoea and had excessive oocyst discharge on days 19 to 28 after they were inoculated. Weight gains and feed efficiency in monensin-treated calves were equal or superior to those factors in uninoculated control calves for the 31-day period.

Monensin
for
the
Prevention
of
Coccidiosis
in
Calves
L.
R.
McDougald,
PhD
SUMMARY
Young
calves
(Holstein
-Friesian)
were
inoculated
with
Eimeria
bovis
on
the
3rd
day
after
the
start
of
31
days'
feeding
of
a
ration
containing
added
monensin
in
2
dose
levels:
16.5
g
or
33
g/metric
ton
of
feed.
Monensin-treated
calves
were
free
of
clinical
signs
of
coccidiosis,
but
inocu-
lated
control
calves
developed
diarrhea
and
had
excessive
oocyst
discharge
on
days
19
to
28
after
they
were
inoculated.
Weight
gains
and
feed
efficiency
in
monensin-treated
calves
were
equal
or
superior
to
those
factors
in
noninoculated
control
calves
for
the
31
-day
period.
Despite
the
mounting
evidence
for
widespread
economic
loss
from
bovine
coccidiosis,'
there
have
been
few
drugs
developed
to
aid
in
treatment
or
prevention
of
the
disease.
Until
recently,
drugs
available
for
use
in
sheep
were
the
sulfonamides,
but
more
recently,
amprolium"
and
deco-
quinate
4
were
approved
for
use
in
cattle.
The
recent
success
with
monensina
used
as
an
anticoc-
cidial
agent
in
chickens'
and
its
subsequent
application
to
improvement
in
feed
utilization
in
ruminants
b
were
the
basis
for
the
present
experiment.
The
purpose
was
to
char-
acterize
the
effectiveness
of
monensin
against
bovine
coc-
cidiosis
caused
by
Eimeria
bovis
in
calves.
Previous
studies'
have
shown
that
continuous
feeding
of
a
drug
as
a
part
of
a
complete
feed
ration
is
an
effective
way
to
administer
anticoccidial
drugs
to
animals.
Materials
and
Methods
Experimental
Animals
and
Management
—Thirty-two
male,
Holstein
-Friesian
calves
were
obtained
at
1
to
3
days
of
age
and
fed
milk
replacer
until
weaning
(4
to
6
weeks
of
age).
Nonmedicated
cattle
ration
CA
-81
(Table
1)
was
fed
ad
libitum
until
initiation
of
the
test,
when
calves
were
6
weeks
old.
Calves
were
weighed
and
distributed
into
8
pens
of
4
calves
each,
to
contain
approximately
equal
pen
weights.
Two
pens
per
treatment
were
fed
CA
-81
ration
containing
monensin:
group
C,
16.5
g
of
monensin/metric
ton
of
feed,
and
group
D,
33
g/metric
ton
of
feed,
or
were
maintained
as
nonmedicated
controls
(groups
A
and
B;
Table
2).
Pine
shavings
were
used
as
bedding
for
the
calves
until
onset
of
oocyst
passage;
then
bedding
was
removed
to
allow
collection
of
the
daily
fecal
discharge
of
calves
on
a
pen
basis
from
the
concrete
-floored
pens.
Received
for
publication
May
4,
1978.
From
the
Lilly
Research
Laboratories,
Greenfield,
IN
46140.
Dr.
McDougald's
present
address
is
Department
of
Poultry
Science,
University
of
Georgia
College
of
Agriculture,
Athens,
GA
30602.
Rumensin,
Elanco
Products
Co,
Indianapolis,
Ind.
Raun
AP,
Cooley
CO,
Potter
EL,
et
al:
Effect
of
monensin
on
feed
efficiency
of
cattle
(abstr).
J
Anim
Sci
39:250,
1974.
Coccidial
Inoculum—Oocysts
of
E
bovis
were
obtained
from
an
outbreak
of
coccidiosis
in
a
cow
-calf
operation
near
Greenfield,
Ind.
Oocysts
for
use
in
the
present
study
were
obtained
by
collet.
tion
of
feces
from
an
experimentally
infected
calf
about
30
days
before
the
present
experiment
was
started.
Calves
in
groups
C
and
D
were
each
inoculated
orally
with
100,000
sporulated
oocysts
after
they
had
been
fed
the
experimental
diets
for
3
days;
group
A
calves
(nonmedicated)
were
given
the
same
dose
of
oocysts,
Data
Collection
—Calves
were
weighed
individually
at
the
time
of
inoculation
and
subsequently
once
every
7
days
until
the
end
of
the
experiment
at
postinoculation
day
(PID)
28.
Daily
fecal
collee-
tions
were
diluted
with
water
and
mixed
with
a
stirring
motor;
then
aliquots
were
counted,
using
a
McMaster
slide.
Total
daily
fecal
oocyst
output
per
calf
was
estimated
by
extrapolation
of
aliquot
counts
to
total
fecal
volume.
Results
Clinical
Observations
—Diarrhea
and
anorexia
occurred
in
the
2
pens
of
inoculated
control
calves
(group
A)
from
PID
12
through
21.
Untoward
effects
were
not
seen
in
the
other
groups
(groups
B,
C,
and
D).
Oocyst
Passage
—Substantial
oocyst
passage
was
re-
corded
on
PID
19
through
28
in
the
2
pens
with
inoculated
controls
(group
A,
Fig
1).
Oocysts
were
not
passed
by
group
D
calves
(33.0
g
of
monensin/metric
ton).
Oocysts
recovered
from
control
calf
pens
(group
A)
were
identified
as
E
bovis
on
the
basis
of
morphology.
Performance
of
Calves
—Weight
gains
of
inoculated
con-
trols
(group
A)
were
depressed
during
the
clinical
phase
of
coccidiosis,
particularly
notable
at
PID
21
(Table
2).
This
depression
was
reflected
in
a
total
average
weight
gain
at
PID
28
significantly
less
than
the
gain
in
other
treatment
groups
(groups
B,
C,
and
D).
Calves
treated
with
monensin
TABLE
1
—Cattle
Ration
CA
-81
Ingredients
Quantity
(kg/metric
ton)
Corn,
yellow
382
Rolled
oats
210
Beet
pulp
100
Linseed
oil
meal
solvent
100
Soybean
oil
meal,
solvent
extracted
dehulled
50%
62.5
Distillers
dried
solubles
(corn)
50
Molasses,
cane
70
Dicalcium
phosphate
10
Salt
(NaC1)
10
Trace
mineral
premix*
3.75
Vitamin
A
and
D2
premix
CK-Olt
0.80
Vitamin
E
0.50
Anticoccidial
secondary
premixt
0.90
*
Trace
mineral
premix
contains
2.50%
manganese
as
manganous
oxide,
0.07%
iodine
as
potassium
iodide,
0.30%
cobalt
as
cobalt
carbonate,
0.50%
copper
as
copper
oxide,
and
20%
zinc
as
zinc
sulfate.
t
Contains
4.4
x
10'
USP
units
of
vitamin
A
and
4.99
x
10
5
USP
units
of
vitamin
13
2
/0.45
kg.
Concentration
depends
upon
treatment.
1748
Am
J
Vet
Res,
Vol
39,
No.
j1
TABLE
2
-Experimental
Procedure:
Average
Body
Weight
Gains
of
Calves
Infected
with
Eimeria
bovis
and
Treated
with
Monensin
Treatment
and
exposure
Cumulative
body
weight
gain
(kg/calOt
Calf
group
(2
Treatment
with
monensin
(dos-
Initial
weight
of
calf,
6
pens/group)
age
in
g/metric
ton
of
feed)
Inoculated*
weeks
old
(kg)
Day
0
PID
7
PM
14
PID
21
PID
28
A
None
(controls)
Yes
53.55
3.9
9.18
14.32
15.68
21.68"
B
None
(controls)
No
60.14
3.66
8.86
14.09
20.09
25.77
.
C
16.6
Yes
54.50
4.82
10.86
17.68
23.14
28.45'
D
33
Yes
52.95
4.77
10.23
16.95
22.05
28.64'
*
100,000
sporulated
oocysts
of
E
bovis
inoculated
orally
after
3
days
on
experimental
diets.
t
Means
with
common
superscript
letters
are
not
significantly
different
at
P
5_
0.05.
PID
=
Postinoculation
day.
20
X16
0
j12
8
0
O
0(A)
CONTROL,
INOCULATED
(B)
CONTROL,
NONINOC.
(NOT
SHOWN)
-e(C)
MONENSIN,
16.5
G/T
(D)
MONENSIN,
33
G/T
(NOT
SHOWN)
15
17
19
21
23
25
27
DAYS
POSTINOCULATION
Fig
1
-Oocyst
passage
by
calves
inoculated
with
Eimeria
bovis
on
the
3rd
day
after
the
start
of
31
days'
feeding
of
a
ration
containing
added
monensin.
Data
are
shown
for
group
A
controls
(0
0;
nonmedicated
but
inoculated)
and
for
group
C
principals
(11-0;
treated
with
the
smaller
dosage,
16.5
g
of
monensin/metric
ton
of
feed).
Data
for
group
B
controls
(nonmedicated
and
noninoculated)
and
group
D
principals
(treated
with
33
g
/ton)
indicated
no
oocyst
passage
and
are
excluded
from
the
figure.
TABLE
3
-Performance
of
Calves
Infected
with
E
bovis
and
Treated
with
Monensin
Calf
group
A
(control,
inoculated)
B
(control,
noninoculated)
C
(monensin,
16.5
g/ton)
D
(monensin,
33
g/ton)
Total
gain/calf
(kg)*
21.70'
25.79'
28.49'
28.64'
Feed
consump-
tion
(kg/calf)*
64.90
71.50
70.46
70.14
Feed/gain*
3.00
b
2.77'"
2.48'
2.45'
Total
oocyst
production
(X1(r)*
58.7
0
Tr
.
0
*
Average
of
2
replicates
per
treatment.
Means
with
common
superscript
letters
are
not
significantly
different
at
P
<
0.05
(Duncan's
multiple
range
test).
Tr
=
Trace;
positive,
but
too
few
to
count.
at
both
dose
levels,
16.5
or
33
g/ton,
had
the
highest
total
gains
(28.49
and
28.64
kg,
respectively),
with
no
evidence
of
any
influence
of
the
parasitic
inoculum
on
gain
(Table
3).
Feed
consumption
of
inoculated
controls
was
depressed
during
the
clinical
phase
of
infection,
and
the
overall
feed:gain
ratio
was
higher
(Table
3).
Noninoculated
control
calves
and
monensin-fed
calves
consumed
approximately
equal
amounts
of
feed,
resulting
in
better
feed:gain
ratios,
since
gains
were
also
better
in
those
groups.
Discussion
Control
of
E
bovis
infections
in
calves
by
feeding
mo-
nensin
at
dose
levels
of
16.5
or
33
g/metric
ton
of
feed
was
excellent
under
the
conditions
of
the
present
experiment.
The
effectiveness
of
monensin
at
the
2
dosages
when
mixed
into
a
complete
feed
ration
is
especially
important,
since
similar
levels
are
approved
for
use
in
improvement
of
feed
utilization
in
beef
cattle.
These
results
agree
generally
with
those
of
Fitzgerald
and
Mansfield,'
who
found
that
monen-
sin
in
pelleted
feed
protected
young
calves
against
E
bovis
infections
when
the
drug
was
given
at
the
rate
of
0.25
mg
or
more/kg
of
body
weight.
Prophylactic
use
of
anticoccidial
drugs
in
cow
-calf
op-
erations
and
in
young
growing
calves
is
not
generally
prac-
ticed.
In
many
instances,
however,
young
calves
are
at
greatest
risk
from
coccidiosis;
Fitzgerald'
reported
that
56%
of
cattle
producers
surveyed
believe
that
there
is
a
need
for
a
prophylactic
drug.
Treatments
in
use
included
sulfon-
amide
drugs,
nitrofurazone,
amprolium,
and
various
other
unproved
drugs
or
compounds.
The
availability
of
a
reliable
drug
with
good
efficacy
makes
the
concept
of
preventive
medication
for
coccidiosis
useful
and
economically
attrac-
tive
as
a
veterinary
management
tool
in
the
cattle
industry.
References
1.
Fitzgerald
PR:
The
economics
of
bovine
coccidiosis.
Feedstuffs
44:28,
1974.
2.
Jolley
WR,
Hammond
DM,
Miner
ML:
Amprolium
treatment
of
six-
to
twelve
-month
-old
calves
experimentally
infected
with
coccidia.
Helminthol
Soc
Wash
38:117-122,
1971.
3.
Slater
RL,
Hammond
DM,
Miner
ML:
Eimeria
bovis:
Develop-
ment
in
calves
treated
with
thiamine
metabolic
antagonist
(amprolium)
in
feed.
Trans
Am
Micros
Soc
89:55-65,
1970.
4.
Decoquinate:
As
an
aid
in
the
prevention
of
coccidiosis
in
rumi-
nating
calves
and
cattle
caused
by
Eimeria
bovis
and
E.
zurnii,
in
Feed
Additive
Compendium.
Minneapolis,
Miller
Publishing
Co,
1978,
p
206.
5.
Reid
WM:
Progress
in
the
control
of
coccidiosis
with
anticoccidials
and
planned
immunization.
Am
J
Vet
Res
36:593-596,
1975.
6.
Reid
WM:
Coccidiosis,
in
Hofstad
MS,
Calnek
BW,
Reid
WM,
et
al
(ed):
Diseases
of
Poultry,
ed
7.
Ames,
Iowa,
Iowa
State
University
Press,
1978,
p
800.
7.
Fitzgerald
PR,
Mansfield
ME:
Efficacy
of
monensin
against
bovine
coccidiosis
in
young
Holstein
-Friesian
calves.
JProtozool
20:121-126,1973.
8.
Fitzgerald
PR:
The
significance
of
bovine
coccidiosis
as
a
disease
in
the
United
States.
Bovine
Pract.
November,
1975,
pp
28-33.
November,
1978
1749