COCCI FAQs
Schering-Plough's tech service team answers questions about managing coccidiosis in broilers.
Q. AFTER USING COCCIVAC-B
OR PARACOX-5 ONE OR TWO
TIMES, ARE THERE ENOUGH
OOCYSTS IN THE LITTER TO STIMULATE
NATURAL IMMUNITY
WITHOUT VACCINATION OR WITH
A REDUCED DOSE?
A. No. While it's true that
oocysts are in the litter, reliable
immunity will only be achieved
by giving each bird a controlled,
balanced dose of Eimeria organisms
through vaccination to all new flocks.
Q.WHAT IS THE EFFECT OF IN-FEED ANTICOCCIDIALS
ON BIRDS THAT HAVE BEEN
VACCINATED AGAINST COCCIDIOSIS?
A. If in-feed anticoccidials are used
before Eimeria organisms become
established, the number of oocysts
replicating in birds can be reduced significantly.
The result will be less than
optimal immunity against coccidiosis.
Q.IF CHICKENS COME FROM TWO
SOURCES AND SOME ARE VACCINATED
AND SOME ARE NOT, WHAT DO
YOU DO?
A. Go back and revaccinate. An
alternative would be to vaccinate
just the birds that had not been vaccinated
earlier, even if this requires
segregating and confining those
birds for a day or two in a small
area. Then they could be mixed
with the rest of the bird population that
was already vaccinated.
Q. IS VACCINATION WITH COCCIVAC-B
OR PARACOX-5 EFFECTIVE ON FARMS
THAT ALREADY HAVE COCCIDIOSIS OR
WHEN THERE ARE HIGH LEVELS OF
OOCYSTS IN THE LITTER?
A. Yes. If birds are vaccinated on day
1, the organisms established during the
first week of life tend to take up residence.
These infections do not prevent
or eliminate wild oocysts in the environment
that affect chickens, but
oocysts from the vaccine tend to dominate
early infections. Thus, the impact
of wild oocysts isn't as severe.
Giving birds the initial exposure is
very critical because the subsequent
exposure will be less severe. If nonvaccinated
birds are, say, 10 days old,
and they're just getting their initial
exposure to wild coccidia through
ingestion of organisms, the amount
they get is uncontrolled. With vaccination,
that first exposure is controlled.
That's why we advise hatchery vaccination
on the first day for Coccivac-B and
Paracox-5, because it allows birds in
your system to start responding to the
antigen.
Q. DOES THE TYPE OF LITTER MATERIAL
INFLUENCE VACCINATION WITH
COCCIVAC-B OR PARACOX-5?
A. The quantity probably has more
impact than the type of material. We've
seen coccidia in all types of litter. The
thicker the depth of the litter, the more diluted will be the fecal matter, and the
reverse is also true. It is best to have a
thick, rather than thin, layer of litter.
Litter material should be high capacity
to absorb humidity.
Q.IF YOU ARE USING COCCIVAC-B OR
PARACOX-5 AND WANT TO SWITCH TO
ANTICOCCIDIALS, WHAT KIND OF ANTICOCCIDIAL
PROGRAM IS NECESSARY?
A. Based on our experience, any of
the anticoccidials should work if you
use the vaccine long enough, because
the organisms from the vaccines are
sensitive to several anticoccidial drugs.
Q. IS THERE A BEST TIME OF YEAR TO
USE COCCIVAC-B OR PARACOX-5?
A. The vaccines can be used at any
time of year. There is a producer in the
Southeast United States and several
companies in Europe that have been
using the vaccine year-round for several
years with excellent success. The key
is proper management of factors such
as bird density and litter moisture.
Q.WHAT ARE THE PROS AND CONS
OF THE MAJOR IN-FEED ANTICOCCIDIALS
FOR SHORT- AND LONG-TERM
COCCIDIOSIS CONTROL?
A. Chemical or synthetic anticoccidials
are highly effective when they're
first used.
Unfortunately, Eimeria organisms
can develop resistance to them fairly
quickly, so you can use them only for
one or two cycles.
Resistance is also a problem with
ionophore antibiotics, but it appears to
happen more quietly and gradually. In
some ways, however, that can
be more costly than a total
product failure because the production
losses are not as apparent,
even though they may still
be significant.
Rotating ionophore antibiotics
can help slow this resistance,
but the impact may be
minimal because the ionophores
are all similar compounds
and there is cross-resistance
among them; that is,
strains of coccidia that become
resistant to one ionophore drug
may become resistant to others as well.
Vaccinating for coccidiosis for three
or four cycles can help break up the
cycle of resistance and restore sensitivity
to in-feed anticoccidials.
Q. WHY DON'T I SEE ANY CLINICAL
SIGNS OR IMPAIRED PERFORMANCE AS
A RESULT OF LEAKAGE AND RESISTANCE
IN AN IONOPHORE PROGRAM?
A. You are seeing impaired performance,
it's just not being quantified.
Impaired performance due to leakage
"when some Eimeria oocysts survive
initial treatment and then begin to
multiply and reinfect birds "is
not always revealed by the
benchmarking methods used by
some poultry companies. If
impaired performance is related
to E. maxima late in the grow-out,
there may be no clinical signs, but
there will be microscopic evidence
of subclinical coccidiosis.
Unfortunately, many producers
don't see the shortfall in performance
until they switch treatment
methods and experience a
performance gain. Poor performance
due to leakage and resistance
often improves with vaccination, which initiates early coccidial
cycling, helps build immunity and lowers
the oocyst carryover load in subsequent
flocks.
Q. WILL SHUTTLING IN-FEED ANTICOCCIDIALS
"FOR EXAMPLE, USING A
CHEMICAL IN THE STARTER PHASE AND
AN IONOPHORE ANTIBIOTIC IN THE
GROWER PHASE "REDUCE RESISTANCE
TO IN-FEED ANTICOCCIDIALS BETTER
THAN SIMPLY ROTATING PRODUCTS
WITH EACH FLOCK?
A. No. The more often you put an infeed
anticoccidial product in front of
Eimeria organisms, the more potential
there is for resistance to develop. The
unfortunate part of a shuttle program is
that you can develop resistance to
anticoccidials.
Q. AFTER REPEATED USE OF
COCCIVAC-B OR PARACOX-5, CAN I
START VACCINATING WITH A HALF-DOSE
SINCE THE POULTRY HOUSE IS NOW
SEEDED WITH OOCYSTS FROM THE
VACCINE?
A. Definitely not. It is critically
important to use a full, controlled dose
to ensure uniform distribution. Halfdosing
increases the risk that some
birds won't get enough of the vaccine
and some may not get any.
Unvaccinated or inadequately vaccinated
birds will not experience oocyst
cycling or develop immunity at the
same time as vaccinated birds, and they
can develop significant reactions upon
exposure to coccidia. In addition, there
is a balance between different Eimeria
species; a certain number of one
species "say E. acervulina "helps
reduce the multiplication of another
species "say E. maxima.
If a half-dose is administered, this
balance can be disrupted and uneven
multiplication of Eimeria parasites may
occur.
Q. WHY AREN'T MORE COMPANIES
USING COCCIVAC-B OR PARACOX-5 IF
IT'S SO GOOD?
A. Vaccinating for coccidiosis represents
a big change in the way that
poultry companies have controlled coccidiosis.
Coccivac-B and Paracox-5
have been shown to be effective and
safe products. In fact, industry data
show that when live performance is
measured, the vaccine is comparable, if
not better, than standard in-feed anticoccidial
programs
However, it's difficult to convince
people to try something new; that's the
reason more companies haven't yet
switched to Coccivac-B or Paracox-5.
So far, many innovative companies
have successfully adopted Coccivac-B
or Paracox-5 as part of the their long
term anticoccidial strategy. As more
companies recognize the losses associated
with ionophore oocyst "leakage,"
they will likely adopt vaccination.
Source: CocciForum Issue No.11, Schering-Plough Animal Health.
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