Fringe benefits
Coccidiosis remains
widespread in the EU and
elsewhere, reportedly costing
producers €2 billion (US $ 2.9
billion) annually — more than
any other disease.
DR. LUCIANO GOBBI
Besides keeping the disease in check,
coccidiosis-vaccination programs can
help producers restore the sensitivity of
in-feed anticoccidials; they can also
complement the practice of thinning
flocks and enhance marketing, reduce
costs, simplify work at the feed mill and
improve food safety, Dr. Luciano Gobbi,
a veterinarian and technical service
manager with Intervet/Schering-Plough
Animal Health, said at VIV Europe
2008 — Moscow Edition.
The primary means of controlling
coccidiosis has been in-feed anticoccidials,
which accounted for 87% of coccidiosis
control in the EU, according to a
2007 report. Yet coccidiosis remains
widespread in the EU and elsewhere,
reportedly costing producers €2 billion
(US $2.9 billion) annually — more than
any other disease — primarily due to lost performance that results from subclinical
coccidiosis, said the Italy-based Gobbi.
One of the main problems with
anticoccidials is the development of
coccidial resistance, which has resulted
from the overuse of the products, he
said. Gobbi cited studies from the US,
South America, Germany and the
Netherlands documenting resistance.
In the Dutch study, for instance, testing
of 15 Eimeria isolates showed that 78%
were resistant to diclazuril, 72% were
resistant to monensin, 68% were resistant
to nicarbazin and 64% were resistant
to salinomycin.
Vaccine benefits
A major benefit of coccidiosis
vaccination, he said, is the restoration of Eimeria sensitivity, which can be
accomplished by rotating a vaccine with
anticoccidials. Gobbi showed an example
demonstrating that in flocks where
ionophore sensitivity had declined, the
use of the coccidiosis vaccine Paracox-5
for three consecutive flocks restored
ionophore sensitivity.
“One hypothesis is that vaccinal Eimeria
lines conjugate with wild lines and render
Eimeria strains less pathogenic and more
sensitive to anticoccidials. Conjugation
means an exchange of genetic material,
leading to less pathogenicity and a
restoration of sensitivity to anticoccidial
drugs,” he explained.
In trials designed to assess bird
performance when a coccidiosis vaccine
was rotated with anticoccidials,
performance was within the normal range, whether the birds were light or
heavy, although the best results were
achieved in heavy birds raised to 2.0 kg
or above, Gobbi said.
Compensatory growth occurred by day
30 onwards and performance improved
with continuous vaccination of successive
flocks because the challenge of natural
coccidiosis declined. In addition, good
results were achieved when flocks
returned to in-feed anticoccidials, he said.
Enhances thinning
Continuous use of a coccidiosis vaccine
not only provides complete control of the
disease, it also can enhance the practice
of flock thinning, Gobbi said. With
thinning, male and female birds in one
house are divided by a barrier. For the
first thinning, females are usually removed
and the barrier is taken away, leaving the
whole house to grow larger males.
Thinning also makes it easier to grow
heavy birds in hot summer months.
Coccidioisis vaccination complements
thinning because there is no anticoccidial
drug in the feed and, consequently, no
withdrawal time, which enables producers
to pull light or heavy birds as needed to
meet market demand, he said.
“Vaccination makes it easier to thin flocks,
which in turn helps increase meat production
per square meter,” Gobbi explained.
With more birds raised in the same house,
costs are reduced for transporting feed
and for moving chicks to the house and
transporting them to market. In fact,
transportation costs can decrease by as
much as 20% to 30%, he said.
Since integrators pay farmers on the
basis of kg of meat per square meter, which is improved with coccidiosis
vaccination, farmers have reduced fixed
costs, while integrators have a reduction
in variable costs. “Hence, the integrator
has reduced remuneration to farmers per
kg of meat produced by each square
meter,” Gobbi said.
Life at the feed mill is simplified, too,
with coccidiosis vaccination, he said.
There is no need for cleaning the
manufacturing lines and equipment to
reduce or prevent the unwanted carryover
of anticoccidials, Gobbi said.
Another important benefit of coccidiosis
vaccination is the reduced risk for drug
residues in broiler meat that can result
from the use of anticoccidials or therapeutics
administered when coccidiosis outbreaks
occur.
“Consequently, finished-meat products
are from a traceable, clean production
chain and can be guaranteed as safer for
consumers,” he said. “This is particularly
important for producers growing drugfree
birds who want to differentiate
their product.”
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