SPAH's technical service team answers questions about managing coccidiosis
Q. IS IT TRUE THAT THE USE OF THE COCCIDIOSIS VACCINE CAN RESTORE THE SENSITIVITY OF TRADITIONAL INFEED COCCIDIOSTATS?
A. Yes. In fact, when used over
time, the live oocyst vaccine actually
helps to convert resistant field strains to
strains that are more susceptible to traditional
The ability of the vaccine to restore the effectiveness of in-feed coccidiostats was demonstrated in studies conducted at the USDA. Oocysts were isolated from litter samples in houses with broilers that had been vaccinated for five flocks with Coccivac-B. Oocysts also were collected from litter in houses with non-vaccinated birds treated with ionophore coccidiostats.
Next, one group of specificpathogen- free (SPF) birds was challenged with oocysts from the vaccinated houses and another group of SPF birds was challenged with oocysts from the ionophore-treated houses. During the challenge, all birds received 60 ppm of salinomycin in the feed.
Comparison of the two groups revealed that isolates from the vaccinated houses were fully sensitive to salinomycin, while isolates from non-vaccinated houses varied in the degree of sensitivity.
In another trial, oocysts isolated from litter in a broiler house before immunization with the vaccine were compared to oocysts in litter from the same house taken after vaccination of one flock. Vaccination restored salinomycin sensitivity by seeding the house with coccidia that are sensitive to infeed coccidiostats.
Q. IN TERMS OF MANAGEMENT, WHAT CAN I DO TO OPTIMIZE PERFORMANCE OF A COCCIDIOSIS VACCINE?
A. There are several steps that producers
can take to optimize the performance
of coccidiosis vaccination.
Food and water given before or after vaccination should not contain anticoccidials or other drugs that could have anticoccidial activity. Oocysts provided by the vaccine could be destroyed, thus preventing the development of immunity.
Good sanitation is important because it reduces the chances that vaccinated birds will be challenged by coccidial organisms. We suggest removing litter and thoroughly cleaning houses in between rearing cycles.
Other management methods that can improve the performance of coccidiosis vaccination include lower bird density, breeding practices, controlling access to soil and reducing litter moisture. The litter used in houses should be absorbent, such as wood shavings or rice hulls. Straw does not absorb moisture well.
Q. WHAT STEPS SHOULD BE TAKEN IN THE HATCHERY TO ENSURE BEST RESULTS WHEN ADMINISTERING A COCCIDIOSIS VACCINE?
For starters, always follow proper
vaccine mixing procedures. This
includes following the manufacturer’s
mixing chart for correct amount of distilled
water to vaccine, using the correct
amount of dye (so you can spot
any missed birds), and maintaining
constant mixing of vaccine while it’s
being sprayed. Visually inspect the
Carboy bottle to make sure the vaccine
is being stirred.
You also want to make sure the vaccine is being properly administered. Conduct daily dosage checks and check the spray pattern on the chick box. If spray pattern from the nozzle is not even across box, remove the nozzle and clean or replace. Lastly, always let birds sit for 20 to 30 minutes in a lighted room before loading for delivery to allow them time to preen and dry.
[Note: If you suspect any problems, contact Schering-Plough Animal Health’s hatchery equipment department immediately at 800-531-0091 (U.S. only) or your local representative.]
Q. WHY DO COCCIDIOSIS VACCINES CONTAIN MORE THAN ONE SPECIES OF COCCIDIA?
A. Immunity to coccidia is species
specific. Therefore, immunity developed
against one species does not provide
cross protection against a different
species. For example, vaccinating or
exposing birds to only E. tenella over a
period of time will provide immunity or
protection only to further challenges
against E. tenella. In order to provide
broad protection against coccidiosis,
vaccines contain all the species considered
pathogenic to poultry.
Q. MY HATCHERY PRODUCES BIRDS THAT ARE DESTINED FOR MORE THAN ONE COMPLEX. IF I VACCINATE BIRDS FOR ONE COMPLEX, IS THERE A DANGER OF EXPOSING THE BIRDS DESTINED FOR THE OTHER COMPLEX WITH COCCIDIA FROM THE VACCINE?
A. There is no danger of creating a
problem with cross-contamination at
the hatchery. The complex not using a
coccidiosis vaccine will be using a coccidiostat
for coccidiosis control. Live
vaccine oocysts are highly sensitive to
anticoccidials, so even if 1-day-old
chicks are exposed to a full dose of the
vaccine by accident, the vaccine will be
eliminated by the coccidiostat in the
Q. DO I HAVE TO ROTATE COCCIDIOSIS VACCINES WITH ANTICOCCIDIALS?
A. No. Vaccines can provide yearround
protection without the buildup
of resistance associated with anticoccidials.
In broilers, some companies
choose to rotate the vaccine and anticoccidials
— perhaps three cycles with
vaccine, two with a coccidiostat — due
to cost (small birds) or to field-management
conditions that make vaccine
reactions more difficult to control in
Q. CAN COCCIDIOSIS VACCINE BE USED IN WINTER?
A. Yes. Coccidiosis vaccine can be
used in any season as long as moderately
dry litter conditions can be maintained
and stocking density can be
managed to control the vaccination
reaction. Some companies find it difficult
to use coccidiosis vaccine in winter
because ventilation is reduced and
birds are held in the partial house
longer than 14 days.
Source: CocciForum Issue No.4, Schering-Plough Animal Health.