Studies show light and color can impact coccidiosis vaccine performance
Sometimes, nature really does
know best. And in a modern
hatchery vaccinating birds for
coccidiosis, light and color can be
important tools for maximizing distribution
of vaccine oocysts and ensuring
broad protection.
Since it was launched in late 1997,
hatchery spray administration of
Schering-Plough Animal Health’s coccidiosis
vaccine lines, Coccivac and
Paracox, has proved to be a fast, inexpensive
and effective way to immunize
broilers, breeders and layers against
coccidiosis.
Unlike other spray-administered
vaccines that enter the birds’ system,
either through the eye or respiratory
tract, coccidiosis vaccine must be
ingested for an optimal intake and colonization
of the intestinal tract. While
the spray cabinet method is undoubtedly
effective, understanding why
it is effective — what stimulates
the chicks to preen
and ingest the vaccine
they’ve sprayed with
— is an extremely
useful hatchery-management
tool.
A series of three trials
carried out at Texas
A&M University provided
some important
insights, and
shows that natural
responses of chicks can be harnessed
to ensure optimal uptake of
spray cabinet-administered vaccine.
The research1 published in 2001, was
supervised by Drs. Billy Hargis and
David J. Caldwell, faculty members of
the Departments of Poultry Science
and Veterinary Pathobiology at the
university.
Conducted under laboratory conditions,
the first trial looked at the effect
of manipulating sound, temperature
and light. While changes in all three
stimuli could be manipulated to
increase preening behavior, changes in
light levels, or photointensity, made the
biggest impact.
Caldwell says the responses of the
chicks were very much as expected,
given what is known about their
behavior.
Changing ambient sound levels
from 83 dB before spraying to 56 dB at
spraying and for 5 minutes following
had the effect of increasing the amount
of preening. So too did increasing the
temperature from 20°C (68°F) before
spraying to 35°C (95°F) during spraying
and for 5 minutes after the vaccine had
been applied.
Under commercial conditions, controlling
levels of sound and temperature
like this may not be practical.
However, changing lighting conditions
— an easier practice for most
hatcheries — gave the most marked
response.
Aviagen puts photointensity results into practice
Aviagen’s Dr. Stanley: Introduction of lighting
to encourage vaccine uptake well worthwhile.
‘The results have been positive.’
Aviagen, a leading poultry breeder based in Huntsville,
Alabama and Newbridge, Scotland, has successfully captured
the benefits identified by Texas A&M University’s
preening behavior
research in its coccidiosis
vaccination
program.
The company, which
supplies broiler breeder
chicks to more than 85
countries worldwide,
routinely vaccinates
day-old chicks with
Coccivac. Quick to see
the advantages of the
spray cabinet system,
Aviagen introduced
spray cabinets about 5 years ago — for the application of
Coccivac-D.
Dr. Bill Stanley, director of Quality Assurance for Aviagen,
says the technology applied to coccidiosis vaccination fits
well with the company’s drive for system-wide standardization.
Aviagen achieved ISO 9001 registration (the international
standard for quality management systems) in June
2005.
Stanley says the company successfully applied Texas
A&M’s findings to its own hatchery operations during
February and March 2004, and the use of increased lighting
has been established for about a year.
“We haven’t done any external trials to quantify the success
of introducing increased lighting, but internally, the
results have been positive,” he says.
“You can see an increase in preening activity under the
intense lighting, which improves uptake and distribution of
the coccidiosis vaccine.”
Applying the results from lab-based trials into a large-scale
commercial operation took some working out, Stanley
says, but ultimately the solution was fairly straightforward.
“We developed a system of rollers in a series long enough
to accommodate about 10
boxes of chicks at a time,”
he explains. “The rollers are
on a slight decline, so the
operator doesn’t have to
force them through. There
are fluorescent lights over
the rollers, and the chicks
are exposed for about 6 minutes
after they’ve been in the
spray cabinet.”
Precise levels of photointensity
aren’t crucial, but as a general rule, the chicks would be
exposed to about the same illumination found in a welllighted
office — perhaps around 1,000 lux (93-foot candles).
Stanley cautions: “Spreading the chick boxes out during
the 6-minute period should be done in an area free of
drafts to avoid chilling of chicks.”
Introducing fluorescent lighting to enhance preening and
vaccine uptake has been a success for Aviagen, Stanley
concludes. “The improved preening response, and
improvements in vaccine uptake, have made the change
well worthwhile for us.”
In the first Texas A&M trial, photointensity
was increased from 0 lux
(complete darkness) to 1,243 lux
(115.5- foot-candles) — about the same
level as a mechanic’s workshop or
operating room — at the time of spraying.
This lift in photointensity tripled or
quadrupled preening events. The trial
showed that a brief period of total
darkness (less than 2.5 minutes) followed
immediately by spray application in a strong light and maintained for
a period afterward, can have very positive
effects on preening behavior.
But conversely, putting chicks into
dark conditions straight after spraying
could have the reverse effect. In commercial
hatcheries, where trays of
chicks could be stacked straight after
vaccine spraying, this is possible. This
could lead to decreased preening activity
and a consequent reduction in vaccine
ingestion.
Other studies, conducted under
commercial hatchery management conditions, have evaluated other photointensity
regimes that could be implemented
more easily in a day-to-day setting.
Encouragingly, these trials have
shown that it may not be necessary to
put the chicks into total darkness prior
to spraying.
This is consistent with the second
Texas A&M University trial, in which
chicks were taken from normal hatchery
light levels of around 215 lux,
exposed to a 15-second burst of intense
light (3,226 lux) during spray vaccination,
and then held in elevated light
levels of 1,075 lux for a period postspraying.
Preening activity was doubled
in this trial.
Interestingly, this study also showed
that if the 15-second period of intense
light (created in the trial with portable
halogen lights) was prolonged, the
increased preening effect was lost. This
was probably because the warming
effect of the strong light made them
sleepy, overwhelming the “wake-up”
stimulus of the short burst of intense
light.
Of course, day-old chicks aren’t
only responsive to light. Color plays a
big part in their behavior, and the recommended
practice of adding coloring
agents to sprayed vaccine is well
established. Not only does the color
encourage preening, it also acts as a
useful marker to confirm birds have
been vaccinated.
Caldwell says a third Texas A&M
trial looked at the impact of color on
preening behavior. Colors throughout
the spectrum, including fluorescents,
were tried under a constant 990 lux
before, during and after spraying.
The addition of colors under constant
light levels stimulated a 2-fold to
3-fold increase in preening. Blues and
greens showed the strongest effects,
but the red used in the study (approved
for use in Paracox-5 as Cochineal E120)
was comparable, Caldwell says.
The light source (fluorescent versus
incandescent) made no appreciable difference
to the preening activity when
different colors were being trialed.
Probably the most significant finding
was that when coloring agents
were added to the spray under conditions
of increasing photointensity, it
made no difference to the increase in
preening behavior made possible by
light alone.
That finding is a very important one
for commercial hatcheries. It shows
there is real flexibility when it comes to maximizing the uptake of coccidiosis
vaccines applied using a spray cabinet:
• Where use of coloring agents in
spray cabinet vaccination is established
as part of the routine, these
trials show that the preening activity
will be enhanced, even under constant
lighting.
• Where use of coloring agents is not
practiced, then manipulation of photointensity
alone can stimulate
preening to a level even greater
than that achieved through coloring
agents.
• Where a coloring agent is regularly
used in combination with increased
photointensity during and following
spray cabinet vaccination, preening
activity and vaccine intake are still
enhanced.
Turning up the lights can do more than increase the uptake of spray-administered
coccidiosis vaccine.
An Italian trial, looking at the effects of different light intensities during
the first 4 days of life on the productivity and health of broilers vaccinated
with Paracox-5, also showed several performance benefits from elevated
light levels. By 49 days, the group raised in higher light levels to day 4
showed superior early growth rate, livability and flock uniformity. They
also showed lower overall mortality and reduced incidence of intestine
bacterial overgrowth.
Although it is too early to translate these trial results into firm recommendations
for producers, the research underlines the importance of light levels
for behavior and productivity.
This Italian trial, showing the benefits of correct light intensity in the first
few days of life for birds vaccinated against coccidiosis, confirms earlier
Schering-Plough research into the relationship between intestinal health
and management.
This fits with the Quadrants of Performance concept, developed by
Schering-Plough’s Technical Services team. (See article, page 8.) The concept
has been widely accepted by the industry as proving the importance
of developing early and predictable immunity, allowing the birds to express
their maximum potential for growth and feed efficiency.
On the other hand, without the protection of vaccination, late intestinal
challenges — a consequence of poor drug efficacy or resistance —
can compromise performance and profits.
Using light intensity with spray cabinet vaccination, leading to an adequate
vaccine uptake, will favor the establishment of early immunity with all the
benefits of good gut function in later growth stages.
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