Clockwatchers: Cagle’s says the time is up for cocccidiosis and gangrenous dermatitis
“Those birds live 840 hours, which leaves us very little room for error or setbacks of any kind,” says Brad Harp, vice president for live operations. “It’s sort of like drag racing. If you miss second gear, you’ve already lost the race.”
Live-operations manager Rick Tullos agrees. “On birds that size, if you lose 8 hours of growth to disease or stress, that’s like 1% of the bird’s life. At that point, it’s all over but the crying.”
Producing seven to eight cycles of lighter-weight birds requires intensive management involving many variables — some predictable, some not. But for the production team at Cagle’s, maintaining good intestinal and respiratory health is key to the livability and performance of its birds.
‘Gut with a pair of lungs’
“It might sound a little crude, but to me, a chicken is basically a gut with a pair of lungs,” Harp says. “If we can keep both of those things healthy, feed our birds good nutrition and put them in the right environment, the rest is like falling off a log.”
Harp says respiratory diseases haven’t been a big issue in recent years. “But it wasn’t until recently that we realized how many problems we were having with intestinal health,” he concedes.“And they’ve been costly, too.”
Stopping the leak
Cagle’s had changed to its normal summer program in 2008, when it experienced a widespread and severe outbreak of gangrenous dermatitis. “We had 93% livability,” Tullos says. “Or, put another way, we were losing 7% before we could get them to market. That wasn’t acceptable.”
Gangrenous dermatitis is a costly disease that causes necrosis of the skin over the wings, thighs, breast and head in growing birds. It’s not an intestinal disease, per se, but outbreaks of the disease have been linked to resilient coccidia left uncontrolled by ionophore anticoccidials.
The evidence is circumstantial, but a growing number of producers have observed that birds vaccinated with Coccivac-B don’t develop gangrenous dermatitis. The vaccine itself doesn’t prevent the infection, but it is known that vaccinated birds don’t experience the late subclinical coccidiosis that can sometimes occur with feed medications.
To help stop dermatitis in its tracks, Harp and Tullos devised a two-pronged plan of attack designed to prevent coccidiosis leakage associated with the dermatitis.
First, they switched all broilers that were already in the field to a chemical anticoccidial at 18 days to shut down the coccidia organisms that weren’t controlled by the ionophore used in the starter feed. At the same time, they started vaccinating all day-old chicks entering the system with Coccivac-B.
“For us, it was like flipping on a light switch,” Tullos says. “We started flocks on Coccivac-B and the dermatitis went away — gone! — and our livability increased from 93% to 97%. Improvements like that usually don’t happen that fast in live production. Normally, it takes time for change to have an effect, but this was almost instant.”
‘Couldn’t keep the litter dry’
With dermatitis behind them and fall approaching, Harp and Tullos decided to stop vaccinating after two cycles. The plan was to switch to a new ionophore for one cycle and then rotate to nicarbazin in the starter and grower feeds for the winter program. But they never got that far. After 4 weeks on the ionophore, their birds started showing signs of coccidosis.
And it got worse, quickly.
By December they experienced a coccidiosis outbreak in birds that were just days from being processed. Livability plunged to as low as 75% on one farm.
“Cocci was bleeding through the ionophore program pretty badly. We just couldn’t keep the litter dry. It was like soup,” Harp says. “It was so severe, we considered euthanizing birds in two houses. Fortunately, switching to the chemical nicarbazin shut it down right away.”
Better health, uniformity
The following spring, Cagle’s started vaccinating all birds with Coccivac-B to improve coccidiosis control — and this time it vaccinated for five cycles. Better health wasn’t the only advantage to vaccinating birds. Harp and Tullos also noted that the vaccinated birds grew more uniformly. “They looked like widgets punched out of a factory press,” Tullos says. “It was amazing.”
Their contract growers noted the improved health and uniformity as well. When Cagle’s eventually went back to using feed medications for coccidiosis control, producers protested and said they “wanted more of those pink birds,” Tullos says, referring to the sprayed-on vaccine’s red dye. The dye, which eventually wears off, encourages early preening and distribution of the coccidial oocysts in the sprayed-on vaccine.
After using the vaccine for five cycles in 2009, Cagle’s switched back to using feed medications in the colder months — a period when its growers “tighten up on ventilation,” Tullos says, making it harder to keep the litter dry and increasing the challenge from coccidiosis.
“We don’t have our growers where we want them yet on ventilation for using Coccivac-B year-round, but that’s an option to consider for the future,” Tullos adds.
Cagle’s hasn’t used an ionophore for coccidiosis control since December 2008. “After a couple of years, we might consider them again, but Brad and I are pretty gunshy,” Tullos says. “On the other hand, we’ve been very happy with the vaccine.”
Not for big birds only
Harp and Tullos also dismissed early concerns about birds experiencing a momentary setback following vaccination and not being able to make up the loss before processing.
“We initially lost some ground in feed conversion, but we were told that would happen and it was only in the first round,” Tullos says. “But you’ll gain it back over the cycles that you stay on Coccivac-B.”
For example, birds on the first round of Coccivac-B had a feed-conversion rate of 1.78 pound per pound of gain. By the third round, feed conversion improved to 1.72.
More importantly, they say, vaccinated birds had lower mortality than medicated birds and also grew more uniformly, which makes them easier to process.
“All those concerns in the past about using Coccivac-B in small birds, they don’t bother me anymore,” Harp says. "And another thing — there's no [feed medication] withdrawal time to cause concern," which provides more processing flexibility.
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