SUMMER HELP

Goldkist veterinarian focuses on coccidiosis vaccination to give ionophores and other drugs a much needed rest.

It used to be that resting anticoccidials with rotation or shuttle programs was the only way to improve their efficacy and performance in the field. But with resistance on the increase and no new in-feed anticoccidials on the horizon, poultry companies are beginning to rethink their long-term strategy for managing this disease.

For many operations, vaccinating "not medicating "for coccidiosis is not only filling the void, but also breathing new life into in-feed products that were last seen heading for the obituary column. While in Atlanta for the International Poultry Congress, CocciForum flagged down key decision-makers at leading US poultry companies for their thoughts on this issue. Following is the first in a series of post-convention reports.

Roney: 'Any time you're not using a drug, you're resting it.'

Dr. Steve Roney, director of veterinary services at Goldkist, Inc., Atlanta, reports using coccidiosis vaccine mostly in the summer months and says it's a big help keeping resistant strains down in the house.

"Vaccination during the summer helps us lengthen the time that we can use our ionophores and chemicals," he explains. "In other words, we're placing the vaccine in at a strategic time so that we can get better control at other times when we have heavier cocci challenge from weather "times when we're using ionophores and chemicals for cocci control."

The main aim for Goldkist in implementing use of the vaccine, says Roney, was to regain the sensitivities of cocci organisms to the ionophores and other drugs they were using. And, he says, that's pretty much the way things have worked out.

"Over time, in our experimenting with the vaccine and also talking with other people who've used it, we think that is the way it's going to be increasingly used in the future "to use it in rotation throughout the year, or one time during the year, to break up the resistant cycles from the coccidiosis," he says.

Backed by science

The strategy Roney's been employing at Goldkist is backed by solid science. For example, researchers at the University of Arkansas recently wrapped up a long-term study that compared how several different rotation programs affected strains of salinomycin-resistant coccidia.

In one group, complete rest from anticoccidials for four consecutive flocks resulted in improved, but not restored, sensitivity to salinomycin. In another group that received three different shuttles of Clinacox - Clinacox/salinomycin, salinomycin/ Clinacox, or Clinacox/Clinacox "there was nearly complete restoration of sensitivity to salinomycin.

Interestingly, in still another group, when Clinacox was used alone for four consecutive flocks, the result was, again, nearly complete restoration of sensitivty to salinomycin.

Resting drugs

Roney feels this concept of "resting" drugs is becoming increasingly integral to the success of many modern poultry operations.

"Any time you're not using a drug, you're resting it," he reasons. "So you're hoping that when you come back to that drug you're going to get increased efficacy."

The veterinarian thinks there's one other plus to including a vaccine in the program.

"With long withdrawal times on conventional cocci programs, we get the challenge of the oocysts pushed farther in the bird's life, to the point where we can't control it with chemicals or with ionophores," he says. "When that's the case, we can come in with the cocci vaccine and it'll push the challenge back earlier in the bird's life, making it easier for our standard programs to work when we go back to them."

Roney is encouraged by results he's seen so far with Coccivac.

"Based on what I've experienced in the past couple of years, I think we're on the right track. We're not all the way there yet. But with the limited amount of drugs that we have available, and seeing no new products on the horizon, I'm convinced that vaccination is going to be a huge part of our program in the future," he predicts.

Source: CocciForum Issue No.8, Schering-Plough Animal Health.