Dr. Charles Broussard

To be vaccinated for coccidiosis or not to be vaccinated: For broilers raised to lighter weights, that is the question.

Why wouldn't producers want to vaccinate birds 4.2 lbs and less? One old school of thought suggests that vaccinating birds marketed at light weights against coccidiosis results in performance loss. That's because vaccination introduces live coccidial oocysts to the chickens - a process that produces a reaction and subsequent intestinal disruption.

With vaccinated birds managed in a 40- to 42-day or even shorter production cycle, decreased feed intake and weight gain setbacks could be intensified, and perhaps never overcome.

New Evidence

Fortunately, a new school is evolving to empower small bird producers with tools for vaccination program success. "We're learning that vaccination reactions are not as severe as industry once believed," says Dr. Charles Broussard, a technical service veterinarian with Schering-Plough Animal Health.

"There are now data to show that growth rate following vaccination is not as suppressed as originally anticipated, especially when optimum management procedures are in place and feed digestibility is increased." According to a recent study conducted by Southern Poultry Research, Inc. (SPR), Athens, Ga., the impact on overall performance is temporary and vaccinated birds do catch up or experience what nutritionists call "compensatory gain."

In the SPR study, the vaccine Coccivac-B was administered at hatching to a group of 960 chicks in a spray cabinet. Starting at day 1, another nonvaccinated group of 960 was fed salinomycin in starter and grower feeds, according to SPR president Dr. Greg Mathis. Commencing on day 14, individual weights and feed consumption were evaluated weekly for all birds in both groups.

At day 14, average feed conversion and live weights were similar in the vaccine and salinomycin groups, Mathis reports. By day 21, the vaccinated group trailed behind the nonvaccinated group. However, after 21 days, the vaccinated birds recovered and began to gain. About day 28, performance declined in birds receiving the anticoccidial due to the presence of subclinical coccidiosis. Under normal management conditions, this is a typical occurrence when this ionophore is used, Mathis notes.

"We found that the differences between treatments quickly diminish as the vaccinated birds recovered and the salinomycin birds were slightly affected," Mathis says. "By day 35, performance in both groups was essentially the same, and remained so throughout the remainder of the study."

Further information

Further information on SPAH's coccidiosis vaccines can be found on this website by Clicking Here

For more on Coccidiosis visit our on-line
Cocci-Forum is an on-line magazine dedicated to poultry health news and practical disease management.

Alternatively, click on one of the links below to download a free electronic copy of the magazine in PDF:

Issue No 4 Issue No 3 Issue No 2 Issue No 1