Coccidiosis Vaccination is put to the Test
Vaccination, he thought, might be a good fit with the poultry company’s plan to decrease its use of antibiotics, including in-feed anticoccidials.

The growing emphasis on food safety and new regulations aimed at preventing cross-contamination of poultry feed with unintended drugs underscored the importance of exploring new disease-management strategies. Ets Michel’s general manager, Ludovic Michel, also felt the new regulations were making anticoccidials too complicated to manage at the feed mill.

In addition, Ets Michel was concerned about subclinical coccidiosis, which quietly erodes performance and profits. “Visually, we saw nothing — only some abnormal droppings and a bit higher feed-conversion ratio,” Coeudevez says.

Vaccine Trials

Ets Michel, headquartered in St Germain En Cogles, France, annually processes 3 million Certi’ Ferme broilers — birds with an enhanced quality certification intended to set them apart from competitors — as well as 20 million standard broilers. Switching from in-feed anticoccidials to vaccination would, therefore, be a big change. However, Coeudevez first wanted evidence that it would work and decided a trial was in order.

During the last half of 2008, Ets Michel initiated the use of Paracox-5, a live, attenuated coccidiosis vaccine, in all of the company’s 65 certified broiler flocks, amounting to 1.4 million birds. Three flocks per house were spray-vaccinated at the hatchery on day 1 of age.

“We tried the vaccine for 6 months during two seasons and in several consecutive flocks to relieve any possible doubts we had about the vaccine’s efficacy,” Coeudevez says.

Jean-Luc Dupont, then with Intervet/Schering-Plough Animal Health, the manufacturer of Paracox-5, managed the trial. This included teaching Ets Michel’s staff how to properly manage vaccinated flocks and take litter samples, which were sent to the Bio Chêne Vert laboratory, where oocyst-per-gram counts were done. Samples were sent at 7, 14, 21, 28, 35 and 42 days after each vaccination cycle.

Better FCR, More Uniformity

The results were good, with improvement in all vaccinated flocks, Coeudevez says. “We saw a real decrease in coccidial pressure on farms, with a better feed-conversion ratio (FCR) and more homogenous flocks,” even on farms with high coccidial pressure (see Table 1).

Improved uniformity was especially advantageous because most of the certified broilers are sold as a group at a fixed weight, he notes.

The trial results were convincing, Coeudevez continues. In certified broilers, there were no other deviations in management besides vaccination, nor did the feed formulas, the type of birds or farmers change, so the improvement in FCR can’t be attributed to anything else.

The results were impressive enough that all certified broilers are now spray-vaccinated against coccidiosis at the hatcheries, and Ets Michel is reaping the benefits of having flocks without subclinical coccidiosis, he says.

The company now plans to expand coccidiosis vaccination to its standard broiler operation at the end of 2010.

Stimulates Early Immunity

Dr. Alain Riggi, a technical service veterinarian with Intervet/Schering-Plough Animal Health, says that about 80% of coccidiosis cases are subclinical. Dr. Juliene Flori, of Chêne-Vert Conseil, adds that upon necropsy, birds with subclinical coccidiosis have lesion scores of only 1 or 2, but “economically, it’s a very expensive disease…It’s a very insidious disease.”

Riggi explains that in unvaccinated flocks or in medicated birds that leak infectious coccidial oocysts when their sensitivity to anticoccidials declines, coccidial pressure tends to occur late into the production cycle. This can be costly and it can do serious damage to the FCR because it’s the same time that birds eat and grow the most.

Vaccination reverses the process. Birds are exposed to and develop immunity against coccidiosis early in life and are protected against a coccidial challenge for the rest of their lives, he says.

The veterinarian cautions that it takes a few cycles of vaccination for coccidial oocysts in the vaccine to replace wild coccidial strains in the poultry house and to achieve the best results with coccidiosis vaccination, as demonstrated by the Ets Michel experience.

A cost analysis conducted by Nicolas Serin, then an agricultural student training at Intervet/Schering-Plough Animal Health, demonstrated that the cost of in-feed anticoccidials, even with additional efforts at the feed mill to prevent feed contamination and poultry meat residues, still appears less expensive than coccidiosis vaccination. However, when the impact on performance is factored in, such as the lower weight gain and higher FCR that subclinical coccidiosis causes, it is more profitable to vaccinate. Perhaps more importantly, vaccination simplifies management at the feed mill and relieves concerns about contamination and residues.

“If we take into account the technical gains enabled by vaccination, we earn money,” Coeudevez says. “And, we have to consider peace of mind, which can’t be calculated.”

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