Optimising Broiler Performance: Progressive Improvement during Multiple Flock Cycles of CoccivacB Vaccination with Enradin

US - Intestinal health for optimum broiler performance requires both the control of coccidiosis and the proper balance of bacterial microflora. The imbalance of microflora often begins as a consequence of intestinal irritation. The initial irritant, often coccidiosis, causes cell damage and the production of excess mucous in response to the cytokines produced as part of the intestinal immune response.
calendar icon 7 December 2012
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The cellular debris and mucous become a nutrient source for undesirable intestinal microflora, such as Clostridium perfringens.

The clostridia continue the cycle of intestinal damage and mucous production by releasing powerful toxins, resulting in wet feces from excessive mucous production, or in the worst case, causing necrotic enteritis.

While clinical coccidiosis outbreaks are easily controlled with vaccination, effective subclinical coccidiosis control for maximum performance requires multiple vaccinated flock grow-out cycles.

In the initial vaccinated flock, wild strain Eimeria challenge is often severe, despite farm cleanout and disinfection.

With each successive vaccinated flock, the challenge becomes less severe until the vaccine becomes the dominant Eimeria population in the poultry house. Flock performance progressively improves over two to four flock cycles of coccidiosis vaccination.

This study was designed to improve intestinal health in two ways: improved coccidiosis control through vaccination with Coccivac®-B and improved Clostridium perfringens control with Enradin®.

Flocks were compared to two previous flock cycles using ionophore anticoccidials with generic feed antibiotics, and to concurrent coccidiosis vaccinated flock cycles using BMD® (bacitracin methylene disalicylate) as a comparison to Enradin.

Study Design

One hundred twenty thousand broilers were divided into Groups A, B, C and D in two environmentally controlled, double-deck commercial broiler houses located in Taiwan. The study was conducted over six successive flock grow-out cycles. Basic feed formulation was the same, except for medication changes indicated.


  • Late subclinical coccidiosis is detrimental to performance. But changing the timing and level of coccidiosis insult on a farm with vaccination takes some time.
  • In this multi-flock study, broiler performance improved with each successive flock vaccinated with Coccivac-B.
  • Each successive vaccinated flock improved even more when Enradin was used vs BMD.
  • The Performance Index stabilized at > 370 with Coccivac-B + Enradin after three consecutive flock cycles (bird age 34.5 days, weight 2.0 kg, FCR 1.55).
  • Despite higher program cost, net profit improved with each successive flock that used Coccivac-B + Enradin, rising US$0.071/kg vs the best ionophore flock in the trial.

Further Reading

You can view the full report by clicking here.

Find out more information on coccidiosis by clicking here.

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