Introduction

When it comes to implementing coccidiosis control programs, nothing beats the hands-on experience of working with birds and seeing the performance results of different programs. Unfortunately, there is no ‘one size fits all’ solution for coccidiosis control in broilers, so programs need to be tailored to individual farms and flocks. Success with a particular program on one farm does not mean it will be successful on another farm.

Considerations

Before implementing any plan, the first consideration must always be the market and customer requirements regarding antibiotic usage. If birds are being grown under a ‘no antibiotics ever’ (NAE) system, this may also restrict the use of some ionophore products.

Once customer requirements are met, a balance must be struck between bird health and cost. This overlap can be most clearly seen in livability, feed conversion rate (FCR) and average daily gain (ADG). Consideration must also be given to the end weight of the birds with adjustments made to the coccidiosis control program for smaller vs larger birds where logistics allow.

Program types

There are various programs for controlling coccidiosis in poultry units, including:

1. Straight program
2. Shuttle program
3. Bioshuttle program
4. Vaccine only program

A straight program uses one product in the feed from start to finish whereas a shuttle program uses more than one product in the feed.

A bio-shuttle program combines a vaccine with a product in the feed. And finally, there is the vaccine only approach. Producers typically use a rotation of products over the course of a year to prevent resistance build-up.

Bioshuttle programs

Figure 1 shows the standard curve of oocysts per gram in broiler fecal samples over time following vaccination on day one. The vaccine should keep the oocyst count low in the first two weeks, and then an anticoccidial product in the feed will control oocyst counts in the later stages.

Combining a vaccine administered after hatch with an in-feed coccidiosis control product will have varying success depending on numerous factors. As a minimum, the anticoccidial product must efficiently control the cycling of the cocci, otherwise intestinal damage will occur, potentially leading to gangrenous dermatitis or other conditions.

Dermatitis is a complex, multi-factorial bacterial disease commonly associated with Clostridium species. It is mostly found in market-weight, healthy birds making it a very costly disease since the affected birds are fully fed. Death is rapid and followed by rapid decomposition of the carcass, so it is vital that birds are removed from the house quickly before pathogens are allowed to spread.

As dermatitis is very difficult, if not impossible to replicate in a trial situation, the links between coccidiosis and dermatitis are not fully known. One theory is that leaky gut caused by coccidiosis allows bacteria to pass through the gut wall and infect the bird. Another theory is that ionophores themselves contribute to dermatitis.

Shuttle program

Figure 2 illustrates a typical shuttle program.

If a shuttle program is not successful, it can lead to necrotic enteritis. Necrotic enteritis occurs when the clostridia in the gut produce a toxin which breaks down the gut barrier.

Vaccine only programs

In a vaccine only program, birds are vaccinated after hatch and cocci is allowed to cycle in the flock. But instead of introducing an anticoccidial product in the feed in the later stages as with a bioshuttle program, the birds are allowed to build up their own immunity.

Vaccine application is critical to the success of the program. Spray cabinets are used to ensure an even spread of the vaccine mix (other vaccines such as respiratory vaccines may be administered at the same time) over all the birds in the crate. Once applied, the chicks are exposed to a period of bright light (Figure 3) which stimulates preening and ingestion of the vaccine.

Another critical control point is turn-out time. Turning the birds out in only half of the house to start with ensures stocking density is high. This temporary limiting of space ensures the fecal shedding and ingestion cycle can take place. For USA integrator, the ideal turn out window is 8-10 days. If turnout occurs sooner than this, problems with necrotic enteritis have been seen.

Posting sessions

In the USA, posting sessions are used for several reasons, including evaluating the efficacy of coccidiosis control programs. A gut health posting session usually examines birds at various ages to give a good cross section of growth stages. It is important to sample live birds and only euthanize them immediately before observations are made to preserve the integrity of the gut. During the posting session, various sections of the gut are opened and examined for lesions visually and microscopically, by taking scrapings of the gut lining. Results from different posting sessions can be compared to look for improvement trends or areas for further consideration.

Troubleshooting

Sometimes things don’t always go according to plan. In some cases, there may be excessive cycling of coccidiosis which needs to be treated. This can be done using Amprolium in the drinking water, or alternatively, phytogenic products can be used. If necrotic enteritis is becoming a problem, it can be prevented using a vaccine (now available in the USA) or by using feed antibiotics (where permitted for use).

Conclusion

There are many coccidiosis control products available on the market now, giving producers plenty of flexibility and choice as to which program they apply in their flocks. Trying different programs and using data analysis to monitor the performance of the program will highlight the best option for each producer. USA integrator is currently using a vaccine-only program supported by an in-feed phytogenic product. Not only is this program successfully controlling coccidiosis, but it is also allowing chemical and ionophore products to be rested which will maximize their efficacy should they be needed in the future.