Coccidiosis has long been a significant disease facing pullet rearers, with outbreaks significantly impacting economic production.

Proactively preventing the disease via vaccinations is commonplace among pullet rearers, but success can be down to several factors.

Here, Andy Payne, key account manager for poultry at MSD Animal Health UK, discusses how to control coccidiosis in poultry flocks. 

MSD markets coccidiosis vaccines under the Paracox brand in the UK.

As vaccination success can depend on several components, Mr Payne also gives his top tips for effective application and uptake of vaccines to develop early immunity.

Controlling coccidiosis in poultry flocks 

“In layer flocks, vaccines are designed to induce immunity safely and as quickly as possible when administered properly,” Mr Payne explains.

MSD’s Andy Payne

“The way that a coccidiosis vaccine works is that live sporulated oocysts must be ingested to establish low levels of infection and induce immunity. 

“But, because the strains used in a vaccine have shortened life cycles compared to field strains, fewer reproductive cycles occur before the oocysts are excreted by the bird, hence little damage is caused to the intestinal tissue.  

“As the birds become immune, the level of oocyst shedding is reduced, and the site is seeded with these attenuated vaccinal strains which do not cause harm to the birds,” he adds. 

Challenges for effective coccidiosis vaccinations 

When it comes to effective vaccination, Mr Payne explains that one of the key objectives is making sure all birds receive a full dose. 

If this is not achieved, the flock will still eventually develop immunity, but it will take longer for all birds to complete the required cycles and therefore be capable of fighting off the disease. 

This can significantly impact bird weight and uniformity.

“Mixing a coccidiosis vaccine with a tenacious solvent as opposed to water, can increase uptake in birds. 

“The high viscosity liquid clings to feathers longer which enhances preening and therefore vaccine uptake.” 

Top tips when using coccidiosis vaccines on-farm 

Ensuring vaccines are stored and administered correctly can significantly affect their efficacy, so there are a few essential things to remember before starting:

  • Prepare in advance – Once you’ve selected the vaccine you wish to use, make sure you order it in plenty of time before the chicks arrive. This means that you’ll be able to administer the vaccine as soon as the chicks hatch.  
  • Storage – Making sure your vaccine is stored at the correct fridge temperature is vital. Otherwise, you run the risk of the vaccine becoming ineffective. Place a thermometer inside the fridge to keep an accurate record and look at the product data-sheet to verify temperature requirements. 
  • Shake the vaccine bag well before use –This will ensure the oocysts remain within the suspension. 
  • Sprayer calibration – Some vaccines can be applied to chicks via a sprayer. This is usually done while the chicks are still in their baskets on arrival. Ensure the sprayer is calibrated, and you have calculated how many seconds you need to spray each basket for to achieve even coverage. 
  • Using a dye or coloured solvent –The addition of the colour means you can see where you have been and ensure even coverage.
  • Lighting – With spray-on vaccines, you rely on the chicks preening one another to ingest the vaccine. Therefore, keeping lighting bright up to 15 minutes after the application will mean they are more active and more likely to consume the vaccine.
  • Oocyst per gram (OPG) counts and specification – These are an excellent tool to monitor how well the vaccine is cycling within a flock. Your vet will be able to take the required faecal samples and interpret the results. 

What is coccidiosis?

Coccidiosis is a disease of the intestine caused by various species of a single cell gut parasite called an Eimeria.  

The Eimeria life cycle begins as oocysts, which the bird ingests from the litter.  

The parasite’s life cycle is complex and characterised by parasite multiplication in the cells lining the intestines, and it is at this stage that damage occurs.

Infected birds excrete fresh oocysts into the environment days before any symptoms become apparent, enabling the disease to spread quickly throughout a flock. 

Clinical signs of coccidiosis are mainly defined by the causative Eimeria species and can include blood in the faeces, weight loss and visibly sick birds.