Preventive Practices
Environmental Management
Environmental factors that are of significance for the control of coccidiosis and poultry health include: stocking density, litter condition, temperature, feeding and water provision and ventilation. At temperatures causing discomfort, feed consumption decreases and thus so does consumption of the anticoccidial. Insufficient ventilation could lead to wet litter, which facilitates the sporulation of Eimeria. An increase in litter humidity by 15% – 35% is necessary for the sporulation of oocysts and is crucial after the application of coccidiosis vaccines to allow adequate sporulated oocysts to re-infect birds to establish a long lasting immunity. High population density poses an increased risk of coccidiosis due to the competition for food and water among the chickens, as well as a higher concentration of oocysts (Hamet et al. 1982). Insufficient feeding and drinking space due to overcrowding has an influence on feed consumption, and thus also over the intake of anticoccidials. The quality of the feed, i.e. adequate levels of protein, minerals, nutritional supplements and anticoccidials, is of considerable importance for the prevention of coccidiosis, especially in developing immunity in vaccinated birds.
In addition to the use anticoccidials and vaccinations, there are a number of other management practices that plays a role in coccidiosis management. Of particular importance are flock nutrition and biosecurity.
Feed & Nutrition
Different nutrients have been shown to have different effects on the prevalence of a coccidian infection in poultry flocks. Some examples from scientific literature are listed below:
For many years, anticoccidial drugs have been considered the gold standard for use as a preventative in feed medication, with most drugs either being classified as a coccidiostat or a coccidiocide.
- Coccidiostatic drugs arrest the development of the protozoa at specific stages of its lifecycle; withdrawal of the drug will allow the lifecycle to continue to completion.
- Coccidiocidal drugs kill or irreversibly damage the parasite at most lifecycle stages, with no sign of disease relapse following drug withdrawal.
Some drugs may have both coccidiostatic and coccidiocidal properties, depending on the dose used and the time the oocysts are exposed to the drug.
The biggest problem with anticoccidial products is the development of resistance.
Factors contributing to anticoccidial product resistance
- Higher reproductive potential of coccidia
- Long-term exposure to anticoccidial drugs
- Not using anticoccidials at the correct dosage
Managing this resistance is typically done using various types of programs
However, despite ongoing attempts to avoid drug resistance, it remains a leading limitation of anticoccidial programs. As well, consumers are becoming increasingly concerned about the use of drugs and/or chemicals as standard inclusions in feed for food-producing animals. Since research has repeatedly demonstrated that treating diseased birds is much less effective than preventing coccidiosis outbreaks in the first place, vaccination is a logical solution.
Resistance is defined by the World Health Organization (WHO) as "the ability of a parasite strain to survive and/or multiply despite the administration and absorption of a drug in doses equal to or higher than those usually recommended but within the limits of tolerance of the subject" (WHO, 1965). |
Anticoccidials
For many years, anticoccidial drugs have been considered the gold standard for use as a preventative in feed medication, with most drugs either being classified as a coccidiostat or a coccidiocide.
- Coccidiostatic drugs arrest the development of the protozoa at specific stages of its lifecycle; withdrawal of the drug will allow the lifecycle to continue to completion.
- Coccidiocidal drugs kill or irreversibly damage the parasite at most lifecycle stages, with no sign of disease relapse following drug withdrawal.
Some drugs may have both coccidiostatic and coccidiocidal properties, depending on the dose used and the time the oocysts are exposed to the drug.
The biggest problem with anticoccidial products is the development of resistance.
Factors contributing to anticoccidial product resistance
- Higher reproductive potential of coccidia
- Long-term exposure to anticoccidial drugs
- Not using anticoccidials at the correct dosage
Managing this resistance is typically done using various types of programs
However, despite ongoing attempts to avoid drug resistance, it remains a leading limitation of anticoccidial programs. As well, consumers are becoming increasingly concerned about the use of drugs and/or chemicals as standard inclusions in feed for food-producing animals. Since research has repeatedly demonstrated that treating diseased birds is much less effective than preventing coccidiosis outbreaks in the first place, vaccination is a logical solution.
Resistance is defined by the World Health Organization (WHO) as "the ability of a parasite strain to survive and/or multiply despite the administration and absorption of a drug in doses equal to or higher than those usually recommended but within the limits of tolerance of the subject" (WHO, 1965). |
Vaccination
Live oocyst vaccines against coccidiosis in poultry have been successfully used by the industry since 1965. To date, the vaccines have mostly been used by breeder flocks but, in recent years, have been more commonly used for commercial broilers, roasters and turkeys, particularly in the USA, Latin America and Europe.
Coccidiosis vaccines induce protective immunity, in various degrees, to protozoal infection through controlled re-infection during the first four to five weeks of a bird’s life. The complex lifecycle stimulates a number of immunological responses (innate, specific and non-specific) which vary in anticoccidial effect.
Precocious and Non-Precocious coccidiosis vaccines have been developed.