Chemotherapeutic intervention and excellent flock management impact successful coccidiosis control
While anticoccidial compounds are usually credited when coccidia control efforts are successful, flock management is an equally important component of optimal bird health. Birds that are stressed and in poor health have compromised immune systems incapable of adequately responding to antigens. A functional, responsive immune system is critical for successful coccidia control.
Numerous management factors can significantly→
affect the success of coccidia control efforts. Poultry managers must strive to provide an environment where anticoccidials can perform most effectively. A discussion of key areas for vigilant coccidia oversight follows.
Management factors can significantly affect the success of coccidia control efforts, so poultry managers must provide an environment where anticoccidials can perform most effectively. Efforts must be directed towards maintaining and maximising feed consumption.
Feed quality and management
Birds require nutritious, high-quality feeds to maintain optimal consumption, growth, and health. High moisture feed, poor pelleting, off-grade ingredients, and mycotoxin contamination compromise formulations and caloric efficiency. Furthermore, feed must be formulated to contain the correct quantity of anticoccidial to allow for coccidiosis prevention.
Under dosing an anticoccidial can severely erode drug efficacy; overdosing may affect palatability and performance. Premature drug withdrawal schemes can also degrade control success.
Because anticoccidials are administered in the ration, feed consumption is a critical aspect of coccidiosis control. If feed consumption drops, drug intake proportionately falls, thus under dosing the bird and hampering drug efficacy. Effort must be directed toward maintaining and maximizing feed consumption. Quality feed ingredients, sufficient feeder space, low levels of stress, and many other management factors can influence feed intake and, therefore, the success of coccidiosis control measures.
Water and moisture
Diligent water management and moisture removal can directly affect coccidia challenge levels. Viability of coccidia in broiler houses is related to litter moisture. Wet, caked litter with high moisture levels enhances both coccidial and bacterial challenges. Thus, it is important that litter moisture be maintained at appropriate levels to prevent these elevated challenges. In addition, wet and caked litter should be promptly removed from production facilities and replaced with clean, dry material.
Water spillage from drinking systems that are poorly designed or in disrepair can contribute to wet litter. Enclosed drinking systems, both nipple and cup-type, can reduce litter moisture. However, water must be easily accessible to the birds. Any restriction in water consumption usually causes a corresponding drop in feed consumption which, as discussed earlier, can adversely impact bird health and anticoccidial intake.
Ventilation is a key component of moisture management, especially when the quantity of moisture in a broiler house is considered. A 20,000- bird flock will generate over 150,000 litres of water by 46 days of age, equivalent to 10 centimeters of rain in the broiler house. Therefore, adequate ventilation from one day of age to market age is required to successfully control litter moisture. Ventilation rates must be carefully coordinated with evaporative cooling systems so that relative humidity and litter moisture are adequately controlled. Factors such as geography, altitude, season, temperature, and age of the flock must all be considered in designing systems to regulate humidity and ventilation.
High numbers of chickens in a small area greatly increases the number of coccidia in the litter. Even exhaustive sanitation programs cannot overcome the increased coccidia challenge associated with increased bird densities. Maintenance of an appropriate stocking density in the broiler house will directly impact the coccidial challenge confronted by each bird.
The period of time between flocks in a broiler house can significantly affect the viability of coccidial oocysts in the litter. Downtimes of one week or less can contribute to coccidial challenges because most oocysts can remain viable for several days.
Many properly managed production operations use downtimes of two weeks, allowing the litter to dry out, which reduces challenges of both coccidial and microbial organisms.
Reducing stress plays an important role in a bird’s ability to cope with
disease challenges. Broilers are raised most efficiently when environmental temperatures match the bird’s needs at each stage of growth. Chilling of birds can reduce the ability of broilers to fight infections, while heat stress can also weaken the immune system. Both situations increase birds’ susceptibility to a variety of pathogens, including coccidia. High ambient temperatures may also depress feed consumption and anticoccidial intake, leading to decreased coccidial control.
Concurrent health programs must control other infectious agents such as bacteria, viruses, and fungi. Viral vaccination programs should emphasise infectious bursal disease and other immunosuppresive diseases, as well as the major respiratory viruses. Successful, comprehensive health programs help ensure that the immune system is responsive to coccidia exposure and, in alliance with the anticoccidial, able to limit the economic impact of coccidiosis. Respiratory diseases usually result in depression of feed and anticoccidial consumption, further illustrating the importance of controlling these diseases.
Good flow management is a prerequisite for optimal bird health, helping to maintain a functional, responsive immune system that is critical for successful coccidia control. Management factors that significantly impact the success of coccidiosis control programs include feed quality, moisture removal, bird density, downtime between flocks, temperature regulation, and concurrent health programs. These factors help ensure adequate drug content in the feed, encourage feed consumption, reduce coccidia populations in the litter, limit stress, and prevent complicating bacterial and viral infections. Quality management helps create and maintain an environment where anticoccidials can perform their job most effectively.¡