Disease challenges of cage-free egg production
Disease and emerging pathogens present cage-free egg producers with challenges that may require changes in operational practices.
A survey of the Association of Veterinarians in Egg Production presented at the United States Animal Health Association annual meeting in October 2017 by Dr. Eric Gingerich, technical services specialist of poultry with Diamond V, gave interesting insights into the issues facing producers of cage-free eggs. Coccidiosis and related diseases, piling, cannibalism, E. coli, vaccinal infectious laryngotracheitis (ILT), Mycoplasma gallisepticum and roundworms were identified as the most important challenges in pullets and layers. In addition, other emerging or re-appearing conditions warrant monitoring.
Various diseases and control tactics
Veterinarians ranked coccidiosis as the most challenging disease in cage-free pullet production. Gingerich estimates that 95 percent or more layer pullets are given a coccidiosis vaccine, which requires good management practices to ensure success. The live oocyst vaccine needs to recycle two or three times through the bird to establish adequate immunity, so litter moisture and humidity management are important. Lack of adequate coccidiosis immunity allows secondary infections, most often necrotic enteritis, to develop. Both coccidiosis and necrotic enteritis result in increased mortality as well as reduced growth and egg production.
Read the entire report about disease challenges of cage-free egg production in the March issue of Egg Industry.
While more of a management than disease issue, piling was ranked second in the pullet survey as producers seek answers on how to prevent this phenomenon that causes significant mortality losses. There appears to be a strain relationship, as piling is commonly seen in brown birds and some strains of white pullets. Producers are learning that a uniform environment may reduce the incidence, so they are working to keep light intensity, temperature and litter depth consistent across the pullet house.
Increased reactions to live respiratory vaccines are observed when E. coli infections are present in growing pullets. After moving to the lay house, E. coli may contribute to significantly higher mortalities of 0.5 to 4 percent per week, as a secondary invader after respiratory issues may develop from high ammonia levels or disease challenges from mycoplasmas or infectious bronchitis. When water lines are contaminated with E. coli, this bacterium can be a primary pathogen. A live vaccine is used during pullet grow-out as a preventative and has also been used with success as a treatment during an outbreak.