Dr. John McCarty, Senior Veterinarian, Merial, Inc. Dr. John McCarty has prepared a practical article dealing with control of coccidiosis in broiler growing with reference to winter conditions. Successful application of vaccines requires appropriate administration and structured monitoring as described. Coccidiosis can have an enormous impact on broiler performance which is most often reflected in reduced weight gain and decreased feed efficiency. It is considered to be the most costly pathogen challenge in modern broiler production in the U.S. While coccidiosis is a year-round problem, cold weather conditions can result in changes in the ecology in a broiler house that lead to increased cocci challenge. When the weather cools and the houses tighten up, disease challenge tends to increase in the chicken house. As ventilation is decreased to help conserve heat, more moisture remains in the house. The increased moisture, especially in the litter, favors increased bacterial, viral, and cocci load. Coccidia need moisture and heat for the oocysts to sporulate. Once these are sporulated, oocysts become infective to the chicken. The increase in moisture can lead to greater sporulation of the oocyst population. And, as more of the oocysts sporulate, birds are faced with a heavier cocci challenge. |