Retrospective Assessment of Vaccination in Broiler Turkeys Under Field Conditions in 37 Farms from Brittany (France).

Colibacillosis is a common bacterial disease in broiler production worldwide. It is emerging as a serious health concern in turkey production. Until recently, the disease was managed through antimicrobial therapy. However, such preventive strategies are no longer considered sustainable, and the advent of a live commercial vaccine registered for turkeys has modified health management plans in turkey production systems. In a French farming cooperative representing 10% of the country's turkey production, the vaccine was prescribed in two categories of farms: those with recurrent colibacillosis where an O78 strain had been isolated, and those with sporadic outbreaks, where other serotypes had been documented. The commercial vaccine was administered in the first and third week of age. Performance data were collected retrospectively for all flocks produced over a 4-yr period from 37 turkey farm members of the cooperative. Segregated flocks from recurrent or sporadic farms, and whether or not vaccination had been performed, were analyzed and recorded. In farms with sporadic colibacillosis, vaccination significantly improved mortality rate and all performance parameters (average condemnation rate at the slaughterhouse, average feed conversion ratio, average weight per slaughtered turkey in each flock, average economic margin per flock, and performance index). Farms with recurrent outbreaks had comparable results, except for average flock mortality and condemnation rates, which were numerically reduced in vaccinated flocks compared to flocks that had not been vaccinated. This retrospective study contributes to the weight of evidence in favor of colibacillosis control through vaccination in turkey production.