Effect of seasons in shedding pattern of Salmonella in layer poultry birds

The current investigation was an attempt to study the shedding pattern of Salmonella in laying chicken to explore seasonal variation in the dynamics of Salmonella containing eggs. A total of 1800 samples specifically as fecal samples and eggs were collected from selected 50 layer birds at different time intervals during different seasons of year 2007. The prevalence of Salmonella in feces, egg shell and egg yolk contents was assessed and correlated the shedding pattern with environmental variables i.e., temperature and relative humidity Prevalence of Salmonella was highest during July to August and lowest during January and December in the year 2007. A stronger positive correlation was observed between ambient temperature and Salmonella shedding in feces (r= 0.57) than relative humidity (r= 0.35). Significant correlation was also observed between ambient temperature and Salmonella shedding in egg shell (r= 0.53, P<0.01) and egg yolk (r= 0.39, P<0.05). Further, presence of Salmonella in the fecal samples of layer birds was well correlated with their presence in egg shell (r= 0.98) as well as in egg yolk (r= 0.88). It may be concluded that faecal shedding of Salmonella was higher during summer suggesting the accelerating role of ambient temperature for the pathogen.