Age susceptibility and excretion of Salmonella typhimurium in calves

Abstract

SUMMARYTwo groups of calves were dosed orally with 104, 105, and 106S. typhimurium at approximately 2 days of age and at 14–21 days of age. No obvious clinical signs were observed with this strain, but younger calves excreted the salmonellas in the faeces for longer periods than older animals. The younger animals also excreted more salmonellas per gram of faeces in the first week following dosing. These observations may explain why salmonella cross-infection is likely to occur where very young calves are congregated. Following cessation of excretion of salmonellas in the faeces and subsequent slaughter of calves, examination of all the mesenteric, caecal, and colic lymph nodes showed these to be the most useful sites for recovery of salmonellas.Provided good nutrition and hygienic conditions prevail, calves retained on their farm of origin for longer periods are more likely to recover from neonatal salmonella infections.