Cattle are frequently infected with salmonellae by fecaloral transmission or by being fed contaminated animal protein byproducts (40% are reported contaminated in the U.S.). Bothcould propagate salmonellosis in feedlots. Research indicates that stress can induce shedding of salmonellae by asymptomatic carriers. Stress factors associated withsalmonellosis include: transportation, starvation, changes in ration, overcrowding, age, pregnancy, parturition, exertion, anesthesia, surgery, intercurrentdisease, and oral treatment withantibioticsand anthelmintics. In this study, we have attempted to correlate dosage of S. typhimurium inoculumwithdisease, persistence of infection, and environmental contamination. The persistence and spread of S. newport placed on the skin of cattle was also studied
