Prevalence of Salmonella and Campylobacter in beef cattle from transport to slaughter.

The objective of this study was to evaluate the effect of typical production practices during the transport of cattle on the resulting incidence of Salmonella and Campylobacter in the feces, on the hides, and on the carcasses of these cattle and in the environment (trucks, holding pens, and knock boxes). Various factors were evaluated, including the type of animal (feedlot cattle vs. adult pasture cattle), the breed of cattle, the body condition of the animal, the age of the animal, the time of feed and water withdrawal, the contamination level of the transport vehicle at the feedlot or farm, the transport time, the time cattle were held in the holding pen at the plant, and the contamination level of the holding pen. Four groups of each type of animal were sampled on different days. Samples were collected from cattle prior to transport and after transport (rectal and hide swabs) as well as from the carcasses of these cattle. Pre- and posttransit samples were also taken from the transport vehicle and from the holding pen and knock box at the slaughter facility. For feedlot cattle, fecal shedding stayed fairly constant for both organisms before and after transport (3 to 5% for Salmonella and 64 to 68% for Campylobacter). However, the shedding rate for adult cattle increased from 1 to 21% for Salmonella but stayed constant for Campylobacter (6 to 7%). Contamination of hides with Salmonella increased for both animal types from a level of 18 to 20% to a level 50 to 56%. For Campylobacter, the contamination level decreased from 25 to 13% for feedlot cattle but remained unchanged for adult animals (1 to 2%). Nineteen percent of feedlot cattle carcasses and 54% of adult cattle carcasses tested positive for Salmonella, while only2% of feedlot cattle carcasses and none of the adult cattle carcasses tested positive for Campylobacter. Thus, for feedlot cattle, the factors considered in this study did not affect the shedding of either organism but did affect the contamination of hides with both. For adult animals, the factors increased both shedding of and hide contamination with Salmonella only, not Campylobacter.