Behavior of cattle towards devices to detect food-safety pathogens in feedlot pens

Abstract

Our objective was to optimize a protocol using rope devices designed to detect Escherichia coli O157:H7 in feedlot pens by (1) determining if the number of devices influenced the percent of cattle sampled, (2) describing when the cattle contacted the devices, and (3) determining if the time of removal or number of devices influenced the recovery or E. coli O157:H7. Overall, 2948 cattle were observed in 24 commercial feedlot pens, eight pens each in the autumn, winter and summer. Three or seven devices per pen were placed near the water tank and over the feed bunk approximately one hour prior to sunset. Cattle were observed for a 2-hour period to measure (1) the duration of time until they made contact with the devices, and (2) the type of contact they had with the devices. One tail from each of the devices was collected at the end of the 2-hour observation period (ending approximately one hour after sundown) and the other tail was collected the next morning to test for the presence of E. coli O157:H7. Recovery of E. coli O157:H7 was not significantly different using three or seven devices (p>0.10), or if devices were left available overnight (p>0.10). The rate of first contacts did not differ between pens with three or seven devices in any of the 30-minute periods of observation (p>0.50). However, regardless of the number of devices in the pen, the first contact rate was highest in the first 30 minutes and decreased significantly with time (p<0.001). Over the 2-hour observation period, a greater percentage of cattle in pens with seven devices had physical (p<0.01), brief oral (p<0.02), or prolonged oral contact (p<0.01) than cattle in pens with three devices. Therefore, to maximize the number of cattle sampled per pen, the number of devices and length of time the devices are available were important factors of the sampling strategy.