Long-Haul Transport and Lack of Preconditioning Increases Fecal Shedding of Escherichia coli and Escherichia coli O157:H7 by Calves

Abstract

The effects of weaning and transport on fecal shedding of Escherichia coli and on E. coli O157:H7 were investigated using 80 Angus and 94 Charolais range steer calves blocked by breed and assigned to four treatments. The calves were or were not preconditioned before transport on commercial cattle liner to the feedlot via long (15 h) or short (3 h) hauling duration, yielding preconditioned long haul (P-L; n = 44), preconditioned short haul (P-S; n = 44), nonpreconditioned long haul (NP-L; n = 43), and nonpreconditioned short haul (NP-S; n = 43). Preconditioned calves were vaccinated and weaned 29 and 13 days, respectively, before transport. Nonpreconditioned calves were weaned 1 day before long or short hauling, penned for 24 h and hauled again for 2 h, and vaccinated on arrival at the feedlot. Fecal samples were collected from calves while on pasture, at weaning, at loading for transport, on arrival at the feedlot, twice in the first week, and on days 7, 14, 21, and 28 for enumeration of total E. coli (biotype 1) and detection of E. coli O157:H7. No calves were positive for E. coli O157:H7 before transport. Following transport, more (P < 0.005) NP-L calves (6 of 43) tested positive for E. coli O157:H7 than did P-L (1 of 44), NP-S (1 of 43), or P-S (0 of 44) calves, and on days 0, 1, 7, and 21, their levels of shedding of E. coli were higher (P < 0.005). The calves' susceptibility to infection from the environment (possibly the holding facilities or feedlot pens) was likely elevated by the stresses of weaning, transport, and relocation. Lack of preconditioning and long periods of transport (NP-L) increased fecal shedding of E. coli and E. coli O157:H7. Preconditioning may serve to reduce E. coli O157:H7 shedding by range calves on arrival at the feedlot.

Effect of Subtherapeutic Administration of Antibiotics on the Prevalence of Antibiotic-Resistant Escherichia coli Bacteria in Feedlot Cattle

“…We have previously observed that a rifampinresistant isolate introduced (via oral inoculation) into a subset of cattle in a feedlot pen was acquired and shed in the feces of all animals in the pen within 48 h of introduction (58). Transmission of this isolate between pens of cattle was observed only during the week immediately after the animals' entry to the feedlot, a period in which stress may have altered the stability of microbial populations within the digestive tract (3,9). Coincidently, the increase in shedding on day 113 occurred during the beginning of the transition phase to the grain-based diet, a period of ecological shift in the makeup of the microbial populations within the digestive tract.…”

Inactivation of Enterohemorrhagic Escherichia coli in Rumen Content- or Feces-Contaminated Drinking Water for Cattle

“…Cattle are a major reservoir of E. coli O157:H7 (2, 4, 5, 7), and cattle water troughs are important sources of the pathogen on farms (2,4,5,7,17,20,21,27,28,37). Studies have further revealed that when present in cattle drinking water, the pathogen was disseminated to other cattle consuming the contaminated water (19,29).…”

Prácticas de bioseguridad adoptadas en grandes explotaciones de bovinos de carne de la zona Central de Chile

“…Esta medida es relevante, ya que los animales durante el transporte podrían incrementar la diseminación de agentes como E coli O157 y Salmonella spp., los cuales tienen la capacidad de sobrevivir por periodos prolongados en este ambiente (Brandt et al 2008;Bach et al 2004). Existe un grado aceptable de la mayoría de las medidas evaluadas, a excepción de la existencia de un proceso de desinfección, sin embargo esta deficiencia se compensa con la existencia de acceso restringido y estacionamientos en la periferia, lo que disminuiría el riesgo de ingreso de agentes patógenos.…”