Project Number: 6202-32000-030-61
Project Type: Reimbursable

Start Date: Oct 01, 2012
End Date: May 31, 2014

Objective:
Investigate the potential explanations for the seasonal and regional differences in lymph node prevalence of Salmonella in feedlot cattle and elucidate the factors responsible for the differences observed in lymph node prevalence of Salmonella between fed beef and dairy cattle within the Southwest United States.

Approach:
Seasonal/Regional Feedlot Collections: Using a soil temperature map, we will identify feedlots within 3 or 4 of the ground temperature zones (TX, OK, or KS, and NE) and sample two feedlots/zones during the winter and spring months (Jan, Mar, May). Numerous samples/observations will be collected on each feedlot visit, including: pen fecal pats (4 pens/feedlot; representing 30% of cattle within each pen), hide swabs, feed and water samples, pen soil samples and soil temperature, flies and other insects, fly burden, ambient temperature, humidity, and precipitation. Samples will be cultured for Salmonella and isolates serogrouped. Dairy versus Feedlot Collections: Two feedlots and four dairies (two vaccinated for Salmonella and two non-vaccinated herds), all located within a 100-mile radius in the Southwestern United States, will be utilized in the proposed research. All dairies and feedlots will be sampled monthly (Jan, Mar, May) during the same week. Numerous samples/observations will be collected at each location on each visit including: pen fecal pats (4 pens/operation; representing 30% of cattle within each pen), hide swabs, feed and water samples, pen soil samples and soil temperature, flies and other insects, fly burden, ambient temperature, humidity, and precipitation. Samples will be cultured for Salmonella and isolates serogrouped.