Location: Livestock Issues Research
Project Number: 3096-32000-008-020-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Aug 20, 2018
End Date: Aug 20, 2021
Objective:
The overall objective of this experiment is to determine if feeding NaturSafe to calves will reduce the acute phase response following an acute lipopolysaccharide challenge.
Approach:
Weaned beef calves (n = 32; 300-400 lbs; all same sex) will be sourced from a commercial feedlot, where they will be supplemented with NaturSafe® (12 g/hd/d or 4 lb/ton; Diamond V Mills, Cedar Rapids, IA) or with a Control ration (n = 16 per treatment). Following at least 28 days of supplementation, calves will be transported to the Livestock Issues Research Unit’s Bovine Immunology Research and Development Complex in Lubbock, TX (day -2). Upon arrival, calves will be placed in outdoor, covered holding pens with access to water and treatment rations overnight (LIRU-B2 SOP). The following day (day -1) calves will be processed through an indoor working facility where they will be fitted with indwelling jugular catheters (LIRU-B1 SOP) and rectal or vaginal temperature recording devices (LIRU-B3 or B-4 SOP) that will measure body temperature continuously at 5-min intervals. Following these procedures, calves will be placed in individual bleeding stalls for the duration of the challenge, and with access to water and their treatment ration. On day 0, all calves will be challenged intravenously with lipopolysaccharide (LPS; 0.25 µg/kg body weight). Whole blood samples will be collected for serum isolation every 0.5 h from -2 to 8 h and again at 24 h relative to LPS administration at 0 h. Serum will be isolated and stored at -80oC until analyzed for serum cortisol, pro-inflammatory cytokines [tumor necrosis factor-a (TNF-a), interleukin-6 (IL-6) and interferon-' (IFN-')], haptoglobin, fibrinogen, and serum amyloid a. An additional whole blood sample will be collected every 2 h from -2 to 8 and again at 24 h for measuring hematology parameters (red blood cells, hemoglobin, hematocrit, platelets, and total white blood cells and differentials). Additionally, health scores (every 0.5 h, see below Sickness Score Data Sheet), and respiration rates (every 2 h) will be recorded from -2 to 8 h. Following collection of the 24 h sample, calves will be released from their bleeding stalls and processed through the working facility where jugular cannulas and temperature devices will be removed. Calves will then be placed in the outdoor pens with access to feed and water for at least 48 h prior to their transport back to the original feedlot.
