Abstract #505

# 505
Acute and chronic stress models differentially affect the inflammatory and antibody titer responses to respiratory vaccination in naïve beef steers.
Nathan D. May*1, Jeff A. Carroll2, Nicole C. Burdick Sanchez2, Shelby L. Roberts1, Heather D. Hughes1, Paul R. Broadway2, Kate P. Sharon3, Michael A. Ballou3, John T. Richeson1, 1West Texas A&M University, Department of Agricultural Sciences, Canyon, TX, 2USDA-ARS, Livestock Issues Research Unit, Lubbock, TX, 3Texas Tech University, Department of Food and Animal Sciences, Lubbock, TX.

The objective of this research was to determine the effect of an acute vs. chronic stress model on serum antibody titer and acute phase responses. Seronegative beef steers (n = 32; 209 ± 8 kg) were stratified by BW and assigned randomly to 1 of 3 treatments (1) Chronic stress (CHR), 0.5 mg/kg BW dexamethasone (DEX) administered i.v. at 1000h on d −3 to 0; (2) Acute stress (ACU), 0.5 mg/kg BW DEX administered i.v. at 1000h on d 0 only; or (3) Control (CON), no DEX. On d −4, steers were fitted with jugular catheters and placed into individual stanchions in an environmentally controlled facility. At 1200h on d 0, steers were administered a modified-live virus respiratory vaccine containing isolates of infectious bovine rhinotracheitis virus (IBRV), bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV) and parainfluenza-3 virus (PI3V). On d 4, cattle were transported (177 km) to an isolated facility and housed in a single pen. Serum was harvested from d 0, 7, 14, 21, 28, 35, 42, and 56 and subsequently used to determine IBRV-, BVDV-, BRSV-, and PI3V-specific antibody titers. Additionally, serum from d −2, 0, 1, 3, 7, and 14 was used to quantify haptoglobin (Hp) and ceruloplasmin (Cp) concentrations. There was a trt × d interaction (P < 0.01) such that CHR steers had a greater (P ≤ 0.07) BVDV antibody titer from d 14 to 28; whereas, CHR was greater (P = 0.06) than ACU on d 56. Moreover, IBRV antibody titers were increased beginning on d 14 for CHR and d 28 for ACU, and remained elevated through d 56 compared with CON (P ≤ 0.03). Stress treatment altered Hp such that CON exhibited a greater (P < 0.01) Hp concentration than CHR but was not different from ACU (P = 0.16). On d 3, Cp was greatest for CON, intermediate for ACU, and least for CHR (trt × d; P ≤ 0.01). Results suggest that immunosuppressive conditions in CHR and ACU may have allowed enhanced viral replication from the vaccine, resulting in a greater antibody titer response. Data further indicate that DEX administration blunted the acute phase response and these alterations were particularly evident in the CHR stress model.

Key Words: cattle, stress, vaccination