EFFECT OF SUPPLEMENTAL CHROMIUM ON ANTIBODY-RESPONSES OF NEWLY ARRIVED FEEDER CALVES TO VACCINES AND OVALBUMIN

Two trials were conducted to investigate the effects of supplemental c hromium (Cr) from organic sources (Cr chelate and high Cr yeast) on an tibody responses of newly arrived feeder calves following vaccination with infectious bovine rhinotracheitis (IBR), parainfluenza-3 (PI,), b ovine respiratory syncytial virus (BRSV), bovine viral diarrhea (BVD) and Pasteurella haemolytica and ovalbumin (OVA). Using cross bred stee r calves purchased at sales in Ontario, vaccines and OVA were given on d 0 and 21 after arrival in the feedlot. Immune responses of calves w ere measured as serum specific antibody titres against all antigens on d 0 and 28 or d 35. The anti-OVA antibody responses (trial 2) were fu rther investigated by measuring antibody concentrations of calves week ly until d 55 after arrival in the feedlot. Supplemental Cr (0.14 ppm) from an amino acid-chelated source had no effect on antibody response s to IBR, PI3 and BRSV, but enhanced (P < 0.05) antibody titres of cal ves in response to the BVD vaccine on d 28 or d 35. Supplemental Cr fr om Cr yeast had no effect on antibody titres of calves to any vaccines . Chromium from both sources (trial 1 and 2) had no affect on antibody responses of calves following vaccination with P. haemolytica. Howeve r, supplemental Cr (0.75 ppm) from Cr yeast enhanced (P < 0.05) serum antibody responses of calves to OVA during the primary response (d 14) and secondary response (d 35) following immunization. These data conf irmed our previous finding that supplemental Cr can enhance humoral im mune response of market-transit stressed calves, but its enhancement o n vaccine efficacy was antigen-dependent and variable.