|Schwertner, Luke -|
|Galyean, Mike -|
|Ballou, Mike -|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: July 11, 2010
Publication Date: October 11, 2010
Citation: Schwertner, L., Hulbert, L.E., Carroll, J.A., Galyean, M., Ballou, M. 2010. Effects of source and level of energy on the immune competence and response to an Infectious Bovine Rhinotracheitis Virus (IBRV) challenge in cattle. [abstract]. 2010 American Society of Animal Science Meeting, July 11-15, 2010, Denver, CO. Journal of Animal Science. 88(E-Supplement 2):T15. Technical Abstract: Objectives were to evaluate how dietary energy level and source affect immune competence and response to a viral challenge in cattle. Forty-eight crossbred beef steers were stratified by BW within 2 periods and randomized to 1 of 3 dietary treatments (8 steers/treatment within period). Treatments were: a 70% concentrate diet fed ad libitum (70AL); a 30% concentrate diet fed ad libitum (30AL); and 70% concentrate diet restricted to the NEg intake of 30AL (70RES). Ex vivo immune competences were evaluated after treatments were applied for 28 d, after which cattle were moved into individual pens (d 28 to 40) and intranasally challenged with IBRV on d 30. On d 34, all cattle were offered a 50% concentrate diet ad libitum until d 50. Both energy source (P < 0.02) and level (P < 0.04) affected peripheral blood mononuclear cell synthesis of tumor necrosis factor-alpha (TNF), with cell culture supernatant concentrations of TNF averaging 2,264, 1,241, and 1,887 pg/mL for 70AL, 30AL, and 70RES, respectively. Neither whole blood killing of Mannheimia haemolytica nor neutrophil oxidative burst in response to M. haemolytica were affected by treatments. Rectal temperature following IBRV peaked 3 d post challenge and returned to baseline by d 6, but it was not affected by treatment. After switching cattle to the 50% concentrate diet on d 4 after the IBRV challenge, there were no differences in DMI while the cattle were individually penned. When cattle were group-penned 10 d after the IBRV challenge, the 70RES cattle had greater DMI (P < 0.04). Following the IBRV challenge, serum glucose concentrations did not differ among treatments; however, the 70AL cattle had greater blood urea N concentrations (P < 0.01). There was a treatment x time interaction (P < 0.01) for NEFA, such that cattle fed the 70AL had elevated NEFA on d 3 and 5 after IBRV. Data indicate that cattle fed higher energy diets and to an extent a higher percentage of concentrates had a more pronounced pro-inflammatory response, but other aspects of innate immune competence were not influenced by level or source of energy.