Immune responses and performance are influenced by respiratory vaccine antigen type and stress in beef calves

Authors: HUDSON, RACHEL - West Texas A & M University; TOMCZAK, DEXTER - West Texas A & M University; KAUFMAN, EMILY - West Texas A & M University; ADAMS, ASHLEE - West Texas A & M University; Carroll, Jeffery - Jeff Carroll; Broadway, Paul; BALLOU, MICHAEL - Texas Tech University; RICHESON, JOHN - West Texas A & M University

Submitted to: Animals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2020
Publication Date: 6/30/2020
Citation: Hudson, R.E., Tomczak, D.J., Kaufman, E.L., Adams, A.M., Carroll, J.A., Broadway, P.R., Ballou, M.A., Richeson, J.T. 2020. Immune responses and performance are influenced by respiratory vaccine antigen type and stress in beef calves. Animals. 10(7):1119. https://doi.org/10.3390/ani10071119.
DOI: https://doi.org/10.3390/ani10071119

Interpretive Summary: This study was a collaborative effort between scientists from West Texas A&M University, the Livestock Issues Research Unit, and Texas Tech University to study the effects of acute versus chronic stress on the antibody, endocrine, and hematological responses to vaccine administration. Prevention of disease by vaccination is a cornerstone of animal health management. Nearly all cattle are vaccinated with bovine viral diarrhea virus (BVDV; 95.1%) and infectious bovine rhinotracheitis virus (IBRV; 93.2%) antigens upon arrival in U.S. feedlots. However, stress experienced by cattle upon maternal separation and relocation to a stocker or feedlot facility can result in immunosuppression, and vaccination at this time may impact the immune response of calves to vaccine agents. The current study objective was to determine the effect of an acute (ACU) or chronic (CHR) physiological stress model on immunological, endocrine, and acute phase protein (APP) responses in beef calves administered pentavalent respiratory vaccines containing replicating modified-live viruses or non-replicating killed viruses. Our hypothesis was that immune, endocrine, and APP responses are differentially altered by ACU and CHR stress model and vaccine antigen type. Results revealed some alterations in antibody response, APP, endocrine, and hematological variables from implementation of ACU or CHR stress model and vaccination with killed-virus (KV) or modified-live virus (MLV) vaccine. Antigen-specific antibody titer results suggest that KV had a greater antibody response against PI3V and IBRV antigens, whereas MLV had a greater antibody response against BVDV. Stress model implementation yielded inconsistent results to antibody titer concentrations such that BRSV-specific antibody response was delayed in CHR and BVDV-specific antibody response was greater in ACU. The CHR model appeared to cause greater stress-induced immunosuppression because increased neutrophils were observed following stress model implementation and lymphocytes and eosinophils were reduced, despite overall greater cortisol detected for ACU. Further research investigating the interaction between stress-induced immunosuppression and concurrent use of different vaccine types is needed to better define the safe and efficient use of respiratory vaccines in cattle. These data will be of interest to researchers in the field of immunology and stress physiology, as well as bovine veterinarians and cattle producers.

Technical Abstract: The study objective was to determine if acute (ACU) or chronic (CHR) stress models affected antibody, endocrine, or hematological responses to modified-live virus (MLV) or killed virus (KV) respiratory vaccination in beef steers. A total of 48 calves (d 0 BW = 226 ± 6.2 kg) from a single origin were used in a 2 × 2 factorial design to evaluate main effects of stress model, vaccine type and their interaction; resulting in 4 treatments (n = 12/treatment) consisting of ACU with KV (ACUKV), ACU with MLV (ACUMLV), CHR with KV (CHRKV), and CHR with MLV (CHRMLV). The ACU calves were weaned at the origin ranch on d -37 and transported 472 km to the study site on d -21 for acclimation. The CHR calves were weaned on d -3, transported 460 km to a research facility near Lubbock, TX on d -2, and transported 164 km to the study site on d -1 to mimic the beef cattle marketing process. Vaccines were administered on d 0 and KV was revaccinated on d 14. Animal was experimental unit and dependent variables were analyzed using PROC MIXED with repeated measures (d). Vaccination with KV elicited a vaccine type × d (P < 0.01) interaction with increased (P = 0.01) PI3V- and IBRV-specific antibody titers on d 21; conversely, MLV calves had increased (P = 0.01) BVDV titers on d 14, 28, 35, 42, 49, and 56. Increased (P = 0.05) BRSV titers were observed in a stress model × d (P < 0.01) interaction for CHR calves on d 21, 28, 36, and 42; however, ACU exceeded CHR calves in BVDV-specific antibody concentration on d 21, 28, and 49. A d effect (P < 0.01) was observed for Hp with greatest (P ' 0.01) concentration on d 3. Serum cortisol concentration was greater (P = 0.04) for ACU vs. CHR calves on d -2, 0, 1, 3, and 5. Total leukocytes were decreased for CHR vs. ACU on d 0, 1, 3, 5, 7, 14 and 21 (P = 0.02). A reduction (P = 0.04) in total leukocyte count was observed for MLV on d 5, 7, and 14 vs. KV. Neutrophils and neutrophil:lymphocyte were markedly increased (P = 0.01) for CHR on d -2; whereas, neutrophils were decreased (P = 0.01) on d 1 and 21 for CHR. Monocytes were decreased on d 1, 5 and 7 for MLV (P = 0.04) and d -2 to 14 for CHR (P = 0.03). Eosinophils were reduced (P = 0.007) for CHR vs. ACU on d -2, yet a rebound response (P = 0.03) was noted on d 0 such that eosinophils were 0.288 and 0.160 K/µL for CHR and ACU, respectively. Results indicate CHR stress model and MLV vaccination may have more profoundly induced immune dysfunction in beef calves.