Changes in physiological and immunological variables in weaned dairy calves exposed to different stressors

Authors: Sanchez, Nicole; KOHL, KESLEY - Texas Tech University; Broadway, Paul; Carroll, Jeffery; HALES, KRISTIN - Texas Tech University; LEGAKO, JERRAD - Texas Tech University; BARKER, SAMANTHA - Texas Tech University; DOBBINS, THOMAS - Texas Tech University; LOOMAS, KAITLYN - Texas Tech University; BRATCHER, CHRISTY - Mississippi State University

Submitted to: Translational Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/7/2025
Publication Date: 9/18/2025
Citation: Sanchez, N.C., Kohl, K.B., Broadway, P.R., Carroll, J.A., Hales, K.E., Legako, J., Barker, S.N., Dobbins, T.W., Loomas, K.R., Bratcher, C.L. 2025. Changes in physiological and immunological variables in weaned dairy calves exposed to different stressors. Translational Animal Science. 9. https://doi.org/10.1093/tas/txaf125.
DOI: https://doi.org/10.1093/tas/txaf125

Interpretive Summary: Cattle commonly experience stress during the production cycle. Stress can include transportation or exposure to disease. This study, conducted by scientists in Lubbock, TX and university collaborators, compared stress and immune responses of calves when exposed to acute immune stimulation, vaccination, or transportation. Study results found that differences exist in a calf’s response to different stressors. The largest changes were observed in calves exposed to acute immune stimulation and vaccination. These results provide additional information on the response of calves to various stressors. These data will be of interest to scientists studying cattle stress and health and cattle producers.

Technical Abstract: This study was conducted to investigate the effects of different stressors on physiological and innate immune variables in weaned dairy calves. Holstein steers (n = 40; 110 ± 11.8 kg body weight [BW]) were housed in individual pens in an environmentally controlled barn. Steers had ad libitum access to water and a starter ration. Steers were randomly allotted to four treatment groups (n = 10/treatment): 1) Control (CON), 2) Transport (TRANS; transported in a livestock trailer for 4 h), 3) Lipopolysaccharide (LPS; administered i.v. 0.10 µg /kg BW), and 4) Vaccine (VAX; administered a Mannheimia haemolytica toxoid vaccine). One day prior to administration of stressors, indwelling jugular vein catheters and rectal temperature (RT) recording devices were placed in all steers. Whole blood was collected at -1, -0.5, 0, 1, 2, 3, and 4 h relative to administration of stressors for serum, plasma, and hematology. There was a treatment × time interaction (P = 0.01) for all hematology parameters except for hemoglobin and platelets. Monocyte, lymphocyte, neutrophil, basophil, and white blood cell concentrations and the neutrophil:lymphocyte ratio were reduced (P < 0.02) in steers administered LPS compared to all other treatments. For steers administered the VAX treatment, white blood cell and neutrophil concentrations and the neutrophil:lymphocyte ratio increased (P < 0.04) 4 h post-treatment application compared to other treatments. There was a treatment × time interaction (P < 0.01) for the change in RT relative to baseline values. The change in RT increased following administration of LPS and peaked at approximately 3 h post-administration before decreasing to near baseline values. In contrast, RT began to increase 3 h post-treatment administration in steers administered the VAX treatment, where the greatest RT values were observed at 6 h post-treatment. There was a treatment x time interaction (P < 0.01) for cortisol concentrations, where steers administered LPS produced the greatest increase in cortisol compared to all other treatments. There was a treatment x time interaction (P = 0.02) for the change in interferon-aA, interleukin-1a, interleukin -1 F5, monokine induced by interferon-', macrophage inflammatory protein-1b, and tumor necrosis factor-a relative to baseline values. Concentrations of these cytokines remained greater in LPS and VAX steers compare to CON and TRANS. These data demonstrate the differential immune responses to common challenges experienced by dairy calves.