Location: Livestock Issues ResearchTitle: Bovine respiratory disease: Sex matters
|Carroll, Jeffery - Jeff Carroll|
|WORD, ALYSSA - Texas Tech University|
|LITTLEJOHN, BRITTNI - Texas A&M University|
|PAULUS COMPART, DEVAN - Pmi Nutritional Additives|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2018
Publication Date: 7/29/2019
Citation: Sanchez, N.C., Broadway, P.R., Carroll, J.A., Word, A.B., Littlejohn, B.P., Paulus Compart, D.M. 2019. Bovine respiratory disease: Sex matters. Journal of Animal Science Supplement. 96(Suppl3):23-24.
Technical Abstract: To evaluate a potential sexual dimorphic innate immune response to respiratory disease, 8 steers and 7 heifers (BW=280±4 kg) were subjected to a combined viral-bacterial respiratory disease challenge utilizing BHV-1 (intranasal; 1.0x10^8 PFU/mL/nostril) at -72h and Mannheimia haemolytica (MH; intratracheal; 1.3x10^7 CFU/hd) at 0h. Following MH administration, serum was collected every h for 8h, and every 12h from 12 to 72h, and at 168h and was analyzed for cytokines. Whole blood was analyzed every other h from 0 to 8h, every 12h from 12 to 72h, and at 168h for hematology variables. Body temperature, measured from -72 to 69h via indwelling rectal or vaginal temperature monitoring devices, was greater in steers compared to heifers (40.06 vs. 39.60±0.11oC; P=0.008). Serum IL-4 was greater in steers than heifers (14.7 vs. 2.8±2.7 pg/mL; P=0.007), while there was no difference (P=0.10) in IL-6 or IFN-gamma. There was a tendency (P=0.09) for a treatment by time interaction for total white blood cells (WBC), such that WBC were greater in steers than heifers at -72h, but were reduced in steers compared to heifers from 36 to 60h post-MH challenge. Neutrophils were elevated in steers compared to heifers from 0 to 4h, at 6h, and from 8 to 12h, but were reduced in steers compared to heifers at 168h (P=0.02). Lymphocytes were reduced in steers compared to heifers at 12h and from 36 to 60h post-MH (P<0.001). The neutrophil:lymphocyte ratio was elevated in steers compared to heifers from 2 to 36h post-MH, but was reduced in steers compared to heifers at 168h (P<0.001). Monocytes were reduced in steers compared to heifers from 24 to 60h post-MH (P=0.005). These data demonstrate distinct differences in the innate immune response following a BRD challenge such that steers produced an early response while the response in heifers was delayed.