Table 2.
Physiological responses during a 45-d feedlot receiving period of beef steers administered (BAS; n = 12) or not (CON; n = 12) a BAS at feedlot entry (day 0)1,2
| Item | CON | BAS | SEM | P-value |
|---|---|---|---|---|
| Hormones and metabolites2 | ||||
| Plasma BHBA, mg/mL | 2.75 | 3.23 | 0.12 | <0.01 |
| Plasma haptoglobin, mg/mL | 0.769 | 0.724 | 0.052 | 0.56 |
| Plasma NEFA, μEq/L | 0.273 | 0.291 | 0.018 | 0.48 |
| Hair cortisol, pg/mg of hair | 4.17 | 4.19 | 0.18 | 0.92 |
| Serum antibodies against respiratory viruses3 | ||||
| Parainfluenza-3 virus | 68.2 | 79.1 | 6.5 | 0.27 |
| Bovine respiratory syncytial virus | 98.8 | 111 | 10.5 | 0.43 |
| Bovine viral diarrhea viruses type I and II | 1.09 | 0.978 | 0.095 | 0.42 |
| Bovine herpesvirus-1 | 205.5 | 205.1 | 16.5 | 0.98 |
| Mannhemia haemolytica | 102 | 100 | 8 | 0.91 |
1Steers individually received 5 mL of a BAS (IRSEA Group, Quartier Salignan, France) or placebo (CON; diethylene glycol monoethyl ether) upon feedlot arrival on day 0. Treatments (5 mL) were applied topically to the nuchal skin area of each animal.
2Blood samples were collected on days 0, 7, 17, 31, and 45. Hair samples were collected on days 0, 17, 31, and 45 as in Schubach et al. (2017). Results from day 0 were used as covariate in each respective analysis.
3Steers received vaccination against respiratory pathogens on day 1 (Vista Once SQ; Merck Animal Health, Madison, NJ). Samples collected on days 0, 17, 31, and 45 were analyzed and results expressed as sample:positive control ratio as in the study by Cooke et al. (2020c). Results from day 0 were used as covariate in each respective analysis.