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R. W. Godfrey, S. R. Joseph, J. A. Martinez, H. C. Nelthropp, S. A. Lakos, R. L. Stanko, H. G. Kattesh, S. A. Lockwood, B. E. Gillespie, 069 Evaluation of the Effect of Hot Iron Branding on Cortisol and Cortisol Binding Globulin Concentrations in Young Senepol Cattle, Journal of Animal Science, Volume 95, Issue suppl_1, December 2016, Pages 34–35, https://doi.org/10.2527/ssasas2017.069
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Abstract
The objective was to evaluate the impact of hot iron branding on plasma cortisol and corticosteroid- binding globulin (CBG) concentrations of Senepol heifers and bulls (n = 15/sex; 14 mo of age). On d 1 and 14 calves were put in the chute and after applying squeeze a blood sample was collected by coccygeal vessel puncture (PRE). After 1 min to mimic the time it takes to brand a second blood sample was collected (POST). The calf was released from the chute. On d 7 calves were put in the chute and after applying squeeze to immobilize the calf a blood sample was collected by coccygeal vessel puncture (PRE). The calves were hot branded with a single digit (number 5) using an electric branding iron. A second blood sample was collected after branding was completed (POST). The calf was released from the chute and returned to the pen of same sex cohorts. Plasma was harvested from blood samples and stored at -20 °C until assayed for cortisol and CBG by RIA and ELISA, respectively. Free cortisol index (FCI) was determined as the ratio of total cortisol/CBG. Data was analyzed using SAS (9.3) with sex, week and time of sampling in chute as the main effects. Cortisol was higher (P < 0.0001) in heifers than in bulls (101.44 ± 3.99 vs. 74.88 ± 3.97 nmol/L, respectively). In bulls cortisol was lower on d 7 compared to d 1 and 14 (50.97 ± 6.88 vs. 87.19 ± 6.88 vs. 86.48 ± 6.88 nmol/L, respectively) but there was no difference (P > 0.10) in heifers over time. Cortisol was lower (P < 0.05) in the PRE than in the POST sample (82.45 ± 3.99 vs. 93.87 ± 3.97 nmol/L, respectively). Heifers had higher (P < 0.0002) CBG than bulls (0.81 ± 0.04 vs. 0.62 ± 0.04 mg/L, respectively). There was no difference in CBG across days or between PRE and POST samples (P > 0.10). On d 7 FCI of bulls was lower (P < 0.0005) than on d 1 and 14 (83.14 ± 17.54 vs. 157.64 ± 17.54 vs. 195.62 ± 17.54 nmol/mg, respectively). In heifers there was no difference (P > 0.10) in FCI across days or between PRE and POST. These results show that hot branding elicits a slight, acute cortisol response (13.8 % increase) in Senepol cattle but there was no residual impact 7 d after branding.
