Comparison of hot-iron and freeze branding on cortisol levels and pain sensitivity in beef cattle

Abstract

Thirty yearling (450–500 kg) heifers of mixed breeds (Hereford, Charolais, Angus and Shorthorn) were habituated to handling over a 14 ± 2 d period before branding and were fitted non-surgically with jugular catheters 1 before branding. On the day of branding, heifers were assigned to hot-iron brand (H), freeze brand (F), or control (C) treatments according to a predetermined randomized branding order (n = 10 per treatment). Blood samples were obtained at 20 and 0 min before and 20, 40, 60, 80, 100, 120, 140, 160 and 180 min after application of branding treatments. To detect stress-induced analgesia, each animal's sensitivity to pain was assessed by measuring the time it took them to respond to a thermal energy source (laser) applied to their hind legs. Foot-lift latencies were obtained 0, 10, 20, 60 and 120 min after the treatments were imposed. Sensitivity to touch also was assessed 1 and 7 d after branding by placing pressure on the brand site and measuring the amount of movement by the animals. Both H and F heifers had higher mean plasma cortisol concentrations than C animals 20 and 40 min after branding (P < 0.05). However, hot branding was found to cause a more pronounced cortisol response than freeze branding at 40 min (P < 0.05). No treatment differences in foot-lift latencies or sensitivity to touch were observed. Both branding methods cause discomfort in cattle; however, hot branding appears to cause a greater acute response than freeze branding. Key words: Branding, cattle, cortisol, stress-induced analgesia