An investigation of hair cortisol as a measure of long-term stress in beef cattle: results from a castration study

The objectives were to (1) investigate the effectiveness of hair cortisol concentration (HCC) as a measure of long-term stress in beef cattle and (2) determine whether meloxicam would decrease postcastration stress. Bull calves on two farms [site 1: Hereford cross (n = 73); site 2: Black Angus (n = 85)] were assigned to three treatments: (1) surgical castration with saline (CS, n = 52), (2) surgical castration with meloxicam (CM, n = 54), and (3) sham castration with saline (S, n = 52), balanced for age. Hair was collected from the left hip on day 0, prior to castration, and day 14, after 2 wk of regrowth from the day 0 location. Standing time was recorded on 129 calves (CS = 47, CM = 42, S, = 40) from 0 to 7 d post castration. On day 14, CS calves had 13.8% greater HCC than S (P = 0.031) and tended to be higher than CM calves (P = 0.095); CM and S calves did not differ. Standing time did not differ between treatments. Lower HCC in CM compared with CS calves indicates that meloxicam may be effective at re...