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

Abstract

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 reducing postcastration stress. With differences between treatments, HCC shows promise as a technique for measuring long-term stress in beef cattle.