Effect of castration and dehorning singularly or combined on the behavior and physiology of Holstein calves

The objectives of this study were to determine i) the effect of castration, dehorning, or both on the physiology and behavior of 3-mo-old Holstein calves, and ii) the effectiveness of pain relief to alleviate the pain caused by castration and/or dehorning. Holstein calves (n = 80) were assigned randomly to 1 of 8 treatments (10 calves/treatment): i) control handling (SHAM); ii) surgical castration (CAS); iii) dehorning (DH); iv) surgical castration and dehorning (CD); v) control handling plus pain relief (ANA); vi) surgical castration plus pain relief (CAS+A); vii) dehorning plus pain relief (DH+A); or viii) surgical castration and dehorning plus pain relief (CD+A). Pain relief consisted of administering local anesthetic and a nonsteroidal anti-inflammatory drug (NSAID) immediately before castration, dehorning, or both. Sequential blood samples were collected to measure leukocyte counts and cortisol concentrations. Behavior was recorded using 5-min scan samples during the first 3 h after application of the treatments. Calves were weighed before and 24 h after treatment application. Calves dehorned spent more time head shaking (P < 0.001) and ear flicking (P < 0.05), and CD calves spent more time ear flicking (P < 0.05) and foot stamping (P < 0.01) than SHAM handled calves. Calves castrated, dehorned, or both spent less (P < 0.01) time eating compared with SHAM handled calves. Giving calves pain relief before castration and/or dehorning increased (P < 0.05) the time spent eating compared with CAS, DH, and CD calves. At 6 h posttreatment, neutrophil to lymphocyte ratio was greater (P < 0.01) in castrated and/or dehorned calves compared with SHAM-handled calves. Castration and/or dehorning also increased (P < 0.05) cortisol concentrations for at least 4 h after these procedures were performed; however, administering pain relief before castration and/or dehorning markedly reduced (P < 0.05) this response. Behavioral and physiological changes caused by castration, dehorning, or both are indicative of calves experiencing pain for at least 4 h after application of these procedures, and these responses were additive when performed together. Therefore, providing calves with pain relief, in the form of local anesthetic and an NSAID, can markedly reduce both the behavioral and physiological response to these procedures.