Two experiments were conducted to determine the effect of a single or multiple intramuscular (i.m.) injection of
ketoprofen and
castration technique on physiological and behavioral indicators of
pain in beef calves. A total of 150 bull calves (284.8 ± 22.7 kg BW) were used in both experiments, each 1 conducted as a 3 × 2 factorial design, where main factors included
castration technique--no
castration (CT), surgical (SU), or band (BA)--and drug administration--physiological
solution (PS) or i.m. injection of
ketoprofen (KP; 3 mg Anafen/kg BW) in the neck of calves. Animals were weighed weekly during the experiment to calculate ADG. Behavioral responses indicative of
pain and discomfort during the
castration procedure were documented using a visual analog score (VAS) by an experienced observer who was blind to the treatments. Movements of the animals in the chute during
castration were quantified using a strain gauge system mounted on the head gate to evaluate the escape response of the cattle. Pens were equipped with an automated feed bunk monitoring system enabling feed intake and feeding behavior to be continuously monitored for each individual. Thermographic images of the scrotal area were evaluated 24 and 0.5 h before
castration, 0.5, 1, 24, 48, and 270 h postcastration, and weekly thereafter until the end of the trial. Blood samples were obtained postcastration to evaluate changes in total white blood cell (WBC) count and neutrophil-to-lymphocyte (N:L) ratio. Saliva samples were taken 24 and 0.5 h before
castration, immediately after
castration, and 0.5, 1, 2, 5, 24, and 48 h and then 5, 7, and 14 d after
castration to determine
cortisol concentration. Scrotal temperature, VAS, total WBC, N:L ratio, salivary
cortisol, mobility, and pressure exerted in the chute were greater (P < 0.05) and ADG and feed intake were lower (P < 0.05) in SU than in CT animals within the first week after
castration. Also, BA calves had a greater (P < 0.05) scrotal temperature around wk 4 after
castration and a lower feed intake and ADG at wk 2 and 3 and wk 6 and 7 after
castration, respectively, compared to CT. Treatment KP had limited effects on reducing the indicators of
pain associated with SU or BA, suggesting that further studies will be needed to assess the posology of the i.m. administration of
ketoprofen to improve the consistency of its effects as a
pain mitigation strategy after
castration.