Efficacy of pain management for cattle castration: a systematic review and meta-analysis.

Most publications focused on surgical castration (n = 14), and the most frequently outcome reported was blood cortisol (n = 13). None of the included studies were assessed as having a low risk of bias, mostly due to a lack of reporting blinding procedures and reasons for missing data. We used a three-level random effect model fitted at 1, 3, 4, 6, 12 and 24 h after castration to meta-analyze the effect of surgical castration on blood cortisol.

Multimodal analgesia reduced blood cortisol concentrations in the first hour following surgical castration in comparison to the control group (-40.8 nmol/L; 95% CI: -51.4, -30.1); this effect was diminished but still evident at 3 and 4 h after castration. Too few data were available to meaningfully assess other outcomes and methods. The variability in the choice of methods and outcomes between studies, as well as the risks of bias, hinders capacity to provide science-based recommendations for best practice.