Reduction of stress and increased weight gain with Capsaicin–Lidocaine in piglet castration

Abstract

Surgical castration in piglets is a common management practice in swine production; however, it induces acute pain and stress that negatively affect animal welfare and productive performance. This study evaluated the effectiveness of capsaicin (0.075%) combined with lidocaine (2%) as a local anesthetic during piglet castration at 5 and 21 days of age. A quantitative experimental study with a randomized complete block design was conducted using 18 piglets, divided into a control group and two treatment groups receiving different doses of capsaicin (0.5 g and 0.9 g) plus lidocaine. Plasma cortisol concentration and daily weight gain were analyzed as physiological and productive indicators. Results showed that piglets castrated without anesthesia exhibited a marked increase in cortisol levels and intense pain-related behaviors, whereas treated groups showed a significant reduction in stress indicators. Notably, the higher dose of capsaicin reduced cortisol levels below baseline and improved daily weight gain in both age groups. These findings demonstrate that the capsaicin–lidocaine combination is an effective strategy to mitigate pain, improve animal welfare, and enhance productivity in swine production systems.