Acute physiological responses to castration-related pain in piglets: the effect of two local anesthetics with or without meloxicam

Abstract

Methods to reduce castration-related pain in piglets are still issues of concern and interest for authorities and producers. Our objectives were to estimate the effectiveness of two protocols of local anesthesia (lidocaine and the combination of lidocaine + bupivacaine) as well as the use of meloxicam as a postoperative analgesic in alleviating castration-related pain, measured by acute physiological responses. Eight groups (15 piglets/group) were included in the study: (1) castration without anesthesia or analgesia, without meloxicam (TRAD WITHOUT), (2) castration without anesthesia or analgesia, but with meloxicam (TRAD WITH), (3) handling without meloxicam (SHAM WITHOUT), (4) handling with meloxicam (SHAM WITH), (5) castration after local anesthesia with lidocaine but without meloxicam (LIDO WITHOUT), (6) castration after local anesthesia with lidocaine and meloxicam (LIDO WITH), (7) castration after local anesthesia with lidocaine + bupivacaine without meloxicam (LIDO + BUPI WITHOUT), (8) castration after local anesthesia with lidocaine + bupivacaine and meloxicam (LIDO + BUPI WITH). Acute physiological responses measured included skin surface temperature and serum glucose and cortisol concentrations. On days 4 and 11 post-castration BW was recorded and average daily gain was calculated over this period. Furthermore, piglet mortality was recorded over the 11-day post-castration period. Administration of local anesthetic or meloxicam did not prevent the decrease in skin surface temperature associated with castration. Lidocaine reduced the increase in glucose concentration associated with castration. For castrated pigs, the joint use of lidocaine and meloxicam caused a significant decrease in cortisol concentration; the combination of intratesticular lidocaine and bupivacaine did not seem to be more effective than lidocaine alone. No effect of treatments on mortality and growth were detected.

Influences of Immunocastration on Endocrine Parameters, Growth Performance and Carcass Quality, as Well as on Boar Taint and Penile Injuries

“…It is well-known that surgical castration without anesthesia is a painful procedure [1,[18][19][20][21] and numerous investigations concerning alternatives, like GnRH vaccination or boar fattening already exist [22][23][24]. However, there are open questions yet to be answered.…”

Optimization of analgesia for piglet castration under isoflurane anaesthesia with parenteral butorphanol, meloxicam or intratesticular lidocaine

“…In contrast, piglets receiving lidocaine IT compared to no analgesia or meloxicam only, showed a lower increase in postoperative plasma cortisol levels (Kluivers-Poodt et al, 2012). An even better outcome was seen in a recently published study using a combination of parenteral meloxicam and IT and subcutaneous lidocaine (Bonastre et al, 2016).…”

Why Pain Is Still a Welfare Issue for Farm Animals, and How Facial Expression Could Be the Answer

“…Devant et al [53], noted feed intake declined after castration, as did lying behavior and overall activity levels. Bonastre et al [91], assessed the physiological responses of piglets to castration, finding surface skin temperatures to drop immediately after castration independent of any anesthesia or analgesia given. They also found glucose concentration to increase in response to castration, and cortisol concentrations to differ in response to castration with or without anesthesia and analgesia.…”

“…When managing pain, a multimodal approach is required [91,139]. Thought needs to be given as to the cause of the pain; if it is caused by a disease then treatment to eliminate the causative agent may be the best course of action.…”