Search

Objective: This study assessed the use of a topical anesthetic as a feasible approach to reduce pain during piglet castration using a minimal anesthesia protocol., Animals: 18 male piglets, aged 3-6 days, were included in this study., Methods: A minimal anesthetic state was induced with isoflurane administered by facemask, with anesthetic depth individually adjusted based on responses to interdigital pinch. To desensitize the scrotal skin, a vapocoolant was applied 3 times. Scrotal incisions were made subsequently and Tri-Solfen (TS) or Placebo (P) was administered in both incisional gaps. After 30 seconds, the spermatic cords were severed followed by a further application of TS/P to both incision edges. Nociception-related variables, such as mean arterial blood pressure (MAP), heart rate (HR), and nocifensive movements, were assessed., Results: Significant differences in MAP changes were assessed between the TS (14 ± 4 mmHg) and the P group (36 ± 8 mmHg) for cutting the spermatic cords. Furthermore, significantly fewer nocifensive movement score points appeared in the TS than in the P group (0; IQR = 0 vs 5; IQR = 6)., Clinical Relevance: In this anesthesia model, the application of TS after skin incision significantly reduced MAP responses and nocifensive movements with spermatic cord transection compared with the application of P. However, the waiting period between TS-application and spermatic cord transection might limit the benefit of the method in conscious piglets, as pain during castration is reduced but additional stress is caused by the prolonged handling. Furthermore, using a vapocoolant did not provide anesthesia for skin incisions.

Surgical castration of male piglets without analgesia is a painful procedure. This prospective, randomized and double-blinded study aimed to evaluate the analgesic effects of four different local anesthetics for piglet castration during the first week of life. In total, 54 piglets aged 3 to 7 days were distributed into 6 treatment groups: handling (H); castration without pain relief (sodium chloride, NaCl); and castration with a local anesthetic: 4% procaine (P), 2% lidocaine (L), 0.5% bupivacaine (B) or 20 mg/ml mepivacaine (M). By excluding stress and fear as disruptive factors via a minimum anesthesia model, all piglets received individual minimum alveolar concentration (MAC) isoflurane anesthesia. Twenty minutes before castration, all treatment groups except group H received one injection per testis. Then, 0.5 ml of a local anesthetic or NaCl was injected intratesticularly (i.t.), and 0.5 ml was administered subscrotally. Acute physiological responses to noxious stimuli at injection and castration were evaluated by measuring blood pressure (BP), heart rate (HR), cortisol, epinephrine, norepinephrine and chromogranin A (CgA); limb movements were quantified. The results confirm that castration without analgesia is highly painful. Surgical castration without pain relief revealed significant changes in mean arterial blood pressure (MAP) and HR. Local anesthetic administration significantly reduced changes in BP and HR associated with castration. Piglets receiving a preoperative local anesthetic exhibited the fewest limb movements during castration, while the NaCl group exhibited the most. Injection itself was not associated with significant changes in MAP or HR. However, many piglets exhibited limb movements during injection, indicating that the injection itself causes nociceptive pain. No significant differences were found between groups regarding parameters of plasma cortisol, catecholamines and CgA. In conclusion, all four local anesthetics administered are highly effective at reducing signs of nociception during castration under light isoflurane anesthesia. However, injection of a local anesthetic seems to be painful., Competing Interests: The authors have declared that no competing interests exist.

Objective: Comparison of the effectiveness of local anaesthesia (LA) in piglet castration with the combination of scrotal and inguinal application of procaine 2 % and lidocaine 5 % to the intratesticular application of lidocaine 1 % using following parameters: adrenaline (A), noradrenaline (NA), defensive movements and coordinated movement patterns., Material and Methods: In 2 substudies 232 male suckling piglets (3-6 days of age) were randomly allocated to study groups. In groups L5 and group P2 lidocaine 5 % and procaine 2 % was applied inguinally and scrotally, respectively, while piglets of groups H (handling) and K (castration without local anaesthesia) were only fixated as for an injection. In group L1 lidocaine 1 % was injected intratesticularly. After 30 min piglets were were castrated, whereas animals of group H were again only fixated. In substudy 1 (n = 112) blood samples were taken to determine the concentration of catecholamines after castration. During injection and castration defensive movements were judged. In substudy 2 (n = 120) piglets completed a chute to document the individual stress level., Results: Groups H and L1 demonstrated significantly less defensive movements during fixation for injection/injection compared to the other study groups (p ≤ 0.05). After the injection piglets of group P2 had significantly more difficulties in the chute and needed > 50 % more time to complete the course. In all study groups defensive movements during castration were the highest at the moment of severing the spermal cord. Group K obtained the highest possible rating of 8 and differed significantly from the other groups as well as when cutting the skin (p ≤ 0.05). Both the concentration of A and NA significantly rose in all groups. The increase in A and NA was significantly higher in group 2, as well as the increase in NA in group K, both in comparison to the other study groups (p ≤ 0.05)., Conclusion: None of the applied techniques for local anaesthesia achieved a complete elimination of pain during castration of suckling piglets. The behaviour analysis indicated an altogether higher distress for P2. After castration, this injection led to a neuroendocrine pain reaction that was comparable to or higher than that of group K. In both lidocaine groups (L1, L5) the pain reaction after castration tended to be lower. These results provide approaches to apply longer acting LA with a higher analgesic potency in an appropriate dosage and with an appropriate method of application., Competing Interests: Die Autoren bestätigen, dass kein Interessenkonflikt besteht., (© Georg Thieme Verlag KG Stuttgart · New York.)

Objective: Comparison of the effectiveness of local anaesthesia (LA) in piglet castration by procaine 2 % and lidocaine 5 % both through combined inguinal and scrotal application as well as by intratesticular application of lidocaine 1 %. The parameters used were serum cortisol and chromogranin A (CgA) concentrations as well as wound healing, body weight and animal losses., Material and Methods: In 2 substudies, a total of 232 male piglets aged 3-6 days were included. Substudy 1 (112 piglets): Group H: fixation of piglets as for an injection; group L5: inguinal and scrotal injection of lidocaine 5 %; group P2: inguinal and scrotal injection of procaine 2 %; group L1: intratesticular injection of lidocaine 1 %. In all the groups, blood samples were taken 45 minutes before and 30 minutes post-injection (p. i.). Substudy 2 (120 piglets): Group H: handling only as for an injection and castration; group K: handling as for an injection and castration without LA after 30 minutes. Groups L5, P2 and L1: management as in substudy 1 and castration after 30 minutes. Blood samples were taken 75 minutes before as well as 30, 60 and 240 minutes post-castration (p. c.). The evaluated parameters were serum cortisol and CgA concentrations, wound healing, body weight and piglet losses., Results: Substudy 1: The elevation of the cortisol and CgA concentrations in group P2 p. i. were significantly higher than in the other groups. The mean total cortisol concentration of group P2 p. i. was significantly higher than those of the other groups. Substudy 2: At 30 minutes p. c., all the groups displayed a significant increase in the cortisol concentration compared to group H. In group P2, the highest total cortisol concentration was measured 60 minutes p. c. and the elevation of the cortisol level was significantly higher than in the other groups. In group L1, a significantly greater increase in the CgA level was observed at 60 minutes p. c. when compared to the other groups. Regarding wound healing, body weight and losses, there were no significant differences between the groups., Conclusion: The combined inguinal and scrotal injection of procaine 2 % induced a greater neuroendocrine stress response than the inguinal and scrotal injection of lidocaine 5 % and the intratesticular injection of lidocaine 1 %. LA using procaine 2 %, lidocaine 5 % or lidocaine 1 % did not completely eliminate pain during castration. Castration under LA with procaine 2 % induced a greater pain reaction than castration without LA. Both groups castrated with LA using lidocaine (L1, L5) tended to display lower pain responses after castration than group K. On the basis of the findings of this study, other local anaesthetics that have a stronger effect could be further investigated according to their pain-killing effects in an appropriate application route., Competing Interests: Die Autoren bestätigen, dass kein Interessenkonflikt besteht., (© Georg Thieme Verlag KG Stuttgart · New York.)

Objective of this study was to examine the efficacy of various local anaesthetics (Procaine Hydrochloride, Procaine Hydrochloride + Epinephrin, Lidocaine Hydrochloride) used in castration of four to six day old male piglets. Animals of the control groups (I-IV) were treated analogous to the castration groups (V-IX) but not castrated. In groups I and V 15 minutes prior to castration/fixation the piglets were fixed as for injection but not medicated. The injection volume was standardised to 0.5 ml per testes. Local anaesthetics were applicated intratesticularly in five groups and intrascrotarly in two groups. Blood samples were taken shortly before and one, four and 24 hours after castration/fixation. The serum cortisol level was analysed to determine pain induced neuroendocrine stress reaction. To proof the tissue tolerance creatinkinase-(CK) and aspartataminotransferase-(AST) concentration were analysed. One, seven and 14 days after castration the healing process were evaluated by a wound score. Groups I to IV did not show any increase of the serum cortisol level. Contrary one hour after castration the average cortisol concentration of castration groups (V-IX) rose significantly. Cortisol concentration of the medicated castration groups (VI-IX) showed a comparable or even higher cortisol level as the not medicated control group (V). Determination of CK and AST indicated no tissue damage of the application of the local anaesthetics. The administration of local anaesthetics prior to the castration did not have any effect on the wound healing process. The results of this study lead to the conclusion that injection of local anaesthetics show a good tissue tolerance but the call for reduction of the castration pain by presurgical injection of Procaine Hydrochloride or Lidocaine Hydrochloride is not justified.