Work

Efficacy of a single central injection of lignocaine at the scrotal neck on the behavioural response of lambs to castration

Year: 2024

Type: article

Abstract: OBJECTIVE: To compare the behavioural responses of lambs to ring castration with or without local anaesthetic administration by single midline injection at the scrotal neck. STUDY DESIGN: Blinded, randomized block design pen study. ANIMALS: A group of 60 male Merino lambs; 6-8 weeks of age; average body weight of 18.5 ± 0.33 (mean ± standard error of the mean) kg at the time of castration. METHODS: Lambs were randomly assigned to three groups of 20: 1) NUMNUTS - lamb placed in a marking cradle and ring castrated with 1.5 mL lignocaine 2%; 2) SHAM - lamb placed in marking cradle and the scrotum manipulated as though an elastrator castration ring were applied; and 3) RING - lamb placed in the marking cradle, ring castration performed using an elastrator. Pain-related behaviours annotated for 1 full minute every 5 minutes post-procedure, from video footage collected for 2 hours post-procedure, according to a defined ethogram. RESULTS: Lignocaine administration led to significant (p < 0.05) reductions in restless behaviour at 5 and 10 minutes in NUMNUTS lambs compared with RING (mean = 0.2 ± 0.4 versus 1.0 ± 0.4, respectively) post castration. A significant (p = 0.01) reduction in foot stamping and kicking behaviour at 5 minutes post castration (mean = 1.5 ± 0.4, for RING versus 0.4 ± 0.4 for NUMNUTS) and significant (p = 0.001) reduction in the sum of all acute pain-related behaviours at 5 minutes post castration. CONCLUSION AND CLINICAL RELEVANCE: A single midline injection of local anaesthetic at the scrotal neck can alleviate the behavioural responses to ring castration in the immediate post-procedure period. However, the duration of effect was limited, which may be a result of the drug we used. Development of a longer-lasting local anaesthetic formulation is imperative to optimize pain mitigation for ring castration.

Source: Veterinary Anaesthesia and Analgesia

DOI: 10.1016/j.vaa.2024.09.006

Authors: Danila Marini, Troy Kalinowski, Alison Small

Institutions: Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food

Language: English

Topic: Veterinary Pharmacology and Anesthesia

Subfield: Small Animals

Field: Veterinary

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,000