An investigation of the effects of intratesticular alfaxalone and lidocaine during castration in piglets.

OBJECTIVE: To determine whether intratesticular injection of an alfaxalone-lidocaine combination can induce anesthesia and provide a rapid recovery in piglets undergoing surgical castration.

STUDY DESIGN: Randomized experimental study.

ANIMALS: A group of 30 male piglets, aged 2-10 days, weighing 1.3-4.6 kg.

METHODS: Animals were randomly divided into three equal groups for intratesticular administration of alfaxalone + lidocaine: high dose (group HD; 8 mg kg-1  + 2.5 mg kg-1 ), medium dose (group MD; 6 mg kg-1  + 2 mg kg-1 ) and low dose (group LD; 4 mg kg-1  + 1.5 mg kg-1 ). Induction and recovery times, movement and vocalization were recorded. Pulse rate (PR), oxygen saturation, respiratory rate (fR ), rectal temperature, blood pressure and end-tidal carbon dioxide were recorded until recovery.

RESULTS: Induction time did not differ significantly among groups (p = 0.19); mean time of 2.2, 3.3 and 3.7 minutes for HD, MD and LD, respectively. Recovery time to sternal recumbency was significantly faster in LD compared with HD and MD (p = 0.005). Time to standing was mean 34.1, 31.6 and 29.6 minutes for HD, MD and LD, respectively (p = 0.58). Incidences of movement and vocalization during the castration procedure were decreased in HD and MD compared with LD, but were not statistically different. There were no differences in the physiologic data among the groups except for PR, which decreased in all three groups (p < 0.05), and fR , which increased in MD and LD (p < 0.05).

CONCLUSIONS AND CLINICAL RELEVANCE: The alfaxalone-lidocaine combinations investigated in this study induced deep sedation in all piglets. Physiologic data remained within clinically acceptable ranges, suggesting that this drug combination by intratesticular injection prior to castration in neonatal piglets is well tolerated. The authors recommend the alfaxalone (6 mg kg-1 ) + lidocaine (2 mg kg-1 ) dose.