Assessment of the Effective Tissue Concentrations of Injectable Lidocaine and a Lidocaine-Impregnated Latex Band for Castration in Calves.

Simple Summary: Castration is commonly performed in young dairy calves and results in pain and discomfort. This study aimed to assess the effective tissue concentrations of the current standard of care for pain mitigation in calves during castration (injectable lidocaine) and to assess the ability of lidocaine-loaded bands (LLBs) to deliver effective concentrations into the scrotal tissue over time. The injectable lidocaine provided effective anesthesia for up to 60 min, highlighting the importance of finding additional strategies to manage long-term pain. A ligation band impregnated with lidocaine could provide a suitable alternative, as it appears to deliver effective lidocaine concentrations starting as early as 2 h following application and lasting at least 28 days after application. Further studies are warranted to compare the use of LLBs to injectable local anesthetics. This study aimed to assess the effective tissue concentrations of the current standard of care for pain mitigation in calves during castration (injectable lidocaine) and to assess the ability of a lidocaine-loaded elastration band (LLB) to deliver effective concentrations into the scrotal tissue over time. This study comprised two different trials: (1) effective concentrations of injectable lidocaine in the scrotal tissue; and (2) the in vivo delivery of effective concentrations of lidocaine from LLBs placed on the calf scrotums. Sensation in the scrotal tissue was assessed by electrocutaneous stimulation. Injectable lidocaine allowed for short-term anesthesia for up to 60 min, highlighting the importance of finding additional strategies to mitigate long-term pain. An elastomeric ligation band impregnated with lidocaine could provide a suitable alternative, as it yielded tissue levels of lidocaine that approached EC50 and exceeded EC95 at 2 and 72 h following application, respectively, and remained above those levels for at least 28 days after application. Further studies are warranted to compare the use of LLBs to injectable local anesthetics. [ABSTRACT FROM AUTHOR]