Equine lameness can cause many horse owners to be extremely worried. Most of the time, it is the main reason why people seek veterinary care. Veterinarians use drugs like intrasynovial or perineural diagnostic analgesia to investigate and localize pain that is causing lameness. Some horses are either needle shy or fractious when it comes to receiving medical care. It hard to make them comply with the veterinarians. Physical constraints may not prove valuable in some cases. Therefore, in such situations, for a safe and precise injection of analgesia, sedation may be required.

Some veterinarians avoid using a2-adrenergic agonist as its effects are still unknown.  Different studies have been conducted previously to find out about the effect of sedation on equine lameness. Xylazine, detomidine hydrochloride and romifidine are among the ones tested by researchers.

The effect of xylazine on equine lameness was tested by many researchers. One study conducted on the collected use of xylazine and butorphanol indicated a significant difference in lameness at 2/5 time points. However, the data relied on a small sample and no statistical data related to the control group and treated group was provided (1). Most of the studies concluded that there was no significant effect of xylazine on equine lameness (2). Moreover, very little evidence is there to prove the impact of xylazine on lameness.

Romifidine showed significant differences in movement asymmetry in head and pelvic region. The results were inconsistent. When used with butorphanol, romifidine did not show any differences in pelvic movement asymmetry.

Detomidine Hydrochloride, when used, did not show any significant differences in forelimb lameness, however the locomotory pattern was altered (3). When used along with butorphanol, the results showed no alteration in head or pelvic movement.

In short, there is very little evidence to show the effect of sedation on equine lameness. The studies conducted on this matter yield contradict each other and show inconsistent results. We still need more work and research on this topic to reach a proper conclusion. Sedation does not seem to cause much of a difference, however, the veterinary surgeons and clinicians should be considerate of the individual physical differences in horses. What may seem okay for one horse may not be suitable for another. Studies conducted on larger sample may help in solving this problem. Till then, it is better to be on the safe side.

Sources:

This article is based upon the research by Termansen & Meehan on “Can sedation be used for equine lameness investigation?” published on 18 Jun 2021.

1.    Da Silva Azevedo, M., De La Côrte, F.D., Brass, K.E., Gallio, M., Pozzobon, R., Lopes, M.A.F. & Lopes, L.F.D. (2015). The Use of Xylazine or Acepromazine Does Not Interfere in the Lameness Evaluation by Inertial Sensors. Journal of Equine Veterinary Science. 35(1), 27–30.
2.    Moorman, V.J., Bass, L. & King, M.R. (2019). Evaluation of the effects of commonly used α2-adrenergic receptor agonists alone and in combination with butorphanol tartrate on objective measurements of lameness in horses. American Journal of Veterinary Research. 80(9), 868–877.
3.    Buchner, H.H., Kübber, P., Zohmann, E. & Peham, C.H. (1999). Sedation and antisedation as tools in equine lameness examination. Equine Veterinary Journal. 30(S30), 227–230.
4.    Rettig, M.J., Leelamankong, P., Pungsri, P. & Lischer, C.J. (2015). Effect of sedation on fore- and hindlimb lameness evaluation using body-mounted inertial sensors. Equine Veterinary Journal. 48(5), 603–607. DOI: https://doi.org/10.1111/evj.12463