How to Sedate and Anesthetize the “Untouchable” Horse

HOW-TO SESSION: FIELD ANESTHESIA AND PAIN MANAGEMENT

Stacey Tarr, DVM

1. Introduction the gentle horse to him. The presence of a quiet Most practitioners have been presented, at some animal tends to provide a calming influence. By time or another, with an animal that has never been placing the intractable horse between a wall or very haltered or halter-broke and is in need of some type sturdy fence and the gentle horse, I am usually able of veterinary care. This is a common occurrence in to get a needle into the jugular vein. The size of the my area, and I have several ways that I deal with needle to be used is often related to volume of med- these types of horses. I will discuss methods on ication to be administered and is an individual pref- how I do this further, keeping in mind that the erence. I have no particular needle preference in safety of both the horse and the human handler is this setting and often use whatever will get the job always the first priority when dealing with this type done safely and quickly at the time. It has been my of animal. There are a few variations in normal experience that these animals react less to this ap- drug doses that I use on intractable horses, and proach than to any attempt at petting or rubbing. these will be discussed. Keep in mind that most I try to get the needle placed with as little direct are based on trial and error and have served me well contact with the horse as possible. In most scenar- in my experience.1–4 ios, with a little time, a jugular stick is possible. In some cases, however, I may have to use an intra- 2. Methods muscular injection. When attempting to treat intractable animals that It is very important that the horse used is quiet require sedation, the placement of a needle in the and accustomed to being around other horses. This jugular vein can be extremely difficult. I use sev- is not a good time to work with a young colt as an aid eral methods to accomplish this. to sedate an intractable horse. Oftentimes, sedation is accomplished with no halter on the intracta- First Method ble horse, and a broke, quiet horse is an invaluable The use of a broke, quiet, or gentle horse can be assistant. helpful when working on another horse that has not Once I have sedated the problem horse, I will still been halter-broke or handled. I put the problem use the broke horse as a “blocker” to halter the horse horse in a sturdy stall or run and begin to introduce that I am working on. This technique will protect

NOTES

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Table 1. Drugs and Dosages for Sedation

Drug IV Dose (mg/kg) IV Dose/450 kg IM Dose (mg/kg) IM Dose/450 kg

Xylazine 2–3 900–1500 (9–15 mL) 3–5 1200–2000 (12–20 mL) Detomidine 0.03–0.04 15–20 (1.5–2 mL) 0.04–0.06 20–40 (2–4 mL) Butorphanol 0.01–0.04 5–20 (0.5–2 mL) 0.02–0.05 5–25 (0.5–2.5 mL)

Note: Doses are considerably greater than those used in horses that are accustomed to interaction with humans.

from any sudden breaks in sedation until you can start to go down. It is very important not to let better control the animal with a halter and lead them out of the chute too early because you probably rope. Once the horse is haltered and sedated, I can will end up chasing a horse that is overriding the usually work with them. Occasionally, I will use a drugs given. saddled horse so that I can dally the lead rope of the Again, with true “bucking horses,” very few problem horse to the saddle horn to help control the procedures can be performed without general un-broke animal. If this is the case, be sure that anesthesia. the saddle horse is accustomed to having something large dallied on the saddle horn. Drugs and Dosages Drugs and dosages for sedation are given in Table 1. Second Method Drugs and dosages for anesthesia are as follows. In some cases, the problem horse must be roped. I only attempt this if I have a very sturdy stall or Ketamine: 2 to 4 mg/kg IV (150–200 mg/45 kg small pen and enough available time to complete the (100 lb) process. I prefer not to rope these horses, because Diazepam: 0.1 mg/kg IV (40 mg (8 mL)/450 kg this is a trainer’s area more than it is mine. Often (1000 lb) horse—maximum, 8 mL during this scenario, horses become so excited that they will override the effects of drugs quite easily. Guaifenesin Recipes (Triple Drip) Still, in some cases, I have no other options and am often able to get a needle in the jugular vein this For adult horses, add 5 to 10 mL of xylazine (100 mg/ way. Again, a good saddle horse can sometimes be mL) and 15 to 20 mL of ketamine (100 mg/mL) to 1 invaluable as a stabilizing and calming influence. liter of 5% guaifenesin. For young foals, add 5 mL of xylazine (100 mg/mL) Third Method and 10 mL of ketamine (100 mg/mL) to 1 liter of 5% The third method I will discuss is an approach that guaifenesin. I use mainly with bucking horses. In the tradi- Yearlings and mature horses require higher doses tional sense, true “bucking horses” are by and large of xylazine and ketamine. unable to be handled without proper chutes and alleys. The majority of these types of horses are 3. Discussion owned by rodeo stock contractors, and in most in- These are by no means the only ways to work with stances, the equipment and help necessary to work an intractable horse; however, they represent what on them is available. With the proper equipment has worked best thus far in my experience. I try, and help, the job can be done safely and in a timely, first and foremost, not to get myself or anyone else efficient manner. injured and to be as safe as possible with the horses. Bucking chutes are a must and extremely benefi- You must be able to adapt the doses of the drugs cial when castrating or working on the distal limbs from case to case—the more intractable animals re- of bucking horses. Unless dealing with a head or quire much larger doses of drugs to achieve the same dorsal body wound, anesthesia will be required. result as a quiet animal. The most intractable These horses do benefit from a blindfold on occasion. horses will also require close monitoring of sedation A good, strong halter and lead rope are a necessary or anesthesia levels. requirement. Keep in mind that these animals are highly reac- Most bucking horses are accustomed to being hal- tive to external noise and stimuli. Be quiet and get tered in the chutes, and once haltered, they can be the job done. These animals wake up quickly. restrained and allow a needle to be placed in the It is best to leave the eyes covered and let the horse jugular vein. The chutes allow you to administer lay as long as possible in an area that is safe for it to the sedation and induction drugs, but be careful not recover. I often remove the halter and lead rope to get your head or arms in a position to be injured. before the horse wakes up because any type of hu- Once sedation and induction have been achieved, man assistance during recovery usually makes the you can then open the chute gate as soon as they situation worse.

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References 3. Hubbell JAE, Hinchcliff KW, Schmall LM, et al. Cardio- 1. Greene SA, Thurmon JC, Tranquilli WJ, et al. Cardiopul- respiratory and metabolic effects of xylazine, detomidine, monary effects of continuous intravenous infusion of guaife- and a combination of xylazine and acepromazine adminis- nesin, ketamine, and xylazine in ponies. Am J Vet Res 1986; tered after exercise in horses. Am J Vet Res 1999;60:1271– 47:2364–2367. 1279. 2. Wagner AE, Mama KR, Contino EK, et al. Evaluation of 4. Hubbell JAE, Hinchcliff KW, Schmall LM, et al. Sedative sedation and analgesia in standing horses after administra- administration to horses immediately after maximal exercise: tion of xylazine, butorphanol and subanesthetic doses of ket- determination of drug and dose, in Proceedings. Am Assoc amine. J Am Vet Med Assoc 2011;238:1629–1633. Equine Pract 1997;43:279–282.

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