Discussion

This presentation aims to provide an overview of the challenges that face clinicians when dealing with euthanasia at competition events. Examples of the common pitfalls associated with the use of Somulose and a free bullet will be given together with ways in which these problems can be avoided or minimised. Illustrations, including video clips, will highlight the particular idiosyncrasies of each method.

Introduction:
Providing veterinary services at a competition event provides a challenging environment to work in, particularly when faced with a horse that requires euthanasia. However, the stress can be minimised with good preparation and planning.

Preparation:
The facilities and the access points to all parts of course should ideally be checked personally prior to the event as should the equipment, drugs, firearms and ammunition. A suitable, secure bag that can safely store a stethoscope and the required equipment and provides easy rapid access during an emergency is essential.

Somulose:
Ensure that a suitable number of bottles are available for the event. The wrappings from the box should be removed prior to the event to save valuable time in the event of an emergency and prevent the embarrassment of fumbling with cellophane wrapping during a stressful situation. It also gives the opportunity to check the clarity of the Somulose solution. It should be a clear viscous that is slightly straw coloured. Bottles containing cloudy liquid should be returned to the manufacturer and not used.

Firearm:
Ensure that the firearm is well maintained and of a suitable calibre (>0.32) with a sound moderator attached. A trigger lock can be fitted to increase security during transport. Adequate soft nosed ammunition should be kept separate from the firearm. It is essential to remember that a firearm can only be used by someone with a current Firearm Certificate on which the specific Firearms and Sound Moderators details are included.

Factors to be considered prior to euthanasia:
On the day wear easily identifiable clothing, such as a tabard or an armband. People will look to the veterinary surgeon for leadership; therefore, a calm professional approach is required together with excellent clinical and communication skills.

Decisions should be made on clinical grounds and not on the perceived value of the horse. Adequate sedation is essential to assess a fractious horse thoroughly, however, some spinal fractures and pelvic fracture cases can be difficult to sedate. A preloaded syringe of an alpha2 agonist (not xylazine) and Butorphanol saves time and a dose rate of 1 ml of each is often required when a horse is injured during competition. Very occasionally it is not possible to get close enough to a distressed animal to give intravenous sedation and intramuscular administration is required either via a standard syringe or a remote injection device (Masterject)1.

Proportional and reasonable decision making is required. In all but the most obvious and extreme incidents a second opinion should be sought if at all possible.

A thorough knowledge of the BEVA guidelines for the destruction of horses under all risks mortality insurance policy is required so that authoritative advice can be given to clients. Many insurance companies will also require a post mortem examination to comply with the terms and conditions of the policy.

If in doubt, sedate, wait and re-evaluate. Get a second opinion and take advantage of further diagnostic modalities if available. Immobilisation of injured leg via a splint, dressing or cast provides excellent analgesia and it will buy time to allow considered decision making.

Informed consent:
Informed consent from owner, trainer or representative is of primary importance and written confirmation of this is ideal. Preprepared consent forms are good, however, this procedure should not become mechanistic; a form pushed under the nose of a distressed client does not constitute informed consent.

Euthanasia:
Ideally it should be carried out behind screens, however, in high winds staff may be unable to secure them adequately or the flapping may spook the horse. In these situations vehicles can be used to screen the horse from spectators.

It is essential that the vet ensures the horse is dead before leaving the site. Ten minutes will usually provide a safe margin. Positive identification is required either ante mortem or post mortem. A brief written description and confirmation of the microchip number, if present, is ideal.

Somulose (Dechra)2:
Somulose is a combination of Secobarbital sodium (quinalbarbitone) and Cinchocaine hydrochloride. Secopbarbitone has a rapid onset of action, which profoundly depresses the central nervous system, including the respiratory centres. Cinchocaine has marked cardiotoxic effects at high doses. It is a potent drug which is highly toxic to man and therefore has significant health and safety implications.

The data sheet strongly recommends the preplacement of a
14 gauge catheter, although many practitioners will inject off a
16 gauge needle. Whichever method is used it is critical that the full dose is injected over 10 - 15 s. Adequate sedation is, in the authors opinion, essential although xylazine should be avoided as unacceptable violent muscular activity has been reported following its use (Knottenbelt et al. 1994),. The average time from start of injection to collapse is 34 s, the difference between sedated and unsedated is 8 s (Knottenbelt et al. 1994).
Potential complications may arise for a number of reasons and include: inadequate sedation, sedation with xylazine, use of cloudy Somulose, perivascular injection, use in horses in circulatory collapse, incorrect injection speed, insufficient dose, and accidental self administration.

Firearm:
The advantages of this technique are that it is rapid, very effective, easy (if experienced) and cheap. Gun placement at the correct

location and in the required direction will ensure the shot penetrates the brain towards foramen magnum. The result is immediate and dramatic. Some reflex movement of the limbs are often seen once the horse is on the ground. The amount of blood is variable; however, placing the head in a plastic bag can reduce visual impact.

Potential complications may arise for a number of reasons and include: 1) Incorrect placement of gun. This may be due to inexperience, the attachment of the sound moderator, movement of horse just prior to trigger release, the head being in unusual or awkward position. Minor misplacement may result in excessive movement and bleeding. Major misplacement may require a second shot or lethal injection; 2) Gun malfunctions. These are normally a reflection of inadequate maintenance and include an inability to remove a spent round, gun jamming shut or a trigger malfunction;
3) Personnel injury due to the free bullet or falling horse.