Equine Euthanasia

Reasons for euthanasia (6)

1. Prevent pain and suffering

2. Degenerative conditions with detrimental effects on quality of life

3. Geriatric

4. Safety (unmanageable behaviour)

5. Loss of use

6. Convenience

What’re some examples of ‘incurable’ diseases or injury that would warrant humane euthanasia? (there’s up to 11)

• Surgical colic that O can’t afford/won’t elect surgery

• Colic with evidence of GI perforation → septic peritonitis & septic shock

• Bone fracture/soft tissue injury that’s irreparable

• Severe laminitis not stabilising with therapy and poor long-term prognosis

• Septic synovial structure (adult or foal) where referral for appropriate care is not elected by the owner

• Non-reversible/Non-responsive to therapy acute or chronic renal failure

• CHF

• Severe equine asthma refractory to therapy

• Severe pleuropneumonia or colitis with SIRS/endotoxemia/sepsis that deteriorate despite therapy/O can’t afford intensive care

• Severe neoplasia/disease which affects QoL

• Congenital defects that are non-viable with life

What’re some examples of conditions/diseases where a horse may be deemed dangerous or hazard to humans or itself? (3)

• Severe neurological disease (forebrain i.e. seizure or behavioural changes, spinal i.e. ataxia/recumbency)

• Severe cardiac disease where behaviour is unpredictable or unsafe to ride the horse and cannot be treated

• Behaviour that is dangerous/wild and does not respond/improve with training

What’re some important criteria when considering human euthanasia in geriatric patients?

• Are they still paddock sound/have good quality of life: interest in eating/drinking, ambulating comfortably to access food/water; maintaining bodyweight

• Musculoskeletal disease that is debilitating causing chronic pain and inability to ambulate to eat/drink (e.g. chronic OA, navicular disease, degenerative suspensory ligament disease, chronic laminitis

• PPID that is end-stage and affecting quality of life or O elected not to treat

• Dental dz/loss of significant number of functional clinical crown that eating hay/pasture is not possible anymore and owner’s cannot afford or have time to feed appropriate mash/high fiber hard-feed alternatives, leading to malnutrition and weight loss

• Unexplained weight loss and ability to maintain healthy condition and owner can’t/won’t elect to investigate the underlying cause with additional diagnostics or referral

Consent for euthanasia (4)

• Consent for euthanasia should be given by owner.

• Written (e.g. a signed form) ideally or verbal

• Check if the horse is insured

• If yes, ensure the appropriate paperwork and documentation is completed.

For welfare cases where consent from the owner is not given, you should seek a second professional opinion: e.g (3)

• another veterinarian

• SPCA

• police

Location and planning of euthanasia (4)

• Safety is a priority - cannot always control the way they go down, have an experienced handler if possible and restraint

• Location - Large, flat area clear from objects etc so the horse can go down safely, accessible for removal

• Discuss options for the body - PM, cremation, body disposal, hounds, burial

• If burial possible, ensure it’s client’s land or permission to do so from the land owner, that the hole is large and deep enough and that the site is away from waterways or inaccessible to other animals

Acceptable methods of humane euthanasia (4)

• Overdose of intravenous barbiturate (pentobarbital sodium solution).

• Penetrating captive bolt.

• Gunshot.

• Others under GA: injecting potassium chloride, magnesium chloride, magnesium sulfate IV, intra-thecal lignocaine, exsanguination

Lethal Injection - IV Barbiturate

2 advantages

drug used (extra points if you know the dose rate)

• Pain free and least traumatic

• Most common use is pentobarb 500 mg/ml, around 50ml per 200kg, cheap, however it is very thick

Gunshot

Steps: (3)

• Restrain

• Pre-medicate with sedation

• Fire in the X between eyes and ear tips with the weapon fired close to or on skull

Captive bolt

Injecting potassium chloride

Not common, requires GA

Premed with xylazine followed by ketamine (GA) and then inject to create cardiac arrest

Intra-thecal 2% lignocaine under GA

Premed with xylazine followed by ketamine, clip midline over the atlanto-occipital joint, flex the head, insert a 6 inch 18 guage needle directed toward the lower jaw, administer 60ml of 2% lignocaine

Three important points about exsanguination (3)

• Needs to be under GA

• can cut throat or cut aorta per rectum

• This technique is rarely used and usually only in special circumstances

Prepare owner for administering of lethal injection (4)

It is important to inform the owner of what to expect:

• horse sedated prior to overdose of anaesthetic

• it is not painful and the horse is unconscious as it goes down,

• can be hard to watch

• do they want to be there?

Patient preparation for lethal injection (5)

• Pre-med with xylazine IV (or other alpha-2 agonist)

• Wait 5 mins for full sedation effect

• Safe halter and lead rope

• Have someone comfortable with holding horse around to help while you administer the drug

• In some cases you may not have time to sedate

List the steps for lethal injection (8)

• 14G temporary IV catheter (or needle if you’re brave)

• Add a short extension-set, makes access much easier.

• Draw up the recommended dose, wear gloves, have an extra bottle at hand

• Check level of sedation, attach first syringe to extension set, bolus the drug (don't let go of the hub), and do the second syringe quickly

• Clamp or Tie knot in extension kit to avoid pentobarb and blood leaking out

• Take the horse's head from the person holding

• Keep head in neutral position and the horse will fall

• Check the horse is dead

How much pentobard to draw up

Usually draw up 100-120mL (2 x 50-60ml syringes) for average size horse (~500kg), 10mL for a neonatal foal.

Once the horse is recumbent, what must you check to confirm the horse is dead before leaving the property? (3)

• Loss of heartbeat and pulse

• No signs of life, agonal gasps and spontaneous movement have all ceased

• Loss of corneal reflex - this is the last reflex they will loose (check palpebral reflex first)

When would you decide to administer more pentobarbital?

• Start breathing

• Stead heart beat which is not decreasing over time

• Strong palpebral reflex or nystagmus

• Still moving or any other indication the animal is not dead