Culled red deer – lessons from the carcase

Ken Urquhart BVMS, MRCVSThistle Veterinary Health Centre, Edinburgh&

Iain McKendrick, BSc, PhDBiomathematics and Statistics Scotland,Edinburgh

PublicationsSurvey of permanent wound tracts in the carcases ofculled wild red deer in ScotlandVeterinary Record (2003) 152, 497-501

A study to investigate the prevalence of “head shooting” and the properties of wounds in culled wild Scottish red deer. (In Press)

With thanks to Christian Nissen, Highland Game, Dundee

Control of deer populations in GB

Cull Data 2001/02Deer Species Scotland England & Wales• Red 67,300 ?• Roe 26,200 ?• Sika 3,900 ?• Fallow 1,200 ?• Muntjac & CWD n/a ?

• Culling

•Natural mortality

•Accidental death

Estimated total GB cull - 175,000 deer (British Deer Society)

Role of Licensed Venison Dealers

87% of cull carcases handled by LVD’s

LVD = sampling bottleneck ( )

Sample characteristics 14 sampling days: July-Dec 1173 carcases (943 + 230) 50 deer managers ( ) 200 + marksmen anonymous

Recommended Points of Aim: BDS

Head

High neck

Low neck

Chest

Lethal area 25cm diameter circle

Protection of Deer

• Deer (Scotland) Act 1996– Close seasons– Minimum ballistic requirements

Deer cullers are not legally required to demonstrate competence.

Voluntary standards are set by Peer supervision Code of practice Best practice guidanceFormal training : Deer Stalking Certificates

Aims & Objectives

Specifically• What proportion of deer were head shot and why?• What proportion of animals were neck shot?• What proportion of animals were heart/lung shot?• Number of Permanent Wound Tracts (PWT’s)

Evidence based decision making including

Compliance with Code of Practice and Best Practice Guidance

Content of voluntary training syllabus (Deer Stalking Certificates)

Broadly – to establish base line data on current culling practices

Results

• Head Shooting• 3.5% elective and 3.9% “coup de grace”

• Neck Shooting• 12% hinds and 15% in stags

• Body• 80% of body shot deer were shot through heart/lungs

• Number of wound tracts• > 1 in 12% - 15% of animals• Increases significantly during the rut

“analysis using only the anatomical site of entry/exit wounds will be ….a poor predictor of the outcome ….for culled animals”

• Each time a bullet strikes the animal a PWT is created

• The cessation of the wound tract production (bullet strikes) is likely to coincide with successful culling of the animal

• “Terminal Probability”* – term describes – “the mean probability of each successive wound

tract being the final one generated in a carcase”

Statistical Analysis of Wound Tracts

“a limited but better defined set of data ……an objective measure of the culling event”

Variations in Terminal Probability

• First PWT , outwith the rut 0.88• First PWT, within the rut 0.78• Subsequent PWT’s 0.93

• A lower mean terminal probability is almost certainly associated with a higher mean time from initial wound to death

• Premature to argue for an explicit correlation between (lower) terminal probability and animal welfare– Absence of variables relevant to animal welfare e.g.

• Wound morphology• Sequence in which wound tracts were created• Interval between creation of first and last wound tract

Lessons learned

• Elective head shooting is uncommon (3.5%) and indicates broad compliance with BPG and CoP.

• Neck shooting is common – more research in to physiological effects of neck shooting is required.

• 20% of body shot deer do not have tracts in heart or lungs – current concepts of wound analysis in deer are simplistic compared to human models e.g. Red Cross EXCFVM

• Increased number of wound tracts in stags during the rut warrants further investigation

Dawn

EXCFVM wound classification

E = entry wound: site & size

X = exit wound: site & size

C = presence or absence of a cavity

F = fractures, classed on severity

V = vital structure involved

M = presence of one or more metal fragments in wound

The total amount of energy deposited in the wound by a projectile is a major determinant in the outcome of war wounds in humans.

This fact has perhaps been relatively neglected in studies of culled wild deer and in the educational literature of stalkers where the overriding emphasis remains in recommending shot placement which cause maximal damage to vital (vascular) structures

“In humans, death in < 2 minutes would be considered extremely humane”

Assessing Welfare Standards

• Species specific• Rabbit shot, snared, cage trapped, poisoned (gas)• Fox shot, snared, cage trapped.• Deer shot, enclosure traps

• Method specific• Firearms air weapons, shotguns, rifles• Snares• Poison bait, gas• Traps restraining, killing

• Against Agreed Standards• Catch to kill time

Welfare standards are context dependant