Agriculture and Agriculture etAgri-Food Canada Agroalimentaire Canada

Infrared thermography and heart rate

variability for non-invasive assessment of

animal welfare.

ANZCCART 2008

Mairi Stewart

Jim Webster, Kevin Stafford & Allan Schaefer

•Measures emitted radiated heat (represents 40-60% of heat loss from an animal)

•Non-invasive – images collected from a distance

•Can detect changes in heat loss during stress (due to regulation of peripheral blood flow)

What is infrared thermography ?

Photo from U.S. Department of Defence Polygraph

You can't hide your lying eyes…

Approach

Measure responses to routine husbandry procedures used on-farm (eg handling, disbudding)

38

38.2

38.4

38.6

38.8

39

39.2

-120 -60 0 60 120 180

Time (sec)

Eye

tem

pera

ture

(o

C)fright

Autonomic Nervous System

Restores energy reserves

Mobilises energy reserves

Parasympathetic Sympathetic

-vasodilation - vasoconstriction

- secretion of catecholamines

What is heart rate variability?• Non-invasive

• Cardiac interbeat (RR) interval = time between successive R waves

• Provides more accurate measure of stress than heart rate

• Allows measurement of sympathetic and parasympathetic responses

Components of the ECG

0.0

1.0

2.0

3.0

4.0

5.0

6.0

Control Disbud only Local only Disbud + local

Ch

an

ge

in L

F/H

F r

atio

Heart rate variability - disbudding- Sympathetic Nervous System Indicator

***

36.6

37

37.4

37.8

38.2

-25 -20 -15 -10 -5 0 5 10 15

Time (min)

Ma

x e

ye

te

mp

era

ture

(oC

)

Control

LA only

Disbud only

LA + Disbud

Eye temperature - disbudding

******

*

baseline LA Disbud

vasoconstrictionTime (min)

Adrenaline challenge – eye temperature

37.7

37.8

37.9

38

38.1

38.2

-15 -10 -5 0 5 10 15

Time (min)

Eye

tem

pera

ture

(oC

)

Epinephrine

Saline

infusion

Summary

• Eye temperature dropped in response to:• fright • painful procedure• adrenaline

• Evidence that the drop in eye temperature is mediated by sympathetic activity

Conclusions1. A combination of eye temperature and HRV is a

useful non-invasive assessment of autonomic activity.

2. May be an alternative to invasive methods currently used to assess farm animal welfare.

Questions?