Table 1 Features of cost, accuracy and data storage of different technologies used to infer ovine heat stress

Temperature loggers (thermistors/thermocouples)

Thermochron iButton (OnSolution, Maxim International)

98 + software and deployment strategy

 ± 0.5 ℃

Data storage, up to 6 months of data in memory, 1–2 year battery life

[15, 51, 53, 85, 124]

DST Micro loggers (StarOddi)

475 + communication box (545), Mercury software (370) + deployment strategy

 ± 0.06 ℃

Automated tympanic probes

FeverTags®, Cow Manager, DoggTag, SenseTag, TekVet

25–40

 ± 0.1 ℃

Data storage,  > 2 year battery life

[124]

Reticulorumen boluses

Smartstock, USA

70 + station (960) and receiver (1790)

 ± 0.2 ℃

Wireless data transmission up to 200 m

[66, 69,70,71, 125, 126]

Infrared Thermography

IRT Thermometer; VTTS-1000 Tympanic Scanner Exergen Corporation®

100

2 ℃ or 0.5%

Manual thermometry

[96, 127]

IRT Camera

1000–4300

 < 0.1 ℃ ± 2%

Contactless, > 3000 m range

[25, 85,86,87, 128,129,130]

Implantable devices

LifeChip® microchips with BIO-THERM® sensor

20–50

 ± 0.5 ℃

Data storage activated through handheld receiver

[15, 66, 86]

GPS collars

UNETracker, WildTrax, EarTrax-AG

2000

5–10 m

Data storage

[26, 115,116,117,118]

Accelerometers

HOBO Pendant G data loggers

195

Up to 99%

Data storage & wireless transmission

[108, 112, 117, 131]

ActiGraphs

290

[109]