Eye Blink Rates and Eyelid Twitches as a Non-Invasive Measure of Stress in the Domestic Horse
Physiological changes provide indices of stress responses, however, behavioural measures may be easier to determine. Spontaneous eye blink rate has potential as a non-invasive indicator of stress. Eyelid movements, along with heart rate (HR) and behaviour, from 33 horses were evaluated over four tre...
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| Format: | Article |
| Language: | English |
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MDPI AG
2019-08-01
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| Series: | Animals |
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| Online Access: | https://www.mdpi.com/2076-2615/9/8/562 |
| _version_ | 1828240042938597376 |
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| author | Katrina Merkies Chloe Ready Leanne Farkas Abigail Hodder |
| author_facet | Katrina Merkies Chloe Ready Leanne Farkas Abigail Hodder |
| author_sort | Katrina Merkies |
| collection | DOAJ |
| description | Physiological changes provide indices of stress responses, however, behavioural measures may be easier to determine. Spontaneous eye blink rate has potential as a non-invasive indicator of stress. Eyelid movements, along with heart rate (HR) and behaviour, from 33 horses were evaluated over four treatments: (1) control—horse in its normal paddock environment; (2) feed restriction—feed was withheld at regular feeding time; (3) separation—horse was removed from visual contact with their paddock mates; and (4) startle test—a ball was suddenly thrown on the ground in front of the horse. HR data was collected every five s throughout each three min test. Eyelid movements and behaviours were retrospectively determined from video recordings. A generalized linear mixed model (GLIMMIX) procedure with Sidak’s multiple comparisons of least squares means demonstrated that both full blinks (16 ± 12<sup>b</sup> vs. 15 ± 15<sup>b</sup> vs. 13 ± 11<sup>b</sup> vs. 26 ± 20<sup>a</sup> full blinks/3 min ± SEM; a,b differ <i>p</i> < 0.006) and half blinks (34 ± 15<sup>ab</sup> vs. 27 ± 14<sup>bc</sup> vs. 25 ± 13<sup>c</sup> vs. 42 ± 22<sup>a</sup> half blinks/3 min ± SEM; a,b,c differ <i>p</i> < 0.0001) decreased during feed restriction, separation and the startle test compared to the control, respectively. Eyelid twitches occurred more frequently in feed restriction (<i>p</i> < 0.0001) along with an increased HR (<i>p</i> < 0.0001). This study demonstrates that spontaneous blink rate decreases while eyelid twitches increase when the horse experiences a stressful situation. |
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| issn | 2076-2615 |
| language | English |
| last_indexed | 2024-04-12T21:33:32Z |
| publishDate | 2019-08-01 |
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| series | Animals |
| spelling | doaj.art-4dba0c8cab8f40508e6b811643aac74f2022-12-22T03:15:58ZengMDPI AGAnimals2076-26152019-08-019856210.3390/ani9080562ani9080562Eye Blink Rates and Eyelid Twitches as a Non-Invasive Measure of Stress in the Domestic HorseKatrina Merkies0Chloe Ready1Leanne Farkas2Abigail Hodder3Department of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, CanadaDepartment of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, CanadaDepartment of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, CanadaDepartment of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, CanadaPhysiological changes provide indices of stress responses, however, behavioural measures may be easier to determine. Spontaneous eye blink rate has potential as a non-invasive indicator of stress. Eyelid movements, along with heart rate (HR) and behaviour, from 33 horses were evaluated over four treatments: (1) control—horse in its normal paddock environment; (2) feed restriction—feed was withheld at regular feeding time; (3) separation—horse was removed from visual contact with their paddock mates; and (4) startle test—a ball was suddenly thrown on the ground in front of the horse. HR data was collected every five s throughout each three min test. Eyelid movements and behaviours were retrospectively determined from video recordings. A generalized linear mixed model (GLIMMIX) procedure with Sidak’s multiple comparisons of least squares means demonstrated that both full blinks (16 ± 12<sup>b</sup> vs. 15 ± 15<sup>b</sup> vs. 13 ± 11<sup>b</sup> vs. 26 ± 20<sup>a</sup> full blinks/3 min ± SEM; a,b differ <i>p</i> < 0.006) and half blinks (34 ± 15<sup>ab</sup> vs. 27 ± 14<sup>bc</sup> vs. 25 ± 13<sup>c</sup> vs. 42 ± 22<sup>a</sup> half blinks/3 min ± SEM; a,b,c differ <i>p</i> < 0.0001) decreased during feed restriction, separation and the startle test compared to the control, respectively. Eyelid twitches occurred more frequently in feed restriction (<i>p</i> < 0.0001) along with an increased HR (<i>p</i> < 0.0001). This study demonstrates that spontaneous blink rate decreases while eyelid twitches increase when the horse experiences a stressful situation.https://www.mdpi.com/2076-2615/9/8/562spontaneous blink rateeyelid twitchesstresshorsebehaviourwelfare |
| spellingShingle | Katrina Merkies Chloe Ready Leanne Farkas Abigail Hodder Eye Blink Rates and Eyelid Twitches as a Non-Invasive Measure of Stress in the Domestic Horse Animals spontaneous blink rate eyelid twitches stress horse behaviour welfare |
| title | Eye Blink Rates and Eyelid Twitches as a Non-Invasive Measure of Stress in the Domestic Horse |
| title_full | Eye Blink Rates and Eyelid Twitches as a Non-Invasive Measure of Stress in the Domestic Horse |
| title_fullStr | Eye Blink Rates and Eyelid Twitches as a Non-Invasive Measure of Stress in the Domestic Horse |
| title_full_unstemmed | Eye Blink Rates and Eyelid Twitches as a Non-Invasive Measure of Stress in the Domestic Horse |
| title_short | Eye Blink Rates and Eyelid Twitches as a Non-Invasive Measure of Stress in the Domestic Horse |
| title_sort | eye blink rates and eyelid twitches as a non invasive measure of stress in the domestic horse |
| topic | spontaneous blink rate eyelid twitches stress horse behaviour welfare |
| url | https://www.mdpi.com/2076-2615/9/8/562 |
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