Consistent behavioural responses to heatwaves provide body condition benefits in rangeland sheep

Leu, Stephan T.; Quiring, Katrin; Leggett, Keith E. A.; Griffith, Simon C.

doi:10.1016/j.applanim.2020.105204

Cited by 10 publications

(29 citation statements)

References 46 publications

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“…We followed the same data processing procedure as in Leu et al (2021). In brief, spatial outliers were removed from the raw GPS data using three methods, (1) all locations that used less than 3 satellites or were clearly outside the fenced study area; (2) locations that an individual could not have moved to at a maximal movement speed (180 m per 2 min i.e.…”

Section: Gps Data Processingmentioning

confidence: 99%

“…Heat stress also elicits changes in behaviour to avoid hyperthermia. Individuals can limit or change their activity patterns when ambient conditions are particularly challenging (Bourgoin et al 2011; Hetem et al 2012; Fuller et al 2016; Leu et al 2021). Similarly, animals can avoid microclimates that are hot and in direct sun and shift their space use to favour shaded areas (Hetem et al 2012; Leu et al 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Individuals can limit or change their activity patterns when ambient conditions are particularly challenging (Bourgoin et al 2011; Hetem et al 2012; Fuller et al 2016; Leu et al 2021). Similarly, animals can avoid microclimates that are hot and in direct sun and shift their space use to favour shaded areas (Hetem et al 2012; Leu et al 2021). Reduced food intake to decrease metabolic heat production, increased drinking frequency, and increased standing time to increase surface area for heat loss by convection (Galán et al 2018) have also been recorded during hot conditions.…”

Section: Introductionmentioning

confidence: 99%

“…During heat stress conditions sheep spend time in the shade as a behavioural response to support physiological thermoregulation (Leu et al 2021). Sheep also spend more time at watering points to avoid dehydration, and activity levels are substantially lower compared to more typical conditions (Leu et al 2021). Sheep that were kept under tree shade showed fewer heat stress related behaviours and shade use behaviour reduced radiant heat load (De et al 2020).…”

Section: Introductionmentioning

confidence: 99%

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Heat stress conditions affect the social network structure of free-ranging sheep

Borthwick

Quiring

Griffith

et al. 2023

Preprint

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Extreme weather conditions, like heatwave events, are becoming more frequent with climate change. Animals often modify their behaviour to cope with environmental changes and extremes. If the environmental conditions influence the trade-off between an individual's social propensity and optimal thermoregulation through shade use for instance, then divergent social decisions may be made. Hence, such behavioural changes have the potential to influence an individual's position in its social network, and the social network structure as a whole. We investigated whether heat stress conditions (quantified through the Temperature Humidity Index) and the resulting use of shaded areas, influences the social network structure and an individual's position in it. We studied this in free-ranging sheep in the arid zone of Australia, GPS-tracking all 48 individuals in a flock. When heat stress conditions worsened, individuals spent more time in the shade and the network was more connected (higher density) and less modular. Furthermore, an individual's social connectivity scaled with its shade use behaviour. Interestingly, individuals with intermediate shade use were most strongly connected (degree, strength, betweeness), indicating their importance for the connectivity of the social network during heat stress conditions. Our study shows that heat stress conditions, which are predicted to increase in severity and frequency due to climate change, influence the resource use within the ecological environment. This has flow on effects for the animal's social environment through the changed social network structure.

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Section: Gps Data Processingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Heat stress conditions affect the social network structure of free-ranging sheep

Borthwick

Quiring

Griffith

et al. 2023

Preprint

Self Cite

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“…Heat stress often occurs when the effective environmental temperature exceeds the upper critical temperature of a sheep (25 to 31 °C) [2], resulting in an imbalance between heat production within the body and its dissipation. Biologically, animals have the ability to minimise the negative effects of hot conditions by invoking physiological mechanisms [3], such as an increase in respiration rate and body temperature, as well as by adjusting their activity and feeding patterns to avoid hot periods of the day or increase the use of shaded areas [4]. An increase in core temperature is one of the primary physiological indicators and has been used to evaluate the heat stress response in sheep [5].…”

Section: Introductionmentioning

confidence: 99%

Validation of indwelling vaginal sensor to monitor body temperature in ewes

et al. 2022

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Remote-sensing technology facilitates longitudinal collection of body temperature during periods of hot or cold environmental stress without human interference, producing high-frequency measurements whilst reducing labour and stress to the animal. A pilot study was conducted to validate an improved, minimally invasive method for the continual measurement of vaginal temperature (VT) in female sheep. A silicon mould of a modified controlled internal drug release (CIDR) device (Zoetis Animal Health, Parsippany), was manufactured to securely house a temperature logger (Micro-T 16-bit; Star Oddi, Iceland) and allow direct contact at the collection site. These temperature-sensing CIDR devices were validated against manual rectal temperature (RT) measurements collected from 15 mature, non-pregnant, non-lactating Merino ewes. Rectal temperature was measured from each individual, six times per day in 2-h intervals for 14 consecutive days. The simultaneous measures of VT and RT did not differ significantly within each ewe (P > 0.05) and demonstrated a moderate linear relationship (R2 = 0.62, P < 0.05). The mean (± SEM) difference between RT and VT was small (0.010 ± 0.004 °C), with a 95% confidence interval of − 0.26 to 0.29 °C. Additionally, the coefficient of variation was lower on average for VT (0.49%) compared to RT (0.59%). Differences among paired readings were likely due to interval variation as well as penetration depth, air influx and faecal temperature when collecting RT. The initial silicone manufacturing costs were high (2200 AUD), with each unit costing 1.25 (AUD) thereafter; however, the temperature-sensing CIDR device was an effective and efficient research tool for the remote monitoring of body temperature. While further validation of these devices within extensive grazing environments is warranted, the collection and analysis of longitudinal physiological data from ewes has the potential to improve a variety of management aspects related to extensively grazed ewes maintained and joined in harsh conditions.

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Heat stress conditions affect the social network structure of free‐ranging sheep

Borthwick,

Quiring,

Griffith

et al. 2024

Ecology and Evolution

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Extreme weather conditions, like heatwave events, are becoming more frequent with climate change. Animals often modify their behaviour to cope with environmental changes and extremes. During heat stress conditions, individuals change their spatial behaviour and increase the use of shaded areas to assist with thermoregulation. Here, we suggest that for social species, these behavioural changes and ambient conditions have the potential to influence an individual's position in its social network, and the social network structure as a whole. We investigated whether heat stress conditions (quantified through the temperature humidity index) and the resulting use of shaded areas, influence the social network structure and an individual's connectivity in it. We studied this in free‐ranging sheep in the arid zone of Australia, GPS‐tracking all 48 individuals in a flock. When heat stress conditions worsened, individuals spent more time in the shade and the network was more connected (higher density) and less structured (lower modularity). Furthermore, we then identified the behavioural change that drove the altered network structure and showed that an individual's shade use behaviour affected its social connectivity. Interestingly, individuals with intermediate shade use were most strongly connected (degree, strength, betweenness), indicating their importance for the connectivity of the social network during heat stress conditions. Heat stress conditions, which are predicted to increase in severity and frequency due to climate change, influence resource use within the ecological environment. Importantly, our study shows that these heat stress conditions also affect the animal's social environment through the changed social network structure. Ultimately, this could have further flow on effects for social foraging and individual health since social structure drives information and disease transmission.

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Consistent behavioural responses to heatwaves provide body condition benefits in rangeland sheep

Cited by 10 publications

References 46 publications

Heat stress conditions affect the social network structure of free-ranging sheep

Heat stress conditions affect the social network structure of free-ranging sheep

Validation of indwelling vaginal sensor to monitor body temperature in ewes

Heat stress conditions affect the social network structure of free‐ranging sheep

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