Thermoregulatory response to outdoor heat stress of hair sheep females at different physiological state

Macías‐Cruz, Ulises; Correa‐Calderón, Abelardo; Mellado, Miguel; Meza-Herrera, César A.; Aréchiga, C. F.; Avendaño‐Reyes, Leonel

doi:10.1007/s00484-018-1615-2

Cited by 13 publications

(8 citation statements)

References 32 publications

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“…In addition, under the condition of the present study, the significant increase in RT was observed in the EG over the CG; this increase is due to the lack of the body's ability to maintain its thermal equilibrium [6]. Macías et al [12] reported that in non-lactating ewes the differences in RT increase over the course of the d, being smaller in the morning and greater in the afternoon during the summer season. Similarly, in the study by Silva et al [26], significant effects of higher RT values were observed in the hottest h of the d which is consistent with the present values observed in both groups during the afternoon.…”

Section: Table II Differences In Meteorological Parameters Between Morning and Afternoon In Both Groupsmentioning

confidence: 40%

“…In the present study it was observed that the increase in the ET and ITH during morning and afternoon caused the ewes to present significant increase in the RF, which shows the importance of RF as a mechanism of heat loss in small ruminants. Macías et al [12] reported that in non-lactating females differences in RF increased during the warmer h during the d due to the activation of mechanisms for heat loss.…”

Section: Table II Differences In Meteorological Parameters Between Morning and Afternoon In Both Groupsmentioning

confidence: 99%

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Physiological response to thermal stress in hair-sheep ewes during subtropical summer

et al. 2021

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With the aim to assess the effect of short-term thermal stress on physiological traits of ewes an experiment was designed. Fourteen hair sheep ewes were selected during early reproductive management and randomly segregated in two groups. Control group (CG) with indoor conditions, and an experimental group (EG) under continuous outdoor conditions without shadow accessing during 14 days (d). Respiratory frequency (RF), rectal temperature (RT) and infrared image temperatures were estimated. Traits were measured for 8 d twice a d (9:00 am and 15:00 pm). Environmental temperature and humidity were monitored, and temperature and humidity index was estimated. All physiological and environmental traits showed significantly variation by group and time of measurement (P < 0.001). RT and RF were significantly higher for EG and during pm measurements. Environmental conditions indicated thermal stress conditions for outdoor EG during the afternoon was related ultimately with respiratory mechanism as the main indicator of continuous thermal stress. Head infrared image temperature was a good predictor of body temperature.

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Section: Table II Differences In Meteorological Parameters Between Morning and Afternoon In Both Groupsmentioning

confidence: 40%

Section: Table II Differences In Meteorological Parameters Between Morning and Afternoon In Both Groupsmentioning

confidence: 99%

Physiological response to thermal stress in hair-sheep ewes during subtropical summer

et al. 2021

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“…Esto no significa que no haya razas de lana tolerantes al EC en otros países; en Australia, la raza Merino muestra gran capacidad de adaptación a regiones cálidas (1) . La respuesta termorregulatoria de los ovinos al EC también varía con el sexo, y dentro del sexo con la edad, estado fisiológico y actividad reproductiva (5,21) . Mientras que los efectos negativos de EC son más notorios en crías y ovejas gestantes y lactando (21,22) , en carneros parecen ser menos perceptibles ya que su producción de calor metabólico es bajo comparado con las ovejas, y más cuando se encuentran en descanso reproductivo (1) .…”

Section: Estrés Por Calor Y La Producción Ovinaunclassified

Termorregulación y respuestas reproductivas de carneros bajo estrés por calor. Revisión

Sierra¹,

Avendaño‐Reyes

Rivera

et al. 2021

Rev. Mex. Cienc. Pecu.

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Las temperaturas elevadas registradas durante la época de verano en las regiones cálidas comprometen la capacidad reproductiva de los animales domésticos. En carneros, el estrés por calor (EC) causa en el organismo una serie de ajustes fisiológicos, metabólicos, endocrinos y moleculares con el objeto de mantener normotermia y sobrevivir; sin embargo, varios de estos cambios se asocian negativamente con su fertilidad, principalmente los endocrinos. El EC en carneros provoca una disminución en las concentraciones sanguíneas de testosterona a través de diferentes mecanismos, y esto se refleja negativamente en el proceso de espermatogénesis y en la conducta sexual. En consecuencia, los carneros estresados por calor presentan baja calidad seminal y apetito sexual; a nivel de espermatozoides se ha observado daño estructural y en el ADN. Dada esta situación, se recomienda el uso de estrategias de mitigación del EC durante el verano en las explotaciones ovinas de regiones cálidas, tales como el uso de sombras en corrales, la administración de antioxidantes o modificaciones en la alimentación. Por lo tanto, el objetivo de este documento es revisar el conocimiento actual en relación al efecto del EC sobre la capacidad de termorregulación y reproductiva de los carneros, así como la aplicación de estrategias para su mitigación.

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“…For example, changes in diet composition has the potential to reduce the amount of heat released during feed fermentation and improve heat tolerance [69]. It has also been demonstrated that different breeds regulate RuT differently [18] and that thermoregulatory capacity varies among individuals of the same breed, effected by age and physiological state [70]. Lastly, despite some variations in retention rate depending on the bolus size in sheep [71], the devices can be safely retrieved at slaughter ensuring the animal remains safe for human consumption.…”

Section: Rumen/reticular Bolusesmentioning

confidence: 99%

Technologies for the automated collection of heat stress data in sheep

et al. 2021

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The automated collection of phenotypic measurements in livestock is becoming increasingly important to both researchers and farmers. The capacity to non-invasively collect real-time data, provides the opportunity to better understand livestock behaviour and physiology and improve animal management decisions. Current climate models project that temperatures will increase across the world, influencing both local and global agriculture. Sheep that are exposed to high ambient temperatures experience heat stress and their physiology, reproductive function and performance are compromised. Body temperature is a reliable measure of heat stress and hence a good indicator of an animals’ health and well-being. Non-invasive temperature-sensing technologies have made substantial progress over the past decade. Here, we review the different technologies available and assess their suitability for inferring ovine heat stress. Specifically, the use of indwelling probes, intra-ruminal bolus insertion, thermal imaging and implantable devices are investigated. We further evaluate the capacity of behavioural tracking technology, such as global positioning systems, to identify heat stressed individuals based on the exhibition of specific behaviours. Although there are challenges associated with using real-time thermosensing data to make informed management decisions, these technologies provide new opportunities to manage heat stress in sheep. In order to obtain accurate real-time information of individual animals and facilitate prompt intervention, data collection should be entirely automated. Additionally, for accurate interpretation on-farm, the development of software which can effectively collect, manage and integrate data for sheep producer’s needs to be prioritised. Lastly, understanding known physiological thresholds will allow farmers to determine individual heat stress risk and facilitate early intervention to reduce the effects in both current and subsequent generations.

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Thermoregulatory response to outdoor heat stress of hair sheep females at different physiological state

Cited by 13 publications

References 32 publications

Physiological response to thermal stress in hair-sheep ewes during subtropical summer

Physiological response to thermal stress in hair-sheep ewes during subtropical summer

Termorregulación y respuestas reproductivas de carneros bajo estrés por calor. Revisión

Technologies for the automated collection of heat stress data in sheep

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