Effect of Heat Stress on Body Temperature Indices, Respiratory Rate, and Heart Rate in Indigenous Libyan Sheep
DOI:
https://doi.org/10.61952/jlabw.v2i3.570Keywords:
heat stress, local Libyan sheep, temperature, respiratory rate, heart rate, temperature-humidity indexAbstract
This study aimed to evaluate the effect of heat stress on temperature, respiration, and heart rate indicators in local Libyan sheep during the summer season. The study was conducted in Al-Zawiya, Libya, during July and August 2025, and included twenty-five local sheep distributed across five farms, with five animals from each farm. Data were collected over eighteen measurement days, twice daily: in the morning at 08:00 and at noon at 14:00, resulting in a total of 900 measurement records. The recorded variables included ambient temperature, relative humidity, temperature-humidity index, animal temperature, respiratory rate, and heart rate.
The results showed a clear increase in heat load during the noon period compared with the morning period. Mean ambient temperature increased from 26.38 ± 0.14 °C in the morning to 34.81 ± 0.24 °C at noon, while the temperature-humidity index increased from 75.59 ± 0.13 to 82.30 ± 0.15. This increase was associated with significant changes in animal indicators. Animal temperature increased from 38.88 ± 0.01 °C in the morning to 39.65 ± 0.01 °C at noon, respiratory rate increased from 30.27 ± 0.15 to 60.00 ± 0.38 breaths/min, and heart rate increased from 78.35 ± 0.16 to 98.20 ± 0.29 beats/min. All differences were statistically significant at P < 0.001. The results also showed strong positive relationships between the temperature-humidity index and animal temperature, respiratory rate, and heart rate.
The study concluded that heat stress caused clear changes in the measured indicators of local Libyan sheep. Respiratory rate was the most responsive indicator, followed by heart rate and then animal temperature. These findings highlight the importance of improving housing conditions and providing shade, water, and adequate ventilation during periods of high temperature.
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