Journal article

Differences in Thermoregulatory Responses between Dorper and Second Cross Lambs to Heat Stress Challenges

Aleena Joy, Frank R Dunshea, Brain J Leury, Kristy DiGiacomo, Iain J Clarke, Minghao Zhang, Archana Abhijith, Richard Osei-Amponsah, Surinder Singh Chauhan

Proceedings | MDPI AG

Abstract

We compared the thermotolerance of Dorper (D) and second cross (SC) (Poll Dorset x Merino/Border Leicester) lambs by assessing physiological and biochemical responses. After acclimatization, 4–5 month old lambs of each breed were exposed to either thermo-neutral (18 °C–21 °C, 40%–50% RH, n = 12/group) or cyclic heat stress (HS) (28 °C–40 °C; 40%–60% RH, n = 12/group) for 2 weeks in climatic chambers. The HS involved exposure to temperatures of 38 °C–40 °C between 0800 and 17.00 h daily; otherwise the temperature was maintained at 28 °C. Elevated temperature increased rectal temperature (p < 0.01), respiration rate (p < 0.01) and skin temperature (p < 0.01) in both breeds, (data for 12.00 and..

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